The present disclosure relates to a magnetoresistance effect device and a magnetoresistance effect module.
Priority is claimed on Japanese Patent Application No. 2018-016680 filed Feb. 1, 2018 and Japanese Patent Application No. 2019-004354 filed Jan. 15, 2019, the contents of which are incorporated herein by reference.
In recent years, as mobile communication terminals such as cellular phones have become more sophisticated, high-speed wireless communication has advanced. Since the communication speed is proportional to the bandwidth of the frequency to be used, the frequency band required for communication is increasing. Along with this, the number of installed high frequency filters required for mobile communication terminals has also increased.
Spintronics has been being studied as a field that can be applied to new high frequency components in recent years. One of the phenomena that is attracting attention in spintronics is a ferromagnetic resonance phenomenon of a magnetoresistance effect element.
When an alternating current or alternating magnetic field is applied to a ferromagnetic layer included in a magnetoresistance effect element, ferromagnetic resonance can be caused in the magnetization of the ferromagnetic layer. When ferromagnetic resonance occurs, the resistance value of the magnetoresistance effect element oscillates cyclically at the ferromagnetic resonance frequency. The ferromagnetic resonance frequency varies depending on the intensity of the magnetic field applied to the ferromagnetic layer, and its ferromagnetic resonance frequency is generally in a high frequency band of several to several tens of GHz.
For example, Japanese Unexamined Patent Publication No. 2017-063397 describes a magnetoresistance effect device usable as a high frequency device such as a high frequency filter utilizing the ferromagnetic resonance phenomenon.
However, high frequency filters using this magnetoresistance effect device do not have frequency characteristics (steepness) in the vicinity of the cutoff frequency which are sufficient.
It is desirable to provide a magnetoresistance effect device having excellent frequency characteristics in the vicinity of the cutoff frequency.
The inventors have found that by combining circuit units (elements) exhibiting predetermined characteristics, the respective characteristics thereof are superimposed on each other so that the steepness of the magnetoresistance effect device can be improved.
That is, the present disclosure provides the following means.
(1) A magnetoresistance effect device according to the first aspect includes: a first port; a second port; a first circuit unit and a second circuit unit which are connected between the first port and the second port; a shared reference potential terminal which is connected to the first circuit unit and the second circuit unit by sharing or a first reference potential terminal and a second reference potential terminal which are connected to the first circuit unit and the second circuit unit, respectively; and a shared DC applying terminal which is capable of connecting a power source for applying a direct current or a direct current voltage to a first magnetoresistance effect element of the first circuit unit and a second magnetoresistance effect element of the second circuit unit by sharing, or a first DC applying terminal and a second DC applying terminal which are capable of connecting a power source for applying a direct current or a direct current voltage to a first magnetoresistance effect element of the first circuit unit and a second magnetoresistance effect element of the second circuit unit, respectively, wherein the first circuit unit includes the first magnetoresistance effect element including a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched therebetween, and a first conductor connected to a first end face in a stacking direction of the first magnetoresistance effect element, the first conductor is formed such that a first end portion of the first conductor is connected to an input side of a high frequency current and a second end portion of the first conductor is connected to the shared reference potential terminal or the first reference potential terminal so that a high frequency current branches to flow to the first magnetoresistance effect element and the shared reference potential terminal or the first reference potential terminal, the second circuit unit includes the second magnetoresistance effect element including a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched therebetween, and a second conductor connected to a first end face in a stacking direction of the second magnetoresistance effect element, the second conductor is formed such that a first end portion of the second conductor is connected to an input side of a high frequency current and a second end portion of the second conductor is connected to the shared reference potential terminal or the second reference potential terminal so that a high frequency current branches to flow to the second magnetoresistance effect element and the shared reference potential terminal or the second reference potential terminal, when the shared DC applying terminal or the first DC applying terminal and the second DC applying terminal are connected to a power source, a positional relationship between the first end face and a second end face opposite to the first end face of the first magnetoresistance effect element in the stacking direction of the first magnetoresistance effect element with respect to a flowing direction of a direct current flowing inside the first magnetoresistance effect element and a positional relationship between the first end face and a second end face opposite to the first end face of the second magnetoresistance effect element in the stacking direction of the second magnetoresistance effect element with respect to a flowing direction of a direct current flowing inside the second magnetoresistance effect element are opposite to each other, and in a case where, when viewed in the stacking direction of the first magnetoresistance effect element, a direction from the first end portion toward the second end portion of the first conductor in a region where the first conductor overlaps the first magnetoresistance effect element is defined as a first direction, a stacking direction of the first magnetoresistance effect element with the first conductor as a reference is defined as a first stacking direction, and a direction of an cross product between the first direction and the first stacking direction is defined as a first cross product direction, and when viewed in the stacking direction of the second magnetoresistance effect element, a direction from the first end portion toward the second end portion of the second conductor in a region where the second conductor overlaps the second magnetoresistance effect element is defined as a second direction, a stacking direction of the second magnetoresistance effect element with the second conductor as a reference is defined as a second stacking direction, and a direction of an cross product between the second direction and the second stacking direction is defined as a second cross product direction, a relative angle between the first cross product direction and the second cross product direction is 90 degrees or less.
(2) A magnetoresistance effect device according to the second aspect includes: a first port; a second port; a first circuit unit and a second circuit unit which are connected between the first port and the second port; a shared reference potential terminal which is connected to the first circuit unit and the second circuit unit by sharing or a first reference potential terminal and a second reference potential terminal which are connected to the first circuit unit and the second circuit unit, respectively; and a shared DC applying terminal which is capable of connecting a power source for applying a direct current or a direct current voltage to a first magnetoresistance effect element of the first circuit unit and a second magnetoresistance effect element of the second circuit unit by sharing, or a first DC applying terminal and a second DC applying terminal which are capable of connecting a power source for applying a direct current or a direct current voltage to a first magnetoresistance effect element of the first circuit unit and a second magnetoresistance effect element of the second circuit unit, respectively, wherein the first circuit unit includes the first magnetoresistance effect element including a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched therebetween, and a first conductor connected to a first end face in a stacking direction of the first magnetoresistance effect element, the first conductor is formed such that a first end portion of the first conductor is connected to an input side of a high frequency current and a second end portion of the first conductor is connected to the shared reference potential terminal or the first reference potential terminal so that a high frequency current branches to flow to the first magnetoresistance effect element and the shared reference potential terminal or the first reference potential terminal, the second circuit unit includes the second magnetoresistance effect element including a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched therebetween, and a second conductor connected to a first end face in a stacking direction of the second magnetoresistance effect element, the second conductor is formed such that a first end portion of the second conductor is connected to an input side of a high frequency current and a second end portion of the second conductor is connected to the shared reference potential terminal or the second reference potential terminal so that a high frequency current branches to flow to the second magnetoresistance effect element and the shared reference potential terminal or the second reference potential terminal, a positional relationship between the first end face and a second end face opposite to the first end face of the first magnetoresistance effect element in the stacking direction of the first magnetoresistance effect element with respect to a connection point on an input side of a direct current or a direct current voltage of the first magnetoresistance effect element and a positional relationship between the first end face and a second end face opposite to the first end face of the second magnetoresistance effect element in the stacking direction of the second magnetoresistance effect element with respect to a connection point on an input side of a direct current or a direct current voltage of the second magnetoresistance effect element are opposite to each other, and in a case where, when viewed in the stacking direction of the first magnetoresistance effect element, a direction from the first end portion toward the second end portion of the first conductor in a region where the first conductor overlaps the first magnetoresistance effect element is defined as a first direction, a stacking direction of the first magnetoresistance effect element with the first conductor as a reference is defined as a first stacking direction, and a direction of an cross product between the first direction and the first stacking direction is defined as a first cross product direction, and when viewed in the stacking direction of the second magnetoresistance effect element, a direction from the first end portion toward the second end portion of the second conductor in a region where the second conductor overlaps the second magnetoresistance effect element is defined as a second direction, a stacking direction of the second magnetoresistance effect element with the second conductor as a reference is defined as a second stacking direction, and a direction of an cross product between the second direction and the second stacking direction is defined as a second cross product direction, a relative angle between the first cross product direction and the second cross product direction is 90 degrees or less.
