This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-034005, filed on Mar. 4, 2021; the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a magnetic sensor and an inspection device.
There is a magnetic sensor that uses a magnetic layer. There is an inspection device that uses the magnetic sensor. It is desirable to increase the sensitivity of the magnetic sensor.
According to one embodiment, a magnetic sensor includes a first sensor part. The first sensor part includes a first magnetic member, a first counter magnetic member, and a first magnetic element including one or a plurality of first extension parts. A direction from the first magnetic member toward the first counter magnetic member is along a first direction. The first extension part includes a first magnetic layer, a first counter magnetic layer, and a first nonmagnetic layer. The first magnetic layer includes a first portion, a first counter portion, and a first middle portion. A direction from the first portion toward the first counter portion is along the first direction. The first middle portion is between the first portion and the first counter portion. The first nonmagnetic layer is between the first counter magnetic layer and at least a portion of the first middle portion in a second direction crossing the first direction. An electrical resistance of the first magnetic element has a first value when a first magnetic field is applied to the first magnetic element. The electrical resistance has a second value when a second magnetic field is applied to the first magnetic element. The electrical resistance has a third value when a third magnetic field is applied to the first magnetic element. An absolute value of the first magnetic field is less than an absolute value of the second magnetic field and less than an absolute value of the third magnetic field. An orientation of the second magnetic field is opposite to an orientation of the third magnetic field. The first value is greater than the second value and greater than the third value.
According to one embodiment, an inspection device includes the magnetic sensor described above, and a processor configured to process a signal output from the magnetic sensor.
Exemplary embodiments will now be described with reference to the drawings.
The drawings are schematic or conceptual; and the relationships between the thickness and width of portions, the proportional coefficients of sizes among portions, etc., are not necessarily the same as the actual values thereof. Furthermore, the dimensions and proportional coefficients may be illustrated differently among drawings, even for identical portions.
In the specification of the application and the drawings, components similar to those described in regard to a drawing thereinabove are marked with like reference numerals, and a detailed description is omitted as appropriate.
As shown in
The direction from the first magnetic member 51 toward the first counter magnetic member 51A is along a first direction. The first direction is taken as an X-axis direction. One direction perpendicular to the X-axis direction is taken as a Z-axis direction. A direction perpendicular to the Z-axis direction and the X-axis direction is taken as a Y-axis direction.
The first magnetic element 11E includes one or multiple first extension parts 11x. In the example, the number of the first extension parts 11x is 1. As shown in
As shown in
The direction from the first portion p1 toward the first counter portion pA1 is along the first direction (the X-axis direction). The first middle portion pM1 is between the first portion p1 and the first counter portion pA1. The first nonmagnetic layer 11n is between the first counter magnetic layer 11o and at least a portion of the first middle portion pM1 in a second direction. The second direction crosses the first direction. The second direction is, for example, the Z-axis direction. The direction from the first portion p1 toward the first magnetic member 51 is along the second direction. The direction from the first counter portion pA1 toward the first counter magnetic member 51A is along the second direction.
As shown in
As shown in
The first middle portion pM1, the first nonmagnetic layer 11n, and the first counter magnetic layer 11o of the first magnetic layer 11 are used as, for example, a detecting part. The electrical resistance of the detecting part changes according to a magnetic field of a detection object.
According to the embodiment, a magnetic field (the external magnetic field of the detection object) is concentrated by the first magnetic member 51 and the first counter magnetic member 51A. The concentrated magnetic field can be efficiently applied to the first magnetic element 11E (the detecting part). For example, the first magnetic member 51 and the first counter magnetic member 51A function as a MFC (Magnetic Field Concentrator).
According to the embodiment, the first portion p1 of the first magnetic layer 11 overlaps the first magnetic member 51 in the Z-axis direction. The first counter portion pA1 of the first magnetic layer 11 overlaps the first counter magnetic member 51A in the Z-axis direction. Thereby, the concentrated magnetic field (external magnetic field) is efficiently applied to the first portion p1 and the first counter portion pA1. The concentrated magnetic field is more effectively applied to the first magnetic element 11E (the detecting part). High sensitivity is obtained thereby. According to the embodiment, for example, a magnetic sensor can be provided in which the sensitivity can be increased.
An example of the change of the electrical resistance of the first magnetic element 11E will now be described.
The horizontal axis of
As shown in
For example, the first magnetic field Hex1 is substantially 0. The electrical resistance Rx has a fourth value R4 when the external magnetic field Hex is not applied to the first magnetic element 11E. The first value R1 may be substantially equal to the fourth value R4 when the external magnetic field Hex is not applied. For example, the ratio of the absolute value of the difference between the first value R1 and the fourth value R4 to the fourth value R4 is not more than 0.01. A substantially even-function characteristic is obtained for the positive and negative external magnetic fields. By such a characteristic, the noise can be suppressed as described below, and high sensitivity is obtained. A magnetic sensor can be provided in which the sensitivity can be increased.
In the characteristic illustrated in
The horizontal axis of
In the magnetic sensor 110, for example, the change of the electrical resistance Rx of the first magnetic element 11E corresponds to the change of the angle between the orientation of the magnetization of the first magnetic layer 11 and the orientation of the magnetization of the first counter magnetic layer 11o.
