This application is based upon and claims the benefit of priority from Japanese Patent Application No.2019-163030, filed on Sep. 6, 2019; the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a magnetic head and a magnetic recording device.
Information is recorded in a magnetic storage medium such as a HDD (Hard Disk Drive) or the like by using a magnetic head. It is desirable to increase the recording density of the magnetic head and the magnetic recording device.
According to one embodiment, a magnetic head includes a magnetic pole, a first shield, a first magnetic layer, a second magnetic layer, a third magnetic layer, a first intermediate layer, a second intermediate layer, a third intermediate layer, and a fourth intermediate layer. The first magnetic layer is provided between the magnetic pole and the first shield. The second magnetic layer is provided between the first magnetic layer and the first shield. The third magnetic layer is provided between the second magnetic layer and the first shield. The first intermediate layer is provided between the magnetic pole and the first magnetic layer. The first intermediate layer includes at least one selected from a first group consisting of Au, Cu, Ag, Al, and Ti. The second intermediate layer is provided between the first magnetic layer and the second magnetic layer. The second intermediate layer includes at least one selected from a second group consisting of Ta, Ir, W, Mo, Cr, Tb, Rh, and Pd. The third intermediate layer includes at least one selected from the first group and is provided between the second magnetic layer and the third magnetic layer. The fourth intermediate layer includes at least one selected from the second group and is provided between the third magnetic layer and the first shield.
Various embodiments are described below with reference to the accompanying drawings.
The drawings are schematic and conceptual; and the relationships between the thickness and width of portions, the proportions of sizes among portions, etc., are not necessarily the same as the actual values. The dimensions and proportions may be illustrated differently among drawings, even for identical portions.
In the specification and drawings, components similar to those described previously or illustrated in an antecedent drawing are marked with like reference numerals, and a detailed description is omitted as appropriate.
As shown in
The magnetic recording medium 80 includes, for example, a medium substrate 82, and a magnetic recording layer 81 provided on the medium substrate 82. A magnetization 83 of the magnetic recording layer 81 is controlled by the recording portion 60.
The reproducing portion 70 includes, for example, a first reproduction magnetic shield 72a, a second reproduction magnetic shield 72b, and a magnetic reproducing element 71. The magnetic reproducing element 71 is provided between the first reproduction magnetic shield 72a and the second reproduction magnetic shield 72b. The magnetic reproducing element 71 can output a signal corresponding to the magnetization 83 of the magnetic recording layer 81.
As shown in
As shown in
As shown in
As shown in
A direction perpendicular to the medium-opposing surface 30F is taken as a Z-axis direction. One direction perpendicular to the Z-axis direction is taken as an X-axis direction. A direction perpendicular to the Z-axis direction and the X-axis direction is taken as a Y-axis direction.
The Z-axis direction is, for example, the height direction. The X-axis direction is, for example, the down-track direction. The Y-axis direction is, for example, the cross-track direction.
As shown in
As shown in
As shown in
The stacked body 20 includes, for example, the first magnetic layer 21, the second magnetic layer 22, and the third magnetic layer 23. The stacked body 20 includes, for example, the second intermediate layer 42 and the third intermediate layer 43 in addition to the first magnetic layer 21, the second magnetic layer 22, and the third magnetic layer 23. The stacked body 20 may further include the first intermediate layer 41. The stacked body 20 may further include the fourth intermediate layer 44. The first magnetic layer 21 is provided between the magnetic pole 30 and the first shield 31. The second magnetic layer 22 is provided between the first magnetic layer 21 and the first shield 31. The third magnetic layer 23 is provided between the second magnetic layer 22 and the first shield 31.
The first intermediate layer 41 is provided between the magnetic pole 30 and the first magnetic layer 21. The second intermediate layer 42 is provided between the first magnetic layer 21 and the second magnetic layer 22. The third intermediate layer 43 is provided between the second magnetic layer 22 and the third magnetic layer 23. The fourth intermediate layer 44 is provided between the third magnetic layer 23 and the first shield 31. The first to fourth intermediate layers 41 to 44 are nonmagnetic.
The first intermediate layer 41 includes, for example, at least one selected from a first group consisting of Au, Cu, Ag, Al, and Ti. The second intermediate layer 42 includes at least one selected from a second group consisting of Ta, Ir, W, Mo, Cr, Tb, Rh, and Pd. The third intermediate layer 43 includes at least one selected from the first group recited above. The fourth intermediate layer 44 includes at least one selected from the second group recited above.
For example, it is considered that the material of the first group consisting of Au, Cu, Ag, Al, and Ti has the function of efficiently transferring the spin. The material of the first group is, for example, a good spin conductor. It is considered that the material of the second group consisting of Ta, Ir, W, Mo, Cr, Tb, Rh, and Pd has the function of making it difficult to transfer the spin. The material of the second group is, for example, a spin nonconductor.
By such a configuration, an alternating-current magnetic field is generated from the stacked body 20 when the current flows in the stacked body 20.
As shown in
As shown in
As shown in
For example, there are cases where the alternating-current magnetic field generated from the stacked body 20 has a magnetic field having a positive rotation (e.g., counterclockwise), or a magnetic field having a negative rotation (e.g., clockwise). For example, it is considered that the magnetic field having the positive rotation has the action of assisting the recording magnetic field from the magnetic pole 30, and the magnetic field having the negative rotation has the action of weakening the recording magnetic field from the magnetic pole 30. An example of simulation results of the change of the magnetic field having the positive rotation or the negative rotation for the alternating-current magnetic field generated from the stacked body 20 when changing the materials of the intermediate layers recited above will now be described.