(3) A magnetoresistance effect device according to the third aspect includes: a first port; a second port; a first circuit unit and a second circuit unit which are connected between the first port and the second port; a shared reference potential terminal which is connected to the first circuit unit and the second circuit unit by sharing or a first reference potential terminal and a second reference potential terminal which are connected to the first circuit unit and the second circuit unit, respectively; and a shared DC applying terminal which is capable of connecting a power source for applying a direct current or a direct current voltage to a first magnetoresistance effect element of the first circuit unit and a second magnetoresistance effect element of the second circuit unit by sharing, or a first DC applying terminal and a second DC applying terminal which are capable of connecting a power source for applying a direct current or a direct current voltage to a first magnetoresistance effect element of the first circuit unit and a second magnetoresistance effect element of the second circuit unit, respectively, wherein the first circuit unit includes the first magnetoresistance effect element including a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched therebetween, and a first conductor connected to a first end face in a stacking direction of the first magnetoresistance effect element, the first conductor is formed such that a first end portion of the first conductor is connected to an input side of a high frequency current and a second end portion of the first conductor is connected to the shared reference potential terminal or the first reference potential terminal so that a high frequency current branches to flow to the first magnetoresistance effect element and the shared reference potential terminal or the first reference potential terminal, the second circuit unit includes the second magnetoresistance effect element including a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched therebetween, and a second conductor connected to a first end face in a stacking direction of the second magnetoresistance effect element, the second conductor is formed such that a first end portion of the second conductor is connected to an input side of a high frequency current and a second end portion of the second conductor is connected to the shared reference potential terminal or the second reference potential terminal so that a high frequency current branches to flow to the second magnetoresistance effect element and the shared reference potential terminal or the second reference potential terminal, when the shared DC applying terminal or the first DC applying terminal and the second DC applying terminal are connected to a power source, a positional relationship between the first end face and a second end face opposite to the first end face of the first magnetoresistance effect element in the stacking direction of the first magnetoresistance effect element with respect to a flowing direction of a direct current flowing inside the first magnetoresistance effect element and a positional relationship between the first end face and a second end face opposite to the first end face of the second magnetoresistance effect element in the stacking direction of the second magnetoresistance effect element with respect to a flowing direction of a direct current flowing inside the second magnetoresistance effect element are the same, and in a case where, when viewed in the stacking direction of the first magnetoresistance effect element, a direction from the first end portion toward the second end portion of the first conductor in a region where the first conductor overlaps the first magnetoresistance effect element is defined as a first direction, a stacking direction of the first magnetoresistance effect element with the first conductor as a reference is defined as a first stacking direction, and a direction of an cross product between the first direction and the first stacking direction is defined as a first cross product direction, and when viewed in the stacking direction of the second magnetoresistance effect element, a direction from the first end portion toward the second end portion of the second conductor in a region where the second conductor overlaps the second magnetoresistance effect element is defined as a second direction, a stacking direction of the second magnetoresistance effect element with the second conductor as a reference is defined as a second stacking direction, and a direction of an cross product between the second direction and the second stacking direction is defined as a second cross product direction, a relative angle between the first cross product direction and the second cross product direction is larger than 90 degrees.
(4) A magnetoresistance effect device according to the fourth aspect includes: a first port; a second port; a first circuit unit and a second circuit unit which are connected between the first port and the second port; a shared reference potential terminal which is connected to the first circuit unit and the second circuit unit by sharing or a first reference potential terminal and a second reference potential terminal which are connected to the first circuit unit and the second circuit unit, respectively; and a shared DC applying terminal which is capable of connecting a power source for applying a direct current or a direct current voltage to a first magnetoresistance effect element of the first circuit unit and a second magnetoresistance effect element of the second circuit unit by sharing, or a first DC applying terminal and a second DC applying terminal which are capable of connecting a power source for applying a direct current or a direct current voltage to the first magnetoresistance effect element of the first circuit unit and the second magnetoresistance effect element of the second circuit unit, respectively, wherein the first circuit unit includes the first magnetoresistance effect element including a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched therebetween, and a first conductor connected to a first end face in a stacking direction of the first magnetoresistance effect element, the first conductor is formed such that a first end portion of the first conductor is connected to an input side of a high frequency current and a second end portion of the first conductor is connected to the shared reference potential terminal or the first reference potential terminal so that a high frequency current branches to flow to the first magnetoresistance effect element and the shared reference potential terminal or the first reference potential terminal, the second circuit unit includes the second magnetoresistance effect element including a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched therebetween, and a second conductor connected to a first end face in a stacking direction of the second magnetoresistance effect element, the second conductor is formed such that a first end portion of the second conductor is connected to an input side of a high frequency current and a second end portion of the second conductor is connected to the shared reference potential terminal or the second reference potential terminal so that a high frequency current branches to flow to the second magnetoresistance effect element and the shared reference potential terminal or the second reference potential terminal, a positional relationship between the first end face and a second end face opposite to the first end face of the first magnetoresistance effect element in the stacking direction of the first magnetoresistance effect element with respect to a connection point on an input side of a direct current or a direct current voltage of the first magnetoresistance effect element and a positional relationship between the first end face and a second end face opposite to the first end face of the second magnetoresistance effect element in the stacking direction of the second magnetoresistance effect element with respect to a connection point on an input side of a direct current or a direct current voltage of the second magnetoresistance effect element are the same, and in a case where, when viewed in the stacking direction of the first magnetoresistance effect element, a direction from the first end portion toward the second end portion of the first conductor in a region where the first conductor overlaps the first magnetoresistance effect element is defined as a first direction, a stacking direction of the first magnetoresistance effect element with the first conductor as a reference is defined as a first stacking direction, and a direction of an cross product between the first direction and the first stacking direction is defined as a first cross product direction, and when viewed in the stacking direction of the second magnetoresistance effect element, a direction from the first end portion toward the second end portion of the second conductor in a region where the second conductor overlaps the second magnetoresistance effect element is defined as a second direction, a stacking direction of the second magnetoresistance effect element with the second conductor as a reference is defined as a second stacking direction, and a direction of an cross product between the second direction and the second stacking direction is defined as a second cross product direction, a relative angle between the first cross product direction and the second cross product direction is larger than 90 degrees.
Hereinafter, the magnetoresistance effect module will be described in detail with reference to the drawings as appropriate. In the drawings used in the following description, in order to facilitate understanding of the features, the characteristic portions are sometimes enlarged for convenience, and the dimensional ratios and the like between the respective components may be different from actual ones. Materials, sizes, and the like illustrated in the following description are merely examples, and the present disclosure is not limited thereto, and may be appropriately modified and implemented within the range that achieves the effects of the present disclosure.
According to the magnetoresistance effect devices of the embodiments described below, it is possible to obtain excellent frequency characteristics in the vicinity of the cutoff frequency.
<First Port and Second Port>
The first port 1 is an input terminal of the magnetoresistance effect module 100. By connecting an alternating current signal source (not shown) to the first port 1, alternating current signals (high frequency signals) can be applied to the magnetoresistance effect module 100. The high frequency signals applied to the magnetoresistance effect module 100 are, for example, signals having a frequency of 100 MHz or more.
The second port 2 is an output terminal of the magnetoresistance effect module 100.
<First Circuit Unit>
The first circuit unit 10 is connected between the first port 1 and the second port 2. A current branch type element 11 is incorporated in the first circuit unit 10. The current branch type element 11 includes a first magnetoresistance effect element 12 and a first conductor 14. The first conductor 14 is connected to one end (a first end face 12a) in a stacking direction of the first magnetoresistance effect element 12. A first end portion 14a of the first conductor 14 is connected to an input side of a high frequency current of the first circuit unit 10 and a second end portion 14b of the first conductor 14 is connected to the reference potential terminal 3A. The high frequency current IRC flowing through the first conductor 14 branches to flow to the first magnetoresistance effect element 12 and the reference potential terminal 3A.
<First Conductor>
The first conductor 14 is a wiring for allowing passing of the high frequency current IRC and also functions as an electrode provided on the first end face 12a in the stacking direction of the first magnetoresistance effect element 12. The first conductor 14 is made of a material having conductivity. For example, Ta, Cu, Au, AuCu, Ru, Al, or the like can be used for the first conductor 14. A counter electrode 15 may be provided on the other end (a second end face 12b) in the stacking direction of the first magnetoresistance effect element 12. For the counter electrode 15, the same materials as exemplified for the first conductor 14 can be used. The other end (the second end face 12b) in the stacking direction of the first magnetoresistance effect element 12 is connected to an output side of the high frequency current IRC in the first circuit unit 10 via the counter electrode 15.
<Magnetoresistance Effect Element>
The first magnetoresistance effect element 12 has a magnetization fixed layer 12A, a magnetization free layer 12B, and a spacer layer 12C. The spacer layer 12C is positioned between the magnetization fixed layer 12A and the magnetization free layer 12B. It is more difficult for the magnetization of the magnetization fixed layer 12A to move than the magnetization of the magnetization free layer 12B and it is fixed in one direction under a predetermined magnetic field environment. The magnetization direction of the magnetization free layer 12B changes relatively with respect to the magnetization direction of the magnetization fixed layer 12A, thereby functioning as the first magnetoresistance effect element 12. Although
The magnetization fixed layer 12A is made of a ferromagnetic material. Preferably, the magnetization fixed layer 12A is made of high spin polarization materials such as Fe, Co, Ni, an alloy of Ni and Fe, an alloy of Fe and Co, or an alloy of Fe, Co and B. By using these materials, a magnetoresistance change rate of the first magnetoresistance effect element 12 is increased. The magnetization fixed layer 12A may be made of a Heusler alloy. Preferably, a film thickness of the magnetization fixed layer 12A is 1 to 20 nm.