For example, when the external magnetic field Hex is substantially 0, the orientation of the magnetization of the first magnetic layer 11 has a component in the opposite orientation of the orientation of the magnetization of the first counter magnetic layer 11o. For example, when the external magnetic field Hex is substantially 0, the orientation of the magnetization of the first magnetic layer 11 may be antiparallel to the orientation of the magnetization of the first counter magnetic layer 11o. In the antiparallel state, the angle between the orientation of the magnetization of the first magnetic layer 11 and the orientation of the magnetization of the first counter magnetic layer 11o is substantially 180 degrees. When the external magnetic field Hex is not 0, the angle between the orientation of the magnetization of the first magnetic layer 11 and the orientation of the magnetization of the first counter magnetic layer 11o is small. For example, these magnetizations change from the antiparallel alignment toward an orthogonal alignment. The characteristic illustrated in
A first conductive layer 11L may be provided as shown in
In the example as shown in
Another first conductive layer 11L that is electrically connected with the second counter magnetic layer 12o also may be provided.
The electrical resistance Rx of the first magnetic element 11E corresponds to the electrical resistance of a current path including the first counter magnetic layer 11, the first nonmagnetic layer 11n, the first magnetic layer 11, the second nonmagnetic layer 12n, and the second counter magnetic layer 12o. The electrical resistance Rx of the first magnetic element 11E corresponds to the electrical resistance between the first conductive layer 11L that is electrically connected with the first counter magnetic layer 110 and the other first conductive layer 11L that is electrically connected with the second counter magnetic layer 12o.
As shown in
As shown in
As shown in
The length along the first direction (the X-axis direction) of the first nonmagnetic layer 11n is taken as a first nonmagnetic layer length L11n. It is favorable for the first nonmagnetic layer length L11n to be, for example, not more than the first distance g1. Higher sensitivity is easily obtained thereby.
The length along the first direction (the X-axis direction) of the first portion p1 is taken as a first portion length Lp1. The first portion length Lp1 corresponds to the length of a region that overlaps the first magnetic member 51 of the first magnetic layer 11. In one example, it is favorable for the first portion length Lp1 to be greater than the first distance g1. High sensitivity is easily obtained. The length along the first direction (the X-axis direction) of the first counter portion pA1 is taken as a first counter portion length LpA1. The first counter portion length LpA1 corresponds to the length of a region that overlaps the first counter magnetic member 51A of the first magnetic layer 11. In one example, it is favorable for the first counter portion length LpA1 to be greater than the first distance gi. High sensitivity is easily obtained.
As shown in
As shown in
For example, the magnetization of the first magnetic layer 11 may be controlled by the first layer 11Ma. For example, the magnetization of the first magnetic layer 11 may be along the Y-axis direction. The orientation of the magnetization of the first magnetic layer 11 has an opposite-direction component of the orientation of the magnetization of the first counter magnetic layer 110.
As shown in
For example, the second layer 11Mb includes an alloy including Ag and Sn, an alloy including Ag and Mg, an alloy including Ag and In, or an alloy including Ag and Ga.
For example, the magnetization of the first magnetic layer 11 is favorably controlled by the first and second layers 11Ma and 11 Mb. For example, the magnetization of the intermediate layer 11Mm is controlled to be in one direction by the first layer 11Ma. Ferromagnetic coupling between the intermediate layer 11Mm and the first magnetic layer 11 exists via the second layer 11Mb. Thereby, the direction of the magnetization of the first magnetic layer 11 is controlled to be along the direction of the magnetization of the intermediate layer 11Mm.
As shown in
As shown in
In the first extension part 11x as shown in
As shown in
According to the embodiment, the first nonmagnetic layer 11n and the second nonmagnetic layer 12n may be nonmagnetic. The first nonmagnetic layer 11n and the second nonmagnetic layer 12n include, for example, an oxide. The first nonmagnetic layer 11n and the second nonmagnetic layer 12n include, for example, MgO. A high MR ratio is obtained. For example, the first magnetic element 11E (the detecting part) is, for example, a MTJ (Magnetic tunnel junction) element.
The first counter magnetic layer 11o and the second counter magnetic layer 12o include, for example, at least one selected from the group consisting of Fe, Co, and Ni. The first magnetic layer 11 includes, for example, Fe, Co, B, and Ta. In one example, the first magnetic layer 11 includes, for example, a stacked body that includes a layer including Fe, Co, B, and Ta, a Ta layer, and a CoFeN layer. These layers are stacked along the Z-axis direction. The first magnetic layer 11, the first counter magnetic layer 110, the second counter magnetic layer 12o, the fourth layer 11Md, and the other fourth layer 12Md are, for example, ferromagnetic layers. The first magnetic member 51 and the first counter magnetic member 51A include, for example, at least one selected from the group consisting of NiFe and FeAlSi. The first magnetic member 51 and the first counter magnetic member 51A are, for example, soft magnetic materials. The relative magnetic permeabilities of the first magnetic member 51 and the first counter magnetic member 51A are, for example, not less than 1000.
As shown in
The multiple first extension parts lix are arranged in the third direction. The third direction crosses a plane (the X-Z plane) including the first and second directions. The third direction is, for example, the Y-axis direction.
As shown in
As shown in
For example, the detecting parts that are included in the multiple first extension parts 11x are electrically connected in series. For example, noise is suppressed. For example, an electrical resistance that is suited to the detection is obtained. Higher sensitivity is easily obtained.