In the model of the simulation of the magnetic head 118, the physical property values of Fe60Co40 are used as the physical property values of the first magnetic layer 21. A saturation magnetization Ms of the first magnetic layer 21 is 2.4 T. The first thickness t21 of the first magnetic layer 21 is 9 nm. The physical property values of Ni70Fe30 are used as the physical property values of the second magnetic layer 22. The saturation magnetization Ms of the second magnetic layer 22 is 1 T. The second thickness t22 of the second magnetic layer 22 is 3 nm. The distance of a region g1 between the magnetic pole 30 and the first shield 31 (referring to
In the model of the simulation of the magnetic head 110, the physical property values of Fe60Co40 are used as the physical property values of the first magnetic layer 21. The saturation magnetization Ms of the first magnetic layer 21 is 2.4 T. The first thickness t21 of the first magnetic layer 21 is 6 nm. The physical property values of Fe60Co40 are used as the physical property values of the second magnetic layer 22. The saturation magnetization Ms of the second magnetic layer 22 is 2.4 T. The second thickness t22 of the second magnetic layer 22 is 9 nm. The physical property values of Ni70Fe30 are used as the physical property values of the third magnetic layer 23. The saturation magnetization Ms of the third magnetic layer 23 is 1 T. The third thickness t23 of the third magnetic layer 23 is 3 nm. The thickness t41 of the first intermediate layer 41 is 3 nm. The thickness t42 of the second intermediate layer 42 is 3 nm. The thickness t43 of the third intermediate layer 43 is 3 nm. The thickness t44 of the fourth intermediate layer 44 is 3 nm. The distance of the region g1 between the magnetic pole 30 and the first shield 31 (referring to
In the magnetic head 118 as shown in
Conversely, in the magnetic head 110 as shown in
As shown in
Thus, it was found that compared to the magnetic head 118 of the reference example, good characteristics are obtained in the magnetic head 110 in which the first to third magnetic layers 21 to 23 are provided, the first intermediate layer 41 and the third intermediate layer 43 include the material of the first group recited above, and the second intermediate layer 42 and the fourth intermediate layer 44 include the material of the second group recited above.
As recited above, there are cases where the recording magnetic field is weakened by the rotating magnetic field generated from the stacked body 20. According to the embodiment, the weakening of the recording magnetic field due to the rotating magnetic field is suppressed. According to the embodiment, good MAMR can be performed. According to the embodiment, a magnetic head can be provided in which the recording density can be increased.
As shown in
For example, it is considered that the third magnetic layer 23 functions as a spin injection layer. For example, it is considered that the second magnetic layer 22 functions as an oscillation generation layer. For example, it is considered that the first magnetic layer 21 functions to suppress the magnetic field having the negative rotation.
In these figures, the horizontal axis is a time tm (ns). In these figures, the vertical axis is a magnetization Mx.
As shown in
In the embodiment, for example, the first intermediate layer 41 contacts the first magnetic layer 21. For example, the second intermediate layer 42 contacts the first magnetic layer 21 and the second magnetic layer 22. For example, the third intermediate layer 43 contacts the second magnetic layer 22 and the third magnetic layer 23. For example, the fourth intermediate layer 44 contacts the third magnetic layer 23. For example, the first intermediate layer 41 contacts the magnetic pole 30. For example, the fourth intermediate layer 44 contacts the first shield 31.
In one example, the first thickness t21 of the first magnetic layer 21 is thinner than the second thickness t22 of the second magnetic layer 22. The first thickness t21 is thicker than the third thickness t23 of the third magnetic layer 23.
As described above, the first thickness t21 is, for example, not less than 2.5 nm and not more than 8 nm.
The second thickness t22 is, for example, greater than 5 nm and not more than 15 nm. The second thickness t22 is about 9 nm.
The third thickness t23 is, for example, not less than 1 nm but less than 5 nm. The third thickness t23 is about 3 nm.
The first magnetic layer 21 has a first saturation magnetic flux density. The second magnetic layer 22 has a second saturation magnetic flux density. The third magnetic layer 23 has a third saturation magnetic flux density.
A first product of the first saturation magnetic flux density and the first thickness t21 is smaller than a second product of the second saturation magnetic flux density and the second thickness t22. The first product is larger than a third product of the third saturation magnetic flux density and the third thickness t23. By such a relationship, for example, the magnetostatic coupling between the first magnetic layer 21 and the second magnetic layer 22 is easy. For example, the oscillation of the second magnetic layer 22 is promoted. For example, the generation of the negative rotating magnetic field is suppressed.
The thickness t41 is, for example, not less than 1 nm and not more than 4 nm. The thickness t42 is, for example, not less than 1 nm and not more than 5 nm. The thickness t43 is, for example, not less than 1 nm and not more than 5 nm. The thickness t44 is, for example, not less than 1 nm and not more than 10 nm. Because the thickness t41 is not more than 4 nm, the oscillation of the first magnetic layer 21 is stable. For example, a large parameter PSNR is obtained easily.
In the embodiment, at least one of the first to third magnetic layers 21 to 23 includes at least one selected from the group consisting of Fe, Co, and