There is no particular limitation on a method of fixing the magnetization of the magnetization fixed layer 12A. For example, in order to fix the magnetization of the magnetization fixed layer 12A, an antiferromagnetic layer may be added to be in contact with the magnetization fixed layer 12A. Also, the magnetization of the magnetization fixed layer 12A may be fixed by utilizing the magnetic anisotropy caused by the crystal structure, the form, and the like. FeO, CoO, NiO, CuFeS2, IrMn, FeMn, PtMn, Cr, Mn or the like can be used for the antiferromagnetic layer.
The magnetization free layer 12B is made of a ferromagnetic material the magnetization direction of which can be changed by an externally applied magnetic field or a spin polarized current.
For a material of the magnetization free layer 12B, CoFe, CoFeB, CoFeSi, CoMnGe, CoMnSi, CoMnAl, FeB, Co, a CoCr based alloy, a Co multilayer film, a CoCrPt based alloy, an FePt based alloy, an SmCo alloy including a rare earth element, a TbFeCo alloy or the like can be used. Also, the magnetization free layer 12B may be made of a Heusler alloy.
Preferably, a thickness of the magnetization free layer 12B is about 0.5 to 20 nm. Also, a high spin polarization material may be inserted between the magnetization free layer 12B and the spacer layer 12C. By inserting a high spin polarization material, a high magnetoresistance change rate can be obtained.
A CoFe alloy or a CoFeB alloy can be exemplified as a high spin polarization material. Preferably, a film thickness of both the CoFe alloy and the CoFeB alloy is set to about 0.2 to 1.0 nm.
The spacer layer 12C is a layer disposed between the magnetization fixed layer 12A and the magnetization free layer 12B. The spacer layer 12C is configured by a layer formed of a conductor, an insulator, or a semiconductor, or a layer including a conductive point formed of a conductor in an insulator. Preferably, the spacer layer 12C is a nonmagnetic layer.
For example, the first magnetoresistance effect element 12 becomes a tunneling magnetoresistance (TMR) effect element when the spacer layer 12C is made of an insulator and becomes a giant magnetoresistance (GMR) effect element when the spacer layer 12C is made of metal.
When an insulating material is used as the spacer layer 12C, an insulating material such as Al2O3, MgO or MgAl2O4 can be used. A high magnetoresistance change rate can be obtained by adjusting a film thickness of the spacer layer 12C so that a coherent tunneling effect develops between the magnetization fixed layer 12A and the magnetization free layer 12B. In order to efficiently utilize the TMR effect, preferably, a film thickness of the spacer layer 12C is about 0.5 to 3.0 nm.
When the spacer layer 12C is made of a conductive material, a conductive material such as Cu, Ag, Au or Ru can be used. In order to efficiently utilize the GMR effect, preferably, the film thickness of the spacer layer 12C may be about 0.5 to 3.0 nm.
When the spacer layer 12C is made of a semiconductor material, a material such as ZnO, In2O3, SnO2, ITO, GaOx, or Ga2Ox can be used. In this case, preferably, the film thickness of the spacer layer 12C is about 1.0 to 4.0 nm.
When a layer including a conductive point formed of a conductor in a nonmagnetic insulator is used as the spacer layer 12C, preferably, it has a structure including a conductive point formed of a conductor such as CoFe, CoFeB, CoFeSi, CoMnGe, CoMnSi, CoMnAl, Fe, Co, Au, Cu, Al or Mg in a nonmagnetic insulator made of Al2O3 or MgO or the like. In this case, preferably, the film thickness of the spacer layer 12C is about 0.5 to 2.0 nm.
A cap layer may be provided on a side of the magnetization free layer 12B opposite to the spacer layer 12C side (between the magnetization free layer 12B and the first conductor 14). Preferably, the magnetization free layer 12B and the cap layer is in contact with each other. Further, a seed layer or a buffer layer may be provided between the first magnetoresistance effect element 12 and the counter electrode 15. As the cap layer, the seed layer, or the buffer layer, a metal film of Ru, Ta, Cu, Cr or the like, an oxide film of MgO or the like, or a stacked film thereof can be exemplified. When these layers are made of oxide films, thicknesses of these layers are thin enough to allow a current to flow. For example, preferably, the thickness is a thickness such that a current (including a tunneling current) flows when a voltage of 3 V is applied in the stacking direction of the first magnetoresistance effect element 12, and preferably, it is 5 nm or less, specifically.
Desirably, a size of the first magnetoresistance effect element 12 formed is such that a long side of the first magnetoresistance effect element 12 in a plan view shape is 500 nm or less. Also, desirably, a short side of the first magnetoresistance effect element 12 in a plan view shape is 50 nm or more. When the first magnetoresistance effect element 12 in a plan view shape is not a rectangle (including a square), a long side of a rectangle that circumscribes a shape of the first magnetoresistance effect element 12 in a plan view with a minimum area is defined as the long side of the first magnetoresistance effect element 12 in a plan view shape, and a short side of a rectangle that circumscribes a shape of the first magnetoresistance effect element 12 in a plan view with a minimum area is defined as the short side of the first magnetoresistance effect element 12 in a plan view shape.
When the long side is as small as 500 nm or less, a volume of the magnetization free layer 12B becomes small so that a highly efficient ferromagnetic resonance phenomenon can be realized. Here, the “a plan view shape” is a shape as viewed in the stacking direction of each layer which constitutes the first magnetoresistance effect element 12.
<Second Circuit Unit>
The second circuit unit 20 is connected between the first port 1 and the second port 2. The second circuit unit 20 shown in
The current branch type element 21 shown in
<Reference Potential Terminal>
The reference potential terminals 3A and 3B are directly or indirectly connected to the first circuit unit 10 and the second circuit unit 20, respectively. The reference potential terminals 3A and 3B are connected to a reference potential and determine the reference potential of the magnetoresistance effect module 100. In
<DC Applying Terminal>
The DC applying terminal 4 is connected to the power supply 90 and applies a direct current or a direct current voltage in the stacking direction of the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22. The first magnetoresistance effect element 12 is connected to the DC applying terminal 4 which is capable of connecting the power supply 90 for applying a direct current or a direct current voltage to the first magnetoresistance effect element 12. The second magnetoresistance effect element 22 is connected to the DC applying terminal 4 which is capable of connecting the power supply 90 for applying a direct current or a direct current voltage to the second magnetoresistance effect element 22. In the specification, the direct current is a current of which direction does not change with time and includes a current of which magnitude varies with time. Also, the direct current voltage is a voltage whose polarity does not change with time and also includes a voltage whose magnitude changes with time. The power supply 90 may be a direct current source or a direct current voltage source. The power supply 90 may be a direct current source capable of generating a constant direct current or a direct current voltage source capable of generating a constant direct current voltage. The power supply 90 may be a direct current source capable of changing the magnitude of the generated direct current value or a direct current voltage source capable of changing the magnitude of the generated direct current voltage value.
Preferably, a current density of a direct current applied to each of the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22 is smaller than an oscillation threshold current density of each of the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22. The oscillation threshold current density of each of the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22 is a threshold value of a current density where, by applying a current having a current density equal to or larger than the threshold value, the magnetization of each of the magnetization free layers 12B and 22B starts precession at a constant frequency and constant amplitude, whereby each of the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22 oscillates (outputs (resistance values) of each of the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22 varies at a constant frequency and a constant amplitude).
As shown in
In addition, when the power supply 90 is a direct current voltage source, the power supply 90 is connected to the DC applying terminal 4 such that a direct current voltage by which the first end face 12a of the first magnetoresistance effect element 12 is at a higher potential than the second end face 12b is applied from the DC applying terminal 4 and a direct current voltage by which the second end face 22a of the second magnetoresistance effect element 22 is at a higher potential than the first end face 22a is applied from the DC applying terminal 4.
Also, the positional relationship between the first end face 12a and the second end face 12b of the first magnetoresistance effect element 12 with respect to a connection point on an input side of a direct current or a direct current voltage of the first magnetoresistance effect element 12 and the positional relationship between the first end face 22a and the second end face 22b of the second magnetoresistance effect element 22 with respect to a connection point on an input side of a direct current or a direct current voltage of the second magnetoresistance effect element 22 are opposite to each other.