Each of the multiple first extension parts 11x may have a configuration similar to the configuration of the first extension part 11x illustrated in
As shown in
At least a portion of the first corresponding portion 21 overlaps the region 66a between the first magnetic member 51 and the first counter magnetic member 51A in the second direction (the Z-axis direction). A first current I1 that includes an alternating current component can flow in the first corresponding portion 21. The first current I1 flows through the first corresponding portion 21 along the third direction. The third direction crosses a plane (the Z-X plane) including the first and second directions. The third direction is, for example, the Y-axis direction.
The magnetic sensor 112 may include a first current circuit 71. The first current circuit 71 is configured to supply the first current I1 to the conductive member 20. The first current circuit 71 is configured to supply the first current I1 to the first corresponding portion 21. The first current circuit 71 may be included in the controller 70.
For example, the first corresponding portion 21 includes a first conductive portion 21e and a first other-conductive portion 21f. For example, the first conductive portion 21e overlaps the first end portion 11Ee in the Z-axis direction. For example, the first other-conductive portion 21f overlaps the first other-end portion 11Ef in the Z-axis direction. The first current circuit 71 is electrically connected with the first conductive portion 21e and the first other-conductive portion 21f. The first current I1 flows between the first conductive portion 21e and the first other-conductive portion 21f. The direction from the first conductive portion 21e toward the first other-conductive portion 21f is along the Y-axis direction.
Because the first current I1 that includes an alternating current component flows in the first corresponding portion 21, a magnetic field (an alternating current magnetic field) based on the first current I1 is applied to the detecting part of the first magnetic element 11E. The alternating current magnetic field includes, for example, a component along the X-axis direction. The alternating current magnetic field is concentrated by the first magnetic member 51 and the first counter magnetic member 51A. The concentrated alternating current magnetic field is applied to the detecting part. The alternating current magnetic field is efficiently applied to the detecting part. As described below, unnecessary noise is suppressed by using the alternating current magnetic field. Higher sensitivity is obtained.
The horizontal axis of
For example, the electrical resistance Rx of the first magnetic element 11E has the first value R1 when a first-value current Ia1 is supplied to the conductive member 20 (the first corresponding portion 21). The electrical resistance Rx has the second value R2 when a second-value current Ia2 is supplied to the conductive member 20 (the first corresponding portion 21). The electrical resistance Rx has the third value R3 when a third-value current Ia3 is supplied to the conductive member 20 (the first corresponding portion 21). The absolute value of the first-value current Ia1 is less than the absolute value of the second-value current Ia2 and less than the absolute value of the third-value current Ia3. The first-value current Ia1 may be, for example, substantially 0. The orientation of the second-value current Ia2 is opposite to the orientation of the third-value current Ia3. The first value R1 is greater than the second value R2 and greater than the third value R3.
For example, the first-value current Ia1 is substantially 0. For example, the electrical resistance Rx has the fourth value R4 when a current does not flow in the first corresponding portion 21. For example, the first value R1 is substantially equal to the fourth value R4 when the current does not flow. For example, the ratio of the absolute value of the difference between the first value R1 and the fourth value R4 to the fourth value R4 is not more than 0.01. The ratio may be not more than 0.001. A substantially even-function characteristic is obtained for the positive and negative currents.
By utilizing such an even-function characteristic, highly-sensitive detection is possible as follows.
An example will now be described in which the first current I1 is an alternating current and substantially does not include a direct current component. The first current I1 (the alternating current) is supplied to the first corresponding portion 21; and an alternating current magnetic field due to the alternating current is applied to the first magnetic element 11E. An example of the change of the electrical resistance Rx at this time will now be described.
As shown in
As shown in
As shown in
Change in the resistance R is different for the positive and negative of the alternating current magnetic field Hac when a signal magnetic field Hsig with non-zero magnitude is applied. The period of the change of the resistance R with respect to the positive and negative of the alternating current magnetic field Hac is equal to the period of the alternating current magnetic field Hac. An output voltage that has an alternating current frequency component corresponding to the signal magnetic field Hsig is generated.
The characteristics described above are obtained in the case where the signal magnetic field Hsig does not temporally change. The case where the signal magnetic field Hsig temporally changes is as follows. The frequency of the signal magnetic field Hsig is taken as a signal frequency fsig. The frequency of the alternating current magnetic field Hac is taken as an alternating current frequency fac. In such a case, an output that corresponds to the signal magnetic field Hsig is generated at the frequency of fac±fsig.
In the case where the signal magnetic field Hsig temporally changes, the signal frequency fsig is, for example, not more than 1 kHz. On the other hand, the alternating current frequency fac is sufficiently greater than the signal frequency fsig. For example, the alternating current frequency fac is not less than 10 times the signal frequency fsig.
For example, the signal magnetic field Hsig can be detected with high accuracy by extracting an output voltage having the same period (frequency) component (alternating current frequency component) as the period (the frequency) of the alternating current magnetic field Hac. In the magnetic sensor (the magnetic sensor 112 or the magnetic sensor 113) according to the embodiment, the external magnetic field Hex (the signal magnetic field Hsig) that is the detection object can be detected with high sensitivity by utilizing such characteristics According to the embodiment, the external magnetic field Hex (the signal magnetic field Hsig) and the alternating current magnetic field Hac due to the first current I1 can be efficiently applied to the first magnetic element 11E by the first magnetic member 51 and the first counter magnetic member 51A. High sensitivity is obtained.