The “connection point on an input side of a direct current or a direct current voltage” is a connection point on a side where a direct current is applied to the circuit unit or a connection point on a higher potential side set by a direct current voltage source. In the example shown in
In
<Other Constituents>
Inductors 92 and capacitors 94 are disposed in the magnetoresistance effect module 100. The inductor 92 cuts off high frequency components of a current and passes invariant components of a current. The capacitor 94 passes high frequency components of a current and cuts of invariant components of a current. The inductor 92 is disposed in a portion in which flow of the high frequency current IRC is required to be inhibited, and the capacitor 94 is disposed in a portion in which flow of the direct current IDC is required to be inhibited. In
A chip inductor, an inductor with a pattern line, a resistance element with an inductor component, or the like can be used for the inductor 92. Preferably, the inductance of the inductor 92 is 10 nH or more. Known types of capacitor can be used for the capacitor 94.
Each circuit unit and each terminal are connected by a signal line. Preferably, the form of the signal line is defined as a microstrip line (MSL) type or a coplanar waveguide (CPW) type. When there is a design using a microstrip line (MSL) type or a coplanar waveguide (CPW) type, preferably, a line width and a distance between grounds is designed such that the characteristic impedance of the signal line is equal to the impedance of the circuit system. By designing in this manner, the transmission loss of the signal line can be reduced.
In addition, the relative angle between a first cross product direction in the first circuit unit 10 and a second cross product direction in the second circuit unit 20 in the magnetoresistance effect module 100 is 90 degrees or less. The first cross product direction CP1 and the second cross product direction CP2 are defined as follows. Also, in this specification, the “cross product” is a vector product.
When viewed in the stacking direction of the first magnetoresistance effect element 12, the direction from the first end portion 14a toward the second end portion 14b of the first conductor 14 in the region where the first conductor 14 and the first magnetoresistance effect element 12 overlap is defined as a first direction. In other words, when viewed in the stacking direction of the first magnetoresistance effect element 12, the direction from the input side of the high frequency current to the reference potential terminal side in the region where the first conductor 14 and the first magnetoresistance effect element 12 overlap is defined as the first direction. In the first circuit unit 10 of
Further, the stacking direction of the first magnetoresistance effect element 12 with respect to the first conductor 14 is taken as a first stacking direction. In
The first cross product direction CP1 is the direction of the cross product between the first direction and the first stacking direction. Here, “the cross product between the first direction and the first stacking direction” is expressed by the following equation (1).
[Math. 1]
“The cross product between the first direction and the first stacking direction”=a×b (1)
(a: a unit vector in the first direction, b: a unit vector in the first stacking direction)
The first cross product direction CP1 in the first circuit unit 10 of
The second cross product direction CP2 is defined in the same way as the first cross product direction CP1. When viewed in the stacking direction of the second magnetoresistance effect element 22, the direction from the first end portion 24a toward the second end portion 24b of the second conductor 24 in the region where the second conductor 24 and the second magnetoresistance effect element 22 overlap is defined as a second direction. In other words, when viewed in the stacking direction of the second magnetoresistance effect element 22, the direction from the input side of the high frequency current to the reference potential terminal side in the region where the second conductor 24 and the second magnetoresistance effect element 22 overlap is defined as the second direction. In the second circuit unit 20 of
Further, the stacking direction of the second magnetoresistance effect element 22 with respect to the second conductor 24 is taken as a second stacking direction. In the second circuit unit 20 of
The second cross product direction CP2 is the direction of the cross product between the second direction and the second stacking direction. Here, “the cross product between the second direction and the second stacking direction” is expressed by the following equation (2).
[Math. 2]
“The cross product between the second direction and the second stacking direction”=a′×b′ (2)
(a′: a unit vector in the second direction, b′: a unit vector in the second stacking direction)
The second cross product direction CP2 in the second circuit unit 20 of
The relative angle between the first cross product direction CP1 and the second cross product direction CP2 in the magnetoresistance effect module 100 shown in
In addition, preferably, the magnetoresistance effect module 100 has a frequency setting mechanism 80. The frequency setting mechanism 80 is a magnetic field applying mechanism that applies an external magnetic field serving as a static magnetic field to the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22. The frequency setting mechanism 80 sets ferromagnetic resonance frequencies of the magnetization free layers 12B and 22B of the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22. The frequency of the signal output by the magnetoresistance effect module 100 varies depending on the ferromagnetic resonance frequencies of the magnetization free layers 12B and 22B. That is, the frequency of the output signal can be set by the frequency setting mechanism 80.
The frequency setting mechanism 80 may be provided in each of the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22 or may be provided in common. The frequency setting mechanism 80 is configured by a magnetic field applying mechanism of an electromagnetic type or a strip line type capable of variably controlling an applied magnetic field strength using either voltage or current, for example. Further, it may be configured by a combination of a magnetic field applying mechanism of an electromagnetic type or a strip line type capable of variably controlling an applied magnetic field strength and a permanent magnet for supplying only a constant magnetic field.
<Function of Magnetoresistance Effect Device>
When a high frequency signal is input from the first port 1 to the magnetoresistance effect module 100, a high frequency current IRC corresponding to a high frequency signal flows to the first circuit unit 10. The high frequency current IRC branches to flow to the first magnetoresistance effect element 12 and the reference potential terminal 3A.
The magnetization of the magnetization free layer 12B oscillates mainly due to receiving a high frequency magnetic field generated by the high frequency current IRC flowing through the first conductor 14. Due to the ferromagnetic resonance phenomenon, the magnetization of the magnetization free layer 12B greatly oscillates when the frequency of the high frequency current IRC is in the vicinity of the ferromagnetic resonance frequency of the magnetization free layer 12B. When the oscillation of the magnetization of the magnetization free layer 12B becomes large, a change in the resistance value in the first magnetoresistance effect element 12 increases. This change in the resistance value is output from the first magnetoresistance effect element 12 (the first circuit unit 10) by applying the direct current IDC in the stacking direction of the first magnetoresistance effect element 12. A sum of the output due to the change in the resistance value caused by the ferromagnetic resonance phenomenon and the output due to the high frequency current IRC that branches to flow to the first magnetoresistance effect element 12 is output from the first magnetoresistance effect element 12 (the first circuit unit 10). The output due to the change in the resistance value caused by the ferromagnetic resonance phenomenon increases as the change in the resistance value increases. That is, the output from the first magnetoresistance effect element 12 (the first circuit unit 10) becomes larger with respect to a signal having a frequency in the vicinity of the ferromagnetic resonance frequency of the magnetization free layer 12B, and becomes smaller with respect to a signal having a frequency deviating from the vicinity of the ferromagnetic resonance frequency of the magnetization free layer 12B since the amount of variation in the resistance value of the first magnetoresistance effect element 12 is small.
Then, the high frequency current IRC output from the first circuit unit 10 passes through the capacitor 94 and flows to the second circuit unit 20. In the second circuit unit 20, in the same manner as in the first circuit unit 10, the high frequency current IRC branches to flow to the second magnetoresistance effect element 22 and the reference potential terminal 3B. Also, the magnetization of the magnetization free layer 22B oscillates greatly when the frequency of the high frequency current IRC is in the vicinity of the ferromagnetic resonance frequency of the magnetization free layer 22B.
When the oscillation of the magnetization of the magnetization free layer 22B becomes large, a change in the resistance value in the second magnetoresistance effect element 22 increases. This change in the resistance value is output from the second magnetoresistance effect element 22 (the second circuit unit 20) by applying the direct current IDC in the stacking direction of the second magnetoresistance effect element 22. A sum of the output due to the change in the resistance value caused by the ferromagnetic resonance phenomenon and the output due to the high frequency current IRC that branches to flow to the second magnetoresistance effect element 22 is output from the second magnetoresistance effect element 22 (the second circuit unit 20) to be output from the second port 2. The output from the second magnetoresistance effect element 22 (the second circuit unit 20) becomes larger with respect to a signal having a frequency in the vicinity of the ferromagnetic resonance frequency of the magnetization free layer 22B, and becomes smaller with respect to a signal having a frequency deviating from the vicinity of the ferromagnetic resonance frequency of the magnetization free layer 22B since the amount of variation in the resistance value of the second magnetoresistance effect element 22 is small.
The position of the signal peak of the first circuit unit 10 (the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12) and the position of the signal peak of the second circuit unit 20 (the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22) are different from each other, and the frequency at the position of the signal peak of the first circuit unit 10 (the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12) is higher than the frequency at the position of the signal peak of the second circuit unit 20 (the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22). Preferably, the difference between the frequencies of the two signal peaks is within a range of 10% or less and more preferably, it is 5% or less with respect to a center frequency of the two signal peaks (the average value of the frequencies of the two signal peaks). Also, regarding a specific numerical value, the difference between the frequencies of the two signal peaks is preferably 200 MHz or less and more preferably, it is 100 MHz or less. Also, preferably, the difference between the frequencies of the two signal peaks is in the range of 0.5% or more with respect to the center frequency and more preferably, is 5 MHz or more. Although the signal peak in the anti-Lorentzian-like signal characteristic has the upwardly convex peak and the downwardly convex peak, the difference between the frequencies of the two signal peaks described above have been taken as the difference between the frequencies of two downwardly convex peaks. The positions of the signal peaks of the first circuit unit 10 and the second circuit unit 20 can be controlled by the frequency setting mechanism 80. Further, the position of the signal peak of the circuit unit (the ferromagnetic resonance frequency of the magnetization free layer of the magnetoresistance effect element) can also be changed depending on a plan view shape of the magnetoresistance effect element and a configuration of layers of the magnetoresistance effect element.