In the magnetic sensor 113 according to the embodiment as shown in
In the magnetic sensor 113 as well, at least a portion of the first corresponding portion 21 overlaps the region 66a between the first magnetic member 51 and the first counter magnetic member 51A in the second direction (the Z-axis direction). The first current I1 that includes the alternating current component can flow in the first corresponding portion 21 along the third direction (the Y-axis direction). The alternating current magnetic field based on the first current I1 is concentrated by the first magnetic member 51 and the first counter magnetic member 51A. The concentrated alternating current magnetic field is efficiently applied to the detecting part. Higher sensitivity is obtained.
In the magnetic sensor (e.g., the magnetic sensors 110 to 113, etc.) according to the first embodiment, the electrical resistance of the first magnetic element 11E has an even-function characteristic with respect to the magnetic field applied to the first magnetic element 11E. The magnetic field includes, for example, the external magnetic field of the detection object. The magnetic field may include a magnetic field (an alternating current magnetic field) based on the first current I1 that includes an alternating current component. For example, the electrical resistance of the first magnetic element 11E has an even-function characteristic with respect to the first current I1 supplied to the first corresponding portion 21. As described above, the magnetic field includes a component along the X-axis direction.
In the magnetic sensor 113 as well, the electrical resistance Rx may have characteristics similar to the characteristics described for the magnetic sensor 112. In the magnetic sensors 111 to 113, the first extension part 11x may have the configuration described with reference to
As shown in
The first counter magnetic member 51A is between the first magnetic member 51 and the other first counter magnetic member 51B in the first direction (the X-axis direction).
As shown in
As shown in
The electrical resistance of the first magnetic element 11E corresponds to the electrical resistance of a current path that includes the first magnetic layer 11, the first counter magnetic layer 110, the first nonmagnetic layer 11n, the second nonmagnetic layer 12n, and the second counter magnetic layer 12o.
In the example as shown in
As shown in
For example, the first counter magnetic layer 11o of the other one of the multiple first extension parts 11x is the first end portion 11Ee of the first magnetic element 11E. The first counter magnetic layer 110 of the one of the multiple first extension parts 11x is the first other-end portion 11Ef of the first magnetic element 11E.
As shown in
In the magnetic sensor 115 according to the embodiment as shown in
In the magnetic sensor 115, in the second direction (the Z-axis direction), the first corresponding portion 21 overlaps the region 66a between the first magnetic member 51 and the first counter magnetic member 51A and a region 66aA between the first counter magnetic member 51A and the other first counter magnetic member 51B.
The first current circuit 71 is electrically connected with the first conductive portion 21e of the first corresponding portion 21 and the first other-conductive portion 21f of the first corresponding portion 21. The first current I1 that includes an alternating current component is supplied from the first current circuit 71 to the first corresponding portion 21.
As shown in
The second to fourth magnetic elements 12E to 14E each may have the configuration of the first magnetic element 11E. In the example, these magnetic elements have the configuration of the first magnetic element 11E of the magnetic sensor 113.
The first magnetic element 11E includes the first end portion 11Ee and the first other-end portion 11Ef. The second magnetic element 12E includes a second end portion 12Ee and a second other-end portion 12Ef. The third magnetic element 13E includes a third end portion 13Ee and a third other-end portion 13Ef. The fourth magnetic element 14E includes a fourth end portion 14Ee and a fourth other-end portion 14Ef.
In the example, the first end portion 11Ee is electrically connected with the third end portion 13Ee. The first other-end portion 11Ef is electrically connected with the second end portion 12Ee. The third other-end portion 13Ef is electrically connected with the fourth end portion 14Ee. The second other-end portion 12Ef is electrically connected with the fourth other-end portion 14Ef.
As shown in
As shown in
The first to fourth magnetic elements 11E to 14E have a bridge connection. The change of the potential between two midpoints (the third connection point CP3 and the fourth connection point CP4) of the bridge circuit is detected by the detection circuit 73. The detection can have higher sensitivity due to the bridge circuit.
In the magnetic sensor 120, the conductive member 20 includes the first corresponding portion 21. As described above, at least a portion of the first corresponding portion 21 overlaps the region 66a between the first magnetic member 51 and the first counter magnetic member 51A in the second direction (the Z-axis direction).
As shown in
As shown in
As shown in
The first corresponding portion 21 includes the first conductive portion 21e and the first other-conductive portion 21f. The second corresponding portion 22 includes a second conductive portion 22e and a second other-conductive portion 22f. The third corresponding portion 23 includes a third conductive portion 23e and a third other-conductive portion 23f. The fourth corresponding portion 24 includes a fourth conductive portion 24e and a fourth other-conductive portion 24f.
For example, the first conductive portion 21e overlaps the first end portion 11Ee in the Z-axis direction. For example, the first other-conductive portion 21f overlaps the first other-end portion 11Ff in the Z-axis direction. For example, the second conductive portion 22e overlaps the second end portion 12Fe in the Z-axis direction. For example, the second other-conductive portion 22f overlaps the second other-end portion 12Ef in the Z-axis direction. For example, the third conductive portion 23e overlaps the third end portion 13Ee in the Z-axis direction. For example, the third other-conductive portion 23f overlaps the third other-end portion 13Ff in the Z-axis direction. For example, the fourth conductive portion 24e overlaps the fourth end portion 14Ee in the Z-axis direction. For example, the fourth other-conductive portion 24f overlaps the fourth other-end portion 14Ef in the Z-axis direction.
In the example as shown in
As shown in
For example, one time when the first current I1 is supplied to the conductive member 20 is taken as a first time. At the first time, the element current Id flows through the first magnetic element 11E in the orientation from the first end portion 11Ee toward the first other-end portion 11Ef. At the first time, the element current Id flows through the second magnetic element 12E in the orientation from the second end portion 12Ee toward the second other-end portion 12Ef. At the first time, the element current Id flows through the third magnetic element 13E in the orientation from the third end portion 13Ee toward the third other-end portion 13Ef. At the first time, the element current Id flows through the fourth magnetic element 14E in the orientation from the fourth end portion 14Ee toward the fourth other-end portion 14Ef.
At the first time, the first current I1 flows through the first corresponding portion 21 in the orientation from the first other-conductive portion 21f toward the first conductive portion 21e. At the first time, the first current I1 flows through the second corresponding portion 22 in the orientation from the second conductive portion 22e toward the second other-conductive portion 22f. At the first time, the first current I1 flows through the third corresponding portion 23 in the orientation from the third conductive portion 23e toward the third other-conductive portion 23f. At the first time, the first current I1 flows through the fourth corresponding portion 24 in the orientation from the fourth other-conductive portion 24f toward the fourth conductive portion 24e.
The relationship (the phase) between the orientation of the current flowing in the first magnetic element 11E and the orientation of the current flowing in the first corresponding portion 21 in the first sensor part 10A is opposite to the relationship (the phase) between the orientation of the current flowing in the third magnetic element 13E and the orientation of the current flowing in the third corresponding portion 23 in the third sensor part 10C. The relationship (the phase) between the orientation of the current flowing in the second magnetic element 12E and the orientation of the current flowing in the second corresponding portion 22 in the second sensor part 10B is opposite to the relationship (the phase) between the orientation of the current flowing in the fourth magnetic element 14E and the orientation of the current flowing in the fourth corresponding portion 24 in the fourth sensor part 10D. The relationship (the phase) between the orientation of the current flowing in the first magnetic element 11E and the orientation of the current flowing in the first corresponding portion 21 in the first sensor part 10A is opposite to the relationship (the phase) between the orientation of the current flowing in the second magnetic element 12E and the orientation of the current flowing in the second corresponding portion 22 in the second sensor part 10B.
For example, as shown in
For example, as shown in
For example, as shown in
The second magnetic element 12E, the third magnetic element 13E, and the fourth magnetic element 14E may have configuration similar to the first magnetic element 11E. The electrical resistances of the second magnetic element 12E, the third magnetic element 13E, and the fourth magnetic element 14E may have characteristics similar to the electrical resistance Rx of the first magnetic element 11E.
A fourth embodiment relates to an inspection device. As described below, the inspection device may include a diagnostic device.
As shown in
In the example, the inspection device 550 includes a magnetic field application part 76A. The magnetic field application part 76A is configured to apply a magnetic field to a detection object 80. The detection object 80 is, for example, the inspection object. The detection object 80 includes at least an inspection conductive member 80c such as a metal, etc. For example, an eddy current is generated in the inspection conductive member 80c when the magnetic field due to the magnetic field application part 76A is applied to the inspection conductive member 80c. The state of the eddy current changes when there is a flaw or the like in the inspection conductive member 80c. The state (e.g., the flaw, etc.) of the inspection conductive member 80c can be inspected by the magnetic sensor (e.g., the magnetic sensor 110, etc.) detecting the magnetic field due to the eddy current. The magnetic field application part 76A is, for example, an eddy current generator.
In the example, the magnetic field application part 76A includes an application control circuit part 76a, a drive amplifier 76b, and a coil 76c. A current is supplied to the drive amplifier 76b by the control by the application control circuit part 76a. The current is, for example, an alternating current. The frequency of the current is, for example, an eddy current excitation frequency. The eddy current excitation frequency is, for example, not less than 10 Hz and not more than 100 kHz. The eddy current excitation frequency may be, for example, less than 100 kHz.
For example, information (which may be, for example, a signal) that relates to the frequency of the alternating current component of the first current I1 is supplied from the sensor control circuit part 75c to the first lock-in amplifier 75a as a reference wave (a reference signal). The output of the first lock-in amplifier 75a is supplied to the second lock-in amplifier 75b. Information (which may be, for example, a signal) that relates to the eddy current excitation frequency is supplied from the application control circuit part 76a to the second lock-in amplifier 75b as a reference wave (a reference signal). The second lock-in amplifier 75b is configured to output a signal component corresponding to the eddy current excitation frequency.
Thus, for example, the processor 78 includes the first lock-in amplifier 75a. The output signal SigX that is obtained from the magnetic sensor 110 and a signal SigR1 that corresponds to the frequency of the alternating current component included in the first current I1 are input to the first lock-in amplifier 75a. The first lock-in amplifier 75a is configured to output an output signal SigX1 that uses the signal SigR1 corresponding to the frequency of the alternating current component included in the first current I1 as a reference wave (a reference signal). By providing the first lock-in amplifier 75a, it is possible to suppress noise and detect with high sensitivity.