When the signal characteristics of the first circuit unit 10 and the signal characteristics of the second circuit unit 20 are superimposed on each other, the signal characteristic of the magnetoresistance effect module 100 is obtained. As shown in
Although the embodiments of the present disclosure have been described above in detail with reference to the drawings, it should be understood that each configuration in each embodiment and combinations thereof are merely examples, and additions, omissions, substitutions and other changes of the configurations are possible without departing from the spirit of the present disclosure.
In addition, in the magnetoresistance effect module 101 shown in
Further, in
The positional relationship between the first end face 12a and the second end face 12b of the first magnetoresistance effect element 12 with respect to the connection point on the input side of the direct current or the direct current voltage of the first magnetoresistance effect element 12 and the positional relationship between the first end face 22a and the second end face 22b of the second magnetoresistance effect element 22 with respect to the connection point on the input side of the direct current or the direct current voltage of the second magnetoresistance effect element 22 are opposite to each other.
Also,
The high frequency current IRC input from the first port 1 branches to flow to the first magnetoresistance effect element 12 and the reference potential terminal 3A. When viewed in the stacking direction of the first magnetoresistance effect element 12, the first direction in the first circuit unit 10 of
In addition, the first magnetoresistance effect element 12 is positioned above the first conductor 14 with the first conductor 14 as a reference. The first stacking direction in the first circuit unit 10 of
The first cross product direction CP1 is the direction of the cross product between the first direction and the first stacking direction. That is, the first cross product direction CP1 in the first circuit unit 10 of
Also, the high frequency current IRC output from the first circuit unit 10 branches to flow to the second magnetoresistance effect element 22 and the reference potential terminal 3B. When viewed in the stacking direction of the second magnetoresistance effect element 22, the second direction in the second circuit unit 20 of
In addition, the second magnetoresistance effect element 22 is positioned below the first conductor 24 with the first conductor 24 as a reference. The second stacking direction in the second circuit unit 20 of
The second cross product direction CP2 is the direction of the cross product between the second direction and the second stacking direction. That is, the second cross product direction CP2 in the second circuit unit 10 of
Further, the direct current IDC in the first magnetoresistance effect element 12 flows from the first end face 12a side toward the second end face 12b and the direct current IDc in the second magnetoresistance effect element 22 flows from the second end face 22b side toward the first end face 22a side. Therefore, also in the magnetoresistance effect module 102 shown in
Also,
As shown in
Also,
In this case, the first cross product direction CP1 is inclined from the first cross product direction CP1 shown in the case of
As described above, the cases where the magnetoresistance effect module shows signal characteristics of a bandpass type have been exemplified. On the other hand, by reversing the direction of the direct current applied between the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22, the trends of the signal characteristics of the first circuit unit 10 and the second circuit unit 20 are reversed, and therefore, the magnetoresistance effect module can also exhibit signal characteristics of a band stop type.
In the case of the band stop type, it is preferable that the difference between the frequency at the position of the signal peak of the first circuit unit 10 (the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12) and the frequency at the position of the signal peak of the second circuit unit 20 (the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22) is in the same range as in the bandpass type. The difference between the frequencies of the two signal peaks in the case of the band stop type means the difference between the frequencies of the two downwardly convex peaks.
A high frequency current IRC input from the first port 1 branches to flow to a first magnetoresistance effect element 12 and the reference potential terminal 3A. When viewed in a stacking direction of the first magnetoresistance effect element 12, a first direction in the first circuit unit 10 of
In addition, the first magnetoresistance effect element 12 is positioned below the first conductor 14 with the first conductor 14 as a reference. A first stacking direction in the first circuit unit 10 of
A first cross product direction CP1 is the direction of the cross product between the first direction and the first stacking direction. That is, the first cross product direction CP1 in the first circuit unit 10 of
The high frequency current IRC output from the first circuit unit 10 branches to flow to a second magnetoresistance effect element 22 and the reference potential terminal 3C. When viewed in the stacking direction of the second magnetoresistance effect element 22, a second direction in the second circuit unit 20 of
Also, the second magnetoresistance effect element 22 is positioned below the first conductor 24 with the first conductor 24 as a reference. A second stacking direction in the second circuit unit 20 of
A second cross product direction CP2 is the direction of the cross product between the second direction and the second stacking direction. That is, the second cross product direction CP2 of the second circuit unit 10 of
On the other hand, a direct current IDC in the first magnetoresistance effect element 12 flows from a first end face 12a side toward a second end face 12b. Also, a direct current IDC in the second magnetoresistance effect element 22 flows from a first end face 22a side toward a second end face 22b. That is, when the DC applying terminal 4 is connected to the power supply 90, the positional relationship between the first end face 12a and the second end face 12b of the first magnetoresistance effect element 12 with respect to the flowing direction of the direct current IDC flowing inside the first magnetoresistance effect element 12 and the positional relationship between the first end face 22a and the second end face 22b of the second magnetoresistance effect element 22 with respect to the flowing direction of the direct current IDC flowing inside the second magnetoresistance effect element 22 are the same.
Also, the positional relationship between the first end face 12a and the second end face 12b in the first magnetoresistance effect element 12 with respect to a connection point on an input side of a direct current or a direct current voltage of the first magnetoresistance effect element 12 and the positional relationship between the first end face 22a and the second end face 22b in the second magnetoresistance effect element 22 with respect to a connection point on an input side of a direct current or a direct current voltage of the second magnetoresistance effect element 22 are the same.
In the magnetoresistance effect module 105 according to the second embodiment, since the relationship between the first cross product direction CP1 and the second cross product direction CP2 and the relationships between the first end faces 12a and 22a and the second end faces 12b and 22b in the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22 with respect to the direct current IDC satisfies the above relationships, the signal characteristics of the current branch type element 11 and the current branch type element 21 are superimposed on each other so that the signal characteristic having excellent steepness can be obtained. The signal characteristics of the magnetoresistance effect module 105 according to the second embodiment are the same as those in
Also,
The relative angle between the first cross product direction CP1 and the second cross product direction CP2 is 180 degrees and is larger than 90 degrees. Further, when the DC applying terminal 4 is connected to the power supply 90, the positional relationship between the first end face 12a and the second end face 12b in the first magnetoresistance effect element 12 with respect to the flowing direction of the direct current IDC flowing inside the first magnetoresistance effect element 12 and the positional relationship between the first end face 22a and the second end face 22b in the second magnetoresistance effect element 22 with respect to the flowing direction of the direct current IDC flowing inside the second magnetoresistance effect element 22 are the same. Also, the positional relationship between the first end face 12a and the second end face 12b in the first magnetoresistance effect element 12 with respect to the connection point on the input side of the direct current or the direct current voltage of the first magnetoresistance effect element 12 and the positional relationship between the first end face 22a and the second end face 22b in the second magnetoresistance effect element 22 with respect to the connection point on the input side of the direct current or the direct current voltage of the second magnetoresistance effect element 22 are the same. Therefore, the signal characteristics of the first circuit unit 10 and the second circuit unit 20 are superimposed on each other so that the signal characteristic having excellent steepness as shown in
Also,
In this case, the first cross product direction CP1 is inclined from the first cross product direction CP1 shown in the case of
Further, although the second embodiment has been described on the basis of the example in which the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22 share the current applying terminal 4 and the power supply 90, each of the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22 may have a current applying terminal 4 and a power supply 90.
The third circuit unit 30 shown in
In
The third magnetoresistance effect element 32 has a magnetization fixed layer 32A, a magnetization free layer 32B, and a spacer layer 32C. A first electrode 37 is provided at one end (a first end face 32a) in a stacking direction of the third magnetoresistance effect element 32 and a counter electrode 38 is provided at the other end (a second end face 32b) in the stacking direction thereof. The third magnetoresistance effect element 32 is connected to a DC applying terminal 4 which is capable of connecting a power supply 90 for applying a direct current or a direct current voltage to the third magnetoresistance effect element 32.