The processor 78 may further include the second lock-in amplifier 75b. The output signal SigX1 of the first lock-in amplifier 75a and a signal SigR2 that corresponds to the frequency (the eddy current excitation frequency) of the supply signal (in the example, the magnetic field due to the magnetic field application part 76A) supplied toward the detection object 80 (the inspection object) are input to the second lock-in amplifier 75b. The second lock-in amplifier 75b is configured to output an output signal SigX2 that uses the signal SigR2 corresponding to the frequency of the supply signal supplied toward the detection object 80 (the inspection object) as a reference wave (a reference signal). By providing the second lock-in amplifier 75b, it is possible to further suppress noise and detect with even higher sensitivity.
An abnormality such as a flaw or the like of the inspection conductive member 80c of the detection object 80 can be inspected by the inspection device 550.
As shown in
In the example, the detection object driver 76B includes the application control circuit part 76a and the drive amplifier 76b. The drive amplifier 76b is controlled by the application control circuit part 76a; and a current is supplied from the drive amplifier 76b to the inspection conductive member 80c. The current is, for example, an alternating current. For example, the alternating current is supplied to the inspection conductive member 80c. The frequency of the alternating current is, for example, not less than 10 Hz and not more than 100 kHz. The frequency may be, for example, less than 100 kHz. In the example as well, for example, by providing the first lock-in amplifier 75a and the second lock-in amplifier 75b, it is possible to suppress noise and detect with high sensitivity. In one example of the inspection device 551, multiple magnetic sensors (e.g., the multiple magnetic sensors 110) may be provided. The multiple magnetic sensors are, for example, a sensor array. The inspection conductive member 80c can be inspected in a short period of time by the sensor array. In one example of the inspection device 551, the inspection conductive member 80c may be inspected by scanning the magnetic sensor (e.g., the magnetic sensor 110).
As shown in
For example, an inspection object 680 is inspected by the inspection device 710. The inspection object 680 is, for example, an electronic device (including a semiconductor circuit, etc.). The inspection object 680 may be, for example, a battery 610, etc.
For example, the magnetic sensor 150a according to the embodiment may be used together with the battery 610. For example, a battery system 600 includes the battery 610 and the magnetic sensor 150a. The magnetic sensor 150a can detect a magnetic field generated by a current flowing in the battery 610.
As shown in
The magnetic sensor 150a can detect a magnetic field generated by a current flowing in the inspection object 680 (which may be, for example, the battery 610). For example, an abnormal current flows in the battery 610 when the battery 610 approaches an abnormal state. The change of the state of the battery 610 can be known by the magnetic sensor 150a detecting the abnormal current. For example, the entire battery 610 can be inspected in a short period of time by moving the sensor array in two directions while the magnetic sensor 150a is proximate to the battery 610. The magnetic sensor 150a may be used to inspect the battery 610 in the manufacturing process of the battery 610.
For example, the magnetic sensor according to the embodiment is applicable to the inspection device 710 such as a diagnostic device, etc.
As shown in
In the diagnostic device 500, the magnetic sensor 150 is, for example, a magnetoencephalography device. The magnetoencephalography device detects a magnetic field generated by cranial nerves. When the magnetic sensor 150 is included in a magnetoencephalography device, the size of the magnetic element included in the magnetic sensor 150 is, for example, not less than 1 mm but less than 10 mm. The size is, for example, the length including the MFC.
As shown in
The magnetic sensor 150 may include, for example, a circuit for differential detection, etc. The magnetic sensor 150 may include a sensor other than a magnetic sensor (e.g., a potential terminal, an acceleration sensor, etc.).
The size of the magnetic sensor 150 is small compared to the size of a conventional SQUID magnetic sensor. Therefore, the mounting of the multiple sensor parts 301 is easy. The mounting of the multiple sensor parts 301 and the other circuits is easy. The multiple sensor parts 301 and the other sensors can be easily mounted together.
The base body 302 may include, for example, an elastic body such as a silicone resin, etc. For example, the multiple sensor parts 301 are linked to each other and provided in the base body 302. For example, the base body 302 can be closely adhered to the head.
An input/output cord 303 of the sensor part 301 is connected with a sensor driver 506 and a signal input/output part 504 of the diagnostic device 500. A magnetic field measurement is performed in the sensor part 301 based on electrical power from the sensor driver 506 and a control signal from the signal input/output part 504. The result is input to the signal input/output part 504. The signal that is obtained by the signal input/output part 504 is supplied to a signal processor 508. Processing such as, for example, the removal of noise, filtering, amplification, signal calculation, etc., are performed in the signal processor 508. The signal that is processed by the signal processor 508 is supplied to a signal analyzer 510. For example, the signal analyzer 510 extracts a designated signal for magnetoencephalography. For example, signal analysis to match the signal phases is performed in the signal analyzer 510.
The output of the signal analyzer 510 (the data for which the signal analysis is finished) is supplied to a data processor 512. Data analysis is performed in the data processor 512. It is possible to include image data such as, for example, MRI (Magnetic Resonance Imaging), etc., in the data analysis. It is possible to include, for example, scalp potential information such as EEG (Electroencephalogram), etc., in the data analysis. For example, a data part 514 of the MRI, the EEG, etc., is connected with the data processor 512. For example, nerve firing point analysis, inverse analysis, or the like is performed by the data analysis.
For example, the result of the data analysis is supplied to an imaging diagnostic part 516. Imaging is performed by the imaging diagnostic part 516. The diagnosis is supported by the imaging.
For example, the series of operations described above is controlled by a control mechanism 502. For example, necessary data such as preliminary signal data, metadata partway through the data processing, or the like is stored in a data server. The data server and the control mechanism may be integrated.
The diagnostic device 500 according to the embodiment includes the magnetic sensor 150, and a processor that processes the output signal obtained from the magnetic sensor 150. The processor includes, for example, at least one of the signal processor 508 or the data processor 512. The processor includes, for example, a computer, etc.
In the magnetic sensor 150 shown in
It is favorable for the magnetic sensor device including the participant to be mounted inside a shielded room. For example, the effects of geomagnetism or magnetic noise can be suppressed thereby.
For example, a mechanism may be provided to locally shield the sensor part 301 or the measurement section of the human body. For example, a shield mechanism may be provided in the sensor part 301. For example, the signal analysis or the data processing may be effectively shielded.
According to the embodiment, the base body 302 may be flexible or may be substantially not flexible. In the example shown in
The input and output of the signal obtained from the sensor part 301 in the example shown in
There is a reference example in which a SQUID (Superconducting Quantum Interference Device) magnetic sensor is used as a device to measure a faint magnetic field such as a magnetic field emitted from a living body, etc. Because superconductivity is used in the reference example, the device is large; and the power consumption is large. The load on the measurement object (the patient) is large.
According to the embodiment, the device can be small. The power consumption can be suppressed. The load on the measurement object (the patient) can be reduced. According to the embodiment, the SN ratio of the magnetic field detection can be improved. The sensitivity can be increased.
Embodiments may include the following configurations (e.g., technological proposals).
A magnetic sensor, comprising:
a first sensor part including
the first extension part including a first magnetic layer, a first counter magnetic layer, and a first nonmagnetic layer,
the first magnetic layer including a first portion, a first counter portion, and a first middle portion,
a direction from the first portion toward the first counter portion being along the first direction,
the first middle portion being between the first portion and the first counter portion,
the first nonmagnetic layer being between the first counter magnetic layer and at least a portion of the first middle portion in a second direction crossing the first direction,
an electrical resistance of the first magnetic element having a first value when a first magnetic field is applied to the first magnetic element,
the electrical resistance having a second value when a second magnetic field is applied to the first magnetic element,
the electrical resistance having a third value when a third magnetic field is applied to the first magnetic element,
an absolute value of the first magnetic field being less than an absolute value of the second magnetic field and less than an absolute value of the third magnetic field,
an orientation of the second magnetic field being opposite to an orientation of the third magnetic field,
the first value being greater than the second value and greater than the third value.
The magnetic sensor according to Configuration 1, wherein
the electrical resistance of the first magnetic element has an even-function characteristic with respect to a magnetic field applied to the first magnetic element.
The magnetic sensor according to Configuration 1 or 2, wherein
the first magnetic layer includes Fe, Co, B, and Ta.
The magnetic sensor according to any one of Configurations 1 to 3, wherein
the first extension part further includes a first layer,
the first layer includes at least one selected from the group consisting of IrMn and PtMn, and
the first magnetic layer is located between the first layer and the first nonmagnetic layer.
The magnetic sensor according to Configuration 4, wherein
the first extension part further includes:
the intermediate layer includes at least one selected from the group consisting of Fe, Co, and Ni.
The magnetic sensor according to Configuration 5, wherein
the second layer includes at least one selected from the group consisting of Ag and Cu.
The magnetic sensor according to any one of Configurations 1 to 6, wherein
the first extension part further includes a third layer and a fourth layer,
the first counter magnetic layer is located between the first magnetic layer and the fourth layer,
the third layer is located between the first counter magnetic layer and the fourth layer,
the third layer includes Ru, and
the fourth layer includes at least one selected from the group consisting of Fe, Co, and Ni.
The magnetic sensor according to Configuration 7, wherein
the first extension part further includes a fifth layer,
the fifth layer includes at least one selected from the group consisting of IrMn and PtMn,
the first counter magnetic layer is located between the first magnetic layer and the fifth layer, and
the fourth layer is located between the first counter magnetic layer and the fifth layer.
The magnetic sensor according to any one of Configurations 1 to 8, wherein
the first nonmagnetic layer includes an oxide.
The magnetic sensor according to any one of Configurations 1 to 9, wherein
the first nonmagnetic layer is insulative.
The magnetic sensor according to any one of Configurations 1 to 10, further comprising:
a conductive member including a first corresponding portion,
at least a portion of the first corresponding portion overlapping a region between the first magnetic member and the first counter magnetic member in the second direction,
a first current including an alternating current component and being able to flow in the first corresponding portion,
the first current flowing through the first corresponding portion along a third direction,
the third direction crossing a plane including the first and second directions.
The magnetic sensor according to any one of Configurations 1 to 10, wherein
the first extension part includes a second counter magnetic layer and a second nonmagnetic layer,
the first nonmagnetic layer is between the first counter magnetic layer and a portion of the first middle portion in the second direction,
the second nonmagnetic layer is between the second counter magnetic layer and an other portion of the first middle portion in the second direction,
a direction from the second nonmagnetic layer toward the first nonmagnetic layer is along a third direction, and
the third direction crosses a plane including the first and second directions.