The third conductor 34 is disposed separately from the third magnetoresistance effect element 32 with an insulator 36 interposed therebetween. The insulator 36 is thick enough to maintain the insulation between the third conductor 34 and the first electrode 37. For example, preferably, the thickness is such that a current (including a tunneling current) does not flow therethrough when a voltage of 4.5 V is applied in the stacking direction of the third magnetoresistance effect element 32, and specifically, it is preferably 10 nm or more. A first end portion 34a of the third conductor 34 is connected to an input side of a high frequency current IRC in the third circuit unit 30. In the example of
The magnetization of the magnetization free layer 32B oscillates upon receiving a high frequency magnetic field generated by the high frequency current IRC flowing through the third conductor 34. The magnetization of the magnetization free layer 32B oscillates greatly when the frequency of the high frequency current IRC is in the vicinity of the ferromagnetic resonance frequency of the magnetization free layer 32B. As the oscillation of the magnetization of the magnetization free layer 32B increases, a change in the resistance value in the third magnetoresistance effect element 32 increases. This change in the resistance value is output from the third magnetoresistance effect element 32 (the third circuit unit 30) by applying a direct current IDC in the stacking direction of the third magnetoresistance effect element 32.
As described above, the first circuit unit 10 and the second circuit unit 20 individually exhibit the anti-Lorentzian-like signal characteristic. On the other hand, the third circuit unit 30 incorporating the magnetic field driven type element 31 individually exhibits a Lorentzian-like signal characteristic. Lorentzian signal characteristics are signal characteristics that can be fitted to a Cauchy-Lorentz distribution, and Lorentzian-like signal characteristics are signal characteristics having either one of a peak in which a pass characteristic is increased or a peak in which a pass characteristic is decreased. It is considered that the difference between the signal characteristic of the third circuit unit 30 and the signal characteristic of the first circuit unit 10 and the second circuit unit 20 is caused by a difference in a configuration of an element, a difference in a flowing direction of the high frequency current with respect to the magnetoresistance effect element, and the like.
When the signal characteristic of the first circuit unit 10, the signal characteristic of the second circuit unit 20, and the signal characteristic of the third circuit unit 30 incorporating the magnetic field driven type element 31 are superimposed on each other, the signal characteristic of the magnetoresistance effect module 108 can be obtained. By superimposing the Lorentzian-like signal characteristic of the magnetic field driven type element 31, the bandwidth of the magnetoresistance effect module 108 can be widened. Preferably, the frequency at the position of the signal peak of the third circuit unit 30 is a frequency between the frequency at the position of the signal peak of the first circuit unit 10 and the frequency at the position of the signal peak of the second circuit unit 20. That is, preferably, the ferromagnetic resonance frequency of the magnetization free layer 32B of the third magnetoresistance effect element 32 in the magnetic field driven type element 31 is a frequency between the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12 and the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22.
Further, by adding the Lorentzian-like signal characteristic of the magnetic field driven type element 31, it is possible to increase the difference between the frequency at the position of the signal peak of the first circuit unit 10 (the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12) and the frequency at the position of the signal peak of the second circuit unit 20 (the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22). Preferably, the difference between the frequencies of the two signal peaks is in the range of 30% or less with respect to a center frequency of the two signal peaks and more preferably, is in the range of 15% or less. Also, regarding a specific numerical value as an example, preferably, the difference between the frequencies of the two signal peaks is 400 MHz or less and more preferably, is 200 MHz or less. Also, preferably, the difference between the frequencies of the two signal peaks is in the range of 0.5% or more with respect to the center frequency and more preferably, is 5 MHz or more. Although the signal peak in the anti-Lorentzian-like signal characteristic has a upwardly convex peak and a downwardly convex peak, the difference between the frequencies of the two signal peaks described above is taken as the difference between the frequencies of the two downwardly convex peaks. The positions of the signal peaks of the first circuit unit 10, the second circuit unit 20 and the third circuit unit 30 incorporating the magnetic field driven type element 31 can be controlled by a frequency setting mechanism 80. Also, the position of the signal peak of the circuit unit (the ferromagnetic resonance frequency of the magnetization free layer of the magnetoresistance effect element) can also be changed depending on a plan view shape of the magnetoresistance effect element and a configuration of layers of the magnetoresistance effect element.
In the magnetic field driven type element 31 shown in
In the magnetoresistance effect module 108 shown in
In addition, as in the magnetoresistance effect module 109 shown in
In
Also, in
In addition,
Also, in each connection state of the circuit units shown in
Also,
Specifically, the relative angle between the first cross product direction CP1 of the first circuit unit 10 and the second cross product direction CP2 of the second circuit unit 20 is 180 degrees and is larger than 90 degrees.
Further, the direct current IDC in the first magnetoresistance effect element 12 flows from the second end face 12b side toward the first end face 12a. Also, the direct current IDc in the second magnetoresistance effect element 22 flows from the second end face 22b side toward the first end face 22a. That is, when the DC applying terminal 4 is connected to the power supply 90, the positional relationship between the first end face 12a and the second end face 12b in the first magnetoresistance effect element 12 with respect to the flowing direction of the direct current IDC flowing inside the first magnetoresistance effect element 12 and the positional relationship between the first end face 22a and the second end face 22b in the second magnetoresistance effect element 22 with respect to the flowing direction of the direct current IDC flowing inside the second magnetoresistance effect element 22 are the same.
As described above, according to the magnetoresistance effect modules 108, 109, 109A to 109D and 110 according to the present embodiment, as shown in
The third circuit unit 30 shown in
The fourth magnetoresistance effect element 42 has a magnetization fixed layer 42A, a magnetization free layer 42B and a spacer layer 42C. When a cap layer is provided on a side of the magnetization free layer 42B opposite to the spacer layer 42C side (between the magnetization free layer 42B and the first electrode 44), preferably, the cap layer is a metal film. Preferably, the magnetization free layer 42B and the cap layer are in contact with each other. The first electrode 44 is provided at one end in a stacking direction of the fourth magnetoresistance effect element 42 and a counter electrode 45 is provided at the other end in the stacking direction. One end (a first end face 42a) of the fourth magnetoresistance effect element 42 in the stacking direction is connected to an input side of a high frequency current IRC in the third circuit unit 30, the other end (a second end face 42b) of the fourth magnetoresistance effect element 42 in the stacking direction is connected to an output side of the high frequency current IRC in the third circuit unit 30, and the high frequency current IRC flows through the fourth magnetoresistance effect element 42 without branching to the reference potential terminal 3 side. The first port 1, the fourth magnetoresistance effect element 42 and the second port 2 are connected in series in this order. In the example of
The magnetization of the magnetization free layer 42B oscillates when receiving a spin transfer torque accompanying the high frequency current IRC flowing through the fourth magnetoresistance effect element 42. The magnetization of the magnetization free layer 42B oscillates greatly when the frequency of the high frequency current IRC is in the vicinity of the ferromagnetic resonance frequency of the magnetization free layer 42B. When the oscillation of the magnetization of the magnetization free layer 42B increases, a change in the resistance value in the fourth magnetoresistance effect element 42 increases. This change in the resistance value is output from the fourth magnetoresistance effect element 42 (the third circuit unit 30) by applying the direct current IDC in the stacking direction of the fourth magnetoresistance effect element 42. A sum of the output due to the change in the resistance value resulting from this ferromagnetic resonance phenomenon and the output due to the high frequency current IRC flowing through the fourth magnetoresistance effect element is output from the fourth magnetoresistance effect element 42 (the third circuit unit 30).
The signal characteristic of the third circuit unit 30 incorporating the current driven type element 41 is the Lorentzian-like signal characteristic when individually adopted. It is considered that the difference in the signal characteristic of the third circuit unit 30 with respect to the first circuit unit 10 and the second circuit unit 20 results from a configuration of an element, a way of flowing the high frequency current with respect the magnetoresistance effect element, a difference of the driving force for oscillating the magnetization of the magnetization free layer 42B, and the like. For that reason, as in
By superimposing t the Lorentzian-like signal characteristic of the third circuit unit 30 incorporating the current driven type element 41, the bandwidth of the magnetoresistance effect module 111 is widened. Preferably, the frequency at the position of the signal peak of the third circuit unit 30 is a frequency between the frequency at the position of the signal peak of the first circuit unit 10 and the frequency at the position of the signal peak of the second circuit unit 20. That is, preferably, the ferromagnetic resonance frequency of the magnetization free layer 42B of the fourth magnetoresistance effect element 42 in the current driven type element 41 is a frequency between the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12 and the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22.
In addition, by adding the Lorentzian-like signal characteristic of the third circuit unit 30 incorporating the current driven type element 41, the difference between the frequency at the position of the signal peak of the first circuit unit 10 (the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12) and the frequency at the position of the signal peak of the second circuit unit 20 (the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22) can be increased. Preferably, the difference between the frequencies of the two signal peaks is in the range of 30% or less with respect to a center frequency of the two signal peaks and more preferably, is in the range of 15% or less. Also, regarding a specific numerical value, preferably, the difference between the frequencies of the two signal peaks is 400 MHz or less and more preferably, is 200 MHz or less. Also, preferably, the difference between the frequencies of the two signal peaks is in the range of 0.5% or more with respect to the center frequency and more preferably, is 5 MHz or more. Although the signal peak in the anti-Lorentzian-like signal characteristic has an upwardly convex peak and a downwardly convex peak, the difference between the frequencies of the two signal peaks described above is taken as a difference between the frequencies of the two downwardly convex peaks. The positions of the signal peaks of the first circuit unit 10, the second circuit unit 20 and the third circuit unit 30 incorporating the current driven type element 41 can be controlled by a frequency setting mechanism 80. Further, the position of the signal peak of the circuit unit (the ferromagnetic resonance frequency of the magnetization free layer of the magnetoresistance effect element) can also be changed depending on a plan view shape of the magnetoresistance effect element and a configuration of layers of the magnetoresistance effect element.
Also, in the fourth embodiment, the third circuit unit 30 may be connected in series or in parallel with at least one of the first circuit unit 10 and the second circuit unit 20. For that reason, all of the connection types shown in
Further, desirably, the size of the fourth magnetoresistance effect element 42 formed is such that a long side of the fourth magnetoresistance effect element 42 in a plan view shape is set to 250 nm or less. In addition, desirably, a short side of the fourth magnetoresistance effect element 42 in a plan view shape is 20 nm or more. In the case of the current driven type element 41, preferably, the size of the fourth magnetoresistance effect element 42 is small. When the size of the fourth magnetoresistance effect element 42 becomes smaller, the effect of the spin transfer torque becomes greater, so that a highly efficient ferromagnetic resonance phenomenon can be obtained.
Preferably, the area of the fourth magnetoresistance effect element 42 in a plan view shape is smaller than the area of the first magnetoresistance effect element 12 in a plan view shape and the area of the second magnetoresistance effect element 22 in a plan view shape.
Also, similarly to the first circuit unit 10 and the second circuit unit 20, when the flowing direction of the direct current IDC flowing into the fourth magnetoresistance effect element 42 is reversed, the tendency of the signal characteristic of the third circuit unit 30 incorporating the current driven type element 41 is reversed.
As shown in
In the case of the band stop type, it is preferable that the difference between the frequency at the position of the signal peak of the first circuit unit 10 (the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12) and the frequency at the position of the signal peak of the second circuit unit 20 (the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22) is in the same range as in of the bandpass type. The difference between the frequencies of the two signal peaks in the case of the band stop type means a difference between the frequencies of the two downwardly convex peaks.
Also, as in the magnetoresistance effect module 111A shown in
Also,
Specifically, the relative angle between the first cross product direction CP1 of the first circuit unit 10 and the second cross product direction CP2 of the second circuit unit 20 is 180 degrees and is larger than 90 degrees.
Also, in the first magnetoresistance effect element 12, the direct current IDC flows from the second end face 12b side toward the first end face 12a. Also, in the second magnetoresistance effect element 22, the direct current IDCflows from the second end face 22b side toward the first end face 22a. That is, when the DC applying terminal 4 is connected to the power supply 90, the positional relationship between the first end face 12a and the second end face 12b in the first magnetoresistance effect element 12 with respect to the flowing direction of the direct current IDC flowing inside the first magnetoresistance effect element 12 and the positional relationship between the first end face 22a and the second end face 22b in the second magnetoresistance effect element 22 with respect to the flowing direction of the direct current IDC flowing inside the second magnetoresistance effect element 22 are the same.
As described above, according to the magnetoresistance effect modules 111, 111A and 112 according to the present embodiment, excellent steepness of the magnetoresistance effect modules 111, 111A and 112 can be obtained as shown in
The third circuit unit 30 shown in
The fifth magnetoresistance effect element 52 has a magnetization fixed layer 52A, a magnetization free layer 52B and a spacer layer 52C. When a cap layer is provided on a side of the magnetization free layer 52B opposite to the spacer layer 52C side (between the magnetization free layer 52B and a first electrode 54), preferably, the cap layer is a metal film. Preferably, the magnetization free layer 52B and the cap layer are in contact with each other. The first electrode 54 is provided at one end of the fifth magnetoresistance effect element 52 in the stacking direction and a counter electrode 55 is provided at the other end thereof in the stacking direction. One end (a first end face 52a) of the fifth magnetoresistance effect element 52 is connected to an input side and an output side (a second port 2) of a high frequency current IRC in the third circuit unit 30, and the other end (a second end face 52b) of the fifth magnetoresistance effect element 52 is connected to the reference potential terminal 3. When viewed from the input side of the high frequency current IRC in the third circuit unit 30, the output side (the second port 2) of the high frequency current IRC and the reference potential terminal 3 are in a parallel positional relationship. That is, for the high frequency current IRC, the second port 2 and the reference potential terminal 3 are in a parallel positional relationship. In other words, the fifth magnetoresistance effect element 52 is connected in parallel to the first port 1 and the second port 2. The high frequency current IRC branches to flow to the output side of the high frequency current IRC in the third circuit unit 30 and the fifth magnetoresistance effect element 52. In the example of
The magnetization of the magnetization free layer 52B oscillates when receiving a spin transfer torque accompanying the high frequency current IRC flowing in the fifth magnetoresistance effect element 52. The magnetization of the magnetization free layer 52B oscillates greatly when the frequency of the high frequency current IRC is in the vicinity of the ferromagnetic resonance frequency of the magnetization free layer 52B. When the oscillation of the magnetization of the magnetization free layer 52B increases, a change in the resistance value in the fifth magnetoresistance effect element 52 increases. This change in the resistance value is output from the fifth magnetoresistance effect element 52 by applying the direct current IDC in the stacking direction of the fifth magnetoresistance effect element 52. A sum of the output due to the change in the resistance value resulting from this ferromagnetic resonance phenomenon and the output due to the high frequency current IRC flowing on the output side of the high frequency current IRC in the third circuit unit 30 is output from the third circuit unit 30.
The signal characteristic of the third circuit unit 30 incorporating the current driven type element 51 is the Lorentzian-like signal characteristic when individually adopted. It is considered that the difference in the signal characteristic of the third circuit unit 30 with respect to the first circuit unit 10 and the second circuit unit 20 results from a configuration of an element, a way of flowing the high frequency current with respect the magnetoresistance effect element, a difference of the driving force for oscillating the magnetization of the magnetization free layer 52B, and the like. For that reason, as in
By superimposing the Lorentzian-like signal characteristic of the third circuit unit 30 incorporating the current driven type element 51, the bandwidth of the magnetoresistance effect module 113 is widened. Preferably, the frequency at the position of the signal peak of the third circuit unit 30 is a frequency between the frequency at the position of the signal peak of the first circuit unit 10 and the frequency at the position of the signal peak of the second circuit unit 20. That is, preferably, the ferromagnetic resonance frequency of the magnetization free layer 52B of the fifth magnetoresistance effect element 52 in the current driven type element 51 is a frequency between the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12 and the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22.
In addition, by adding the Lorentzian-like signal characteristic of the third circuit unit 30 incorporating the current driven type element 51, the difference between the frequency at the position of the signal peak of the first circuit unit 10 (the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12) and the frequency at the position of the signal peak of the second circuit unit 20 (the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22) can be increased. Preferably, the difference between the frequencies of the two signal peaks is in the range of 30% or less with respect to a center frequency of the two signal peaks and more preferably, is in the range of 15% or less. Also, regarding a specific numerical value, preferably, the difference between the frequencies of the two signal peaks is 400 MHz or less and more preferably, is 200 MHz or less. Also, preferably, the difference between the frequencies of the two signal peaks is in the range of 0.5% or more with respect to the center frequency and more preferably, is 5 MHz or more. Although the signal peak in the anti-Lorentzian-like signal characteristic has an upwardly convex peak and a downwardly convex peak, the difference between the frequencies of the two signal peaks described above is taken as a difference between the frequencies of the two downwardly convex peaks. The positions of the signal peaks of the first circuit unit 10, the second circuit unit 20 and the third circuit unit 30 incorporating the current driven type element 51 can be controlled by a frequency setting mechanism 80. Further, the position of the signal peak of the circuit unit (the ferromagnetic resonance frequency of the magnetization free layer of the magnetoresistance effect element) can also be changed depending on a plan view shape of the magnetoresistance effect element and a configuration of layers of the magnetoresistance effect element.