The magnetic sensor according to Configuration 12, wherein
the first magnetic element includes the plurality of first extension parts,
the plurality of first extension parts is arranged along the third direction, and
the third direction crosses the plane including the first and second directions.
The magnetic sensor according to Configuration 13, wherein
the first magnetic element further includes a first connection member, and
the first connection member electrically connects the second counter magnetic layer of one of the plurality of first extension parts and the first counter magnetic layer of an other one of the plurality of first extension parts.
The magnetic sensor according to any one of Configurations 1 to 10, wherein
the first sensor part further includes an other first counter magnetic member,
the first counter magnetic member is between the first magnetic member and the other first counter magnetic member in the first direction,
the first extension part further includes a second counter magnetic layer and a second nonmagnetic layer,
the first magnetic layer further includes a second counter portion and a second middle portion,
the first counter portion is between the first portion and the second counter portion in the first direction,
the second middle portion is between the first counter portion and the second counter portion, and
the second nonmagnetic layer is between the second counter magnetic layer and at least a portion of the second middle portion in the second direction.
The magnetic sensor according to Configuration 15, wherein
the first magnetic element includes the plurality of first extension parts and a first connection member,
the plurality of first extension parts is arranged along a third direction,
the third direction crosses a plane including the first and second directions, and
the first connection member electrically connects the second counter magnetic layer of one of the plurality of first extension parts and the second counter magnetic layer of an other one of the plurality of first extension parts.
The magnetic sensor according to Configuration 11, further comprising:
a second sensor part including a second magnetic element;
a third sensor part including a third magnetic element;
a fourth sensor part including a fourth magnetic element; and
an element current circuit,
the first magnetic element including a first end portion and a first other-end portion,
the second magnetic element including a second end portion and a second other-end portion,
the third magnetic element including a third end portion and a third other-end portion,
the fourth magnetic element including a fourth end portion and a fourth other-end portion,
the first end portion being electrically connected with the third end portion,
the first other-end portion being electrically connected with the second end portion,
the third other-end portion being electrically connected with the fourth end portion,
the second other-end portion being electrically connected with the fourth other-end portion,
the element current circuit being configured to supply an element current between a first connection point and a second connection point,
the first connection point being between the first end portion and the third end portion,
the second connection point being between the second other-end portion and the fourth other-end portion.
The magnetic sensor according to Configuration 17, wherein
the second sensor part includes a second magnetic member and a second counter magnetic member,
the third sensor part includes a third magnetic member and a third counter magnetic member,
the fourth sensor part includes a fourth magnetic member and a fourth counter magnetic member,
the conductive member further includes a second corresponding portion, a third corresponding portion, and a fourth corresponding portion,
at least a portion of the second corresponding portion overlaps a region between the second magnetic member and the second counter magnetic member in the second direction,
at least a portion of the third corresponding portion overlaps a region between the third magnetic member and the third counter magnetic member in the second direction,
at least a portion of the fourth corresponding portion overlaps a region between the fourth magnetic member and the fourth counter magnetic member in the second direction,
the first corresponding portion includes a first conductive portion and a first other-conductive portion,
the second corresponding portion includes a second conductive portion and a second other-conductive portion,
the third corresponding portion includes a third conductive portion and a third other-conductive portion,
the fourth corresponding portion includes a fourth conductive portion and a fourth other-conductive portion, and
at a first time when the first current is supplied to the conductive member:
The magnetic sensor according to Configuration 18, further comprising:
a first current circuit configured to supply the first current to the conductive member,
the first end portion being electrically connected with the third end portion,
the first other-end portion being electrically connected with the second end portion,
the third other-end portion being electrically connected with the fourth end portion,
the second other-end portion being electrically connected with the fourth other-end portion,
the first current circuit being configured to supply the first current between a fifth connection point and a sixth connection point,
the fifth connection point being between the first other-end portion and the second end portion,
the sixth connection point being between the third other-end portion and the fourth end portion.
An inspection device, comprising:
the magnetic sensor according to any one of Configurations 1 to 19; and
a processor configured to process a signal output from the magnetic sensor.
According to embodiments, a magnetic sensor and an inspection device can be provided in which the sensitivity can be increased.
In the specification of the application, “perpendicular” and “parallel” refer to not only strictly perpendicular and strictly parallel but also include, for example, the fluctuation due to manufacturing processes, etc. It is sufficient to be substantially perpendicular and substantially parallel.
Hereinabove, exemplary embodiments of the invention are described with reference to specific examples. However, the embodiments of the invention are not limited to these specific examples. For example, one skilled in the art may similarly practice the invention by appropriately selecting specific configurations of components included in magnetic sensors such as sensor parts, magnetic elements, magnetic layers, nonmagnetic layers, magnetic members, circuits, etc., from known art. Such practice is included in the scope of the invention to the extent that similar effects thereto are obtained.
Further, any two or more components of the specific examples may be combined within the extent of technical feasibility and are included in the scope of the invention to the extent that the purport of the invention is included.
Moreover, all magnetic sensors, and inspection devices practicable by an appropriate design modification by one skilled in the art based on the magnetic sensors, and the inspection devices described above as embodiments of the invention also are within the scope of the invention to the extent that the purport of the invention is included.
Various other variations and modifications can be conceived by those skilled in the art within the spirit of the invention, and it is understood that such variations and modifications are also encompassed within the scope of the invention.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.
Number | Date | Country | Kind |
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2021-034005 | Mar 2021 | JP | national |