Also, in the fourth embodiment, the third circuit unit 30 may be connected in series or in parallel with at least one of the first circuit unit 10 and the second circuit unit 20. For that reason, all of the connection types shown in
Further, desirably, the size of the fifth magnetoresistance effect element 52 formed is such that a long side of the fifth magnetoresistance effect element 52 in a plan view shape is set to 250 nm or less. In addition, desirably, a short side of the fifth magnetoresistance effect element 52 in a plan view shape is 20 nm or more. In the case of the current driven type element 51, preferably, the size of the fifth magnetoresistance effect element 52 is small. When the size of the fifth magnetoresistance effect element 52 becomes smaller, the effect of the spin transfer torque becomes greater, so that a highly efficient ferromagnetic resonance phenomenon can be obtained. Preferably, the area of the fifth magnetoresistance effect element 52 in a plan view shape is smaller than the area of the first magnetoresistance effect element 12 in a plan view shape and the area of the second magnetoresistance effect element 22 in a plan view shape.
Also, similarly to the first circuit unit 10 and the second circuit unit 20, when the flowing direction of the direct current IDC flowing in the fifth magnetoresistance effect element 52 is reversed, the tendency of the signal characteristic of the third circuit unit 30 incorporating the current driven type element 51 is reversed. That is, the signal characteristic of the magnetoresistance effect module 107 is the same as the signal characteristic shown in
In the case of the band stop type, it is preferable that the difference between the frequency at the position of the signal peak of the first circuit unit 10 (the ferromagnetic resonance frequency of the magnetization free layer 12B of the first magnetoresistance effect element 12) and the frequency at the position of the signal peak of the second circuit unit 20 (the ferromagnetic resonance frequency of the magnetization free layer 22B of the second magnetoresistance effect element 22) is in the same range as in the bandpass type. The difference between the frequencies of the two signal peaks in the case of the band stop type means a difference between the frequencies of the two downwardly convex peaks.
Also, as in the magnetoresistance effect module 113A shown in
Also,
Specifically, the relative angle between the first cross product direction CP1 of the first circuit unit 10 and the second cross product direction CP2 of the second circuit unit 20 is 180 degrees and is larger than 90 degrees.
Also, in the first magnetoresistance effect element 12, the direct current IDC flows from the second end face 12b side toward the first end face 12a. Also, in the second magnetoresistance effect element 22, the direct current IDC flows from the second end face 22b side toward the first end face 22a. That is, when the DC applying terminal 4 is connected to the power supply 90, the positional relationship between the first end face 12a and the second end face 12b in the first magnetoresistance effect element 12 with respect to the flowing direction of the direct current IDC flowing inside the first magnetoresistance effect element 12 and the positional relationship between the first end face 22a and the second end face 22b in the second magnetoresistance effect element 22 with respect to the flowing direction of the direct current IDC flowing inside the second magnetoresistance effect element 22 are the same.
As described above, according to the magnetoresistance effect modules 113, 113A and 114 according to the present embodiment, excellent steepness of the magnetoresistance effect modules 113, 113A and 114 can be obtained as shown in
Also,
The inductor 92 in the above embodiment can be changed to a resistance element. This resistance element has a function of cutting a high frequency component of a current by a resistance component. This resistance element may be any of a chip resistor and a resistor based on a pattern line. Preferably, a resistance value of the resistance element is equal to or higher than the characteristic impedance of the signal line output from the magnetoresistance effect element. For example, when the characteristic impedance of the signal line is 50Ω and the resistance value of the resistance element is 50Ω, high frequency power of 45% can be cut by the resistance element. In addition, when the characteristic impedance of the signal line is 50Ω and the resistance value of the resistance element is 500Ω, high frequency power of 90% can be cut by the resistance element. Even in this case, the output signal output from the magnetoresistance effect element can flow efficiently to the second port 2.
In the above embodiment, the inductor 92 may be omitted if the power supply 90 connected to the DC applying terminal 4 has a function of passing an invariant component of a current at the same time as cutting the high frequency component of the current off. Also in this case, the output signal output from the magnetoresistance effect element can flow efficiently to the second port 2.
Also, in the above embodiment, the frequency setting mechanism 80 has been described as a magnetic field applying mechanism. However, other examples described below can be used for the frequency setting mechanism 80. For example, an electric field applying mechanism that applies an electric field to the magnetoresistance effect element may be used as a frequency setting mechanism. When the electric field applied to the magnetization free layer of the magnetoresistance effect element is changed by the electric field applying mechanism, an anisotropic magnetic field in the magnetization free layer is changed and an effective magnetic field in the magnetization free layer is changed. Then, the ferromagnetic resonance frequency of the magnetization free layer is set.
Also, for example, a piezoelectric body and an electric field applying mechanism may be combined as a frequency setting mechanism. The piezoelectric body is provided in the vicinity of the magnetization free layer of the magnetoresistance effect element and an electric field is applied to the piezoelectric body. The piezoelectric body to which the electric field is applied is deformed to distort the magnetization free layer. When the magnetization free layer is distorted, the anisotropic magnetic field in the magnetization free layer is changed and the effective magnetic field in the magnetization free layer is changed. Then, the ferromagnetic resonance frequency of the magnetization free layer is set.
Also, for example, a control film which is an antiferromagnetic material or a ferrimagnetic material having an electromagnetic effect, a mechanism which applies a magnetic field to the control film, and a mechanism which applies an electric field to the control film may be used for the frequency setting mechanism. An electric field and a magnetic field are applied to the control film provided to magnetically couple with the magnetization free layer. When at least one of the electric field and the magnetic field applied to the control film is changed, the exchange coupling magnetic field in the magnetization free layer is changed and the effective magnetic field in the magnetization free layer is changed. Then, the ferromagnetic resonance frequency of the magnetization free layer is set.
Also, in the case where the ferromagnetic resonance frequency of the magnetization free layer of the magnetoresistance effect element is a desired frequency even if the frequency setting mechanism 80 is not provided (even if a static magnetic field is not applied from the magnetic field applying mechanism), the frequency setting mechanism 80 may not be provided.
When a magnetic field applying mechanism is used as the frequency setting mechanism 80, it is preferable to provide only one magnetic field applying mechanism for the magnetoresistance effect elements by sharing since the manufacturing cost is reduced. Further, an external magnetic field in the same direction may be applied to each magnetoresistance effect element from the magnetic field applying mechanism. In addition, magnetization fixation directions of the magnetization fixed layers of the magnetoresistance effect elements can be the same direction.
In addition, the external magnetic field applied from the magnetic field applying mechanism has been described with an example in which in-plane direction components of each magnetoresistance effect element are provided. However, an angle (hereinafter referred to as a rotation angle) formed by an in-plane direction component in a direction of the external magnetic field applied from the magnetic field applying mechanism to each magnetoresistance effect element and an in-plane direction component in a fixation direction of the magnetization of the magnetization fixed layer of each magnetoresistance effect element is preferably around 90 degrees in that the amount of change in the resistance value of each magnetoresistance effect element due to the oscillation of the magnetization of the magnetization free layer of each magnetoresistance effect element becomes great, but it may be an acute angle or an obtuse angle. For example, in the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22, both rotation angles thereof may be 90 degrees, may be acute angles, or may be obtuse angles. Also, the rotation angle in the first magnetoresistance effect element 12 may be any one of an acute angle and an obtuse angle, and the rotation angle in the second magnetoresistance effect element 22 may be the other one of the acute angle and the obtuse angle. Also, the rotation angle in the first magnetoresistance effect element 12 may be either an acute angle or an obtuse angle, and the rotation angle in the second magnetoresistance effect element 22 may be 90 degrees. Also, the rotation angle in the first magnetoresistance effect element 12 may be 90 degrees, and the rotation angle in the second magnetoresistance effect element 22 may be either an acute angle or an obtuse angle.
Further, the external magnetic field applied from the magnetic field applying mechanism may have a stacking direction component of each magnetoresistance effect element. The angle (hereinafter referred to as an elevation angle) formed by the stacking direction component in a direction of the external magnetic field applied to each magnetoresistance effect element from the magnetic field applying mechanism and the in-plane direction component in the fixation direction of magnetization of the magnetization fixed layer of each magnetoresistance effect element (the in-plane direction of the magnetization fixed layer) may be an acute angle or an obtuse angle. For example, in the first magnetoresistance effect element 12 and the second magnetoresistance effect element 22, both the elevation angles may be acute angles or may be obtuse angles. Also, the elevation angle in the first magnetoresistance effect element 12 may be any one of an acute angle and an obtuse angle, and the elevation angle in the second magnetoresistance effect element 22 may be the other one of the acute angle and the obtuse angle.
<Other Uses>
In the above description, although the case where the magnetoresistance effect device is used as a high frequency filter has been presented as an example, the magnetoresistance effect device can also be used as a high frequency device such as an amplifier (amplifier).
Further, when the magnetoresistance effect device is used as an amplifier, the direct current or the direct current voltage applied from the power supply 90 is set to a predetermined magnitude or more. By doing so, the signal output from the second port 2 becomes larger than the signal input from the first port 1 and the magnetoresistance effect device functions as an amplifier.
As described above, the magnetoresistance effect device can function as a high frequency device such as an amplifier.
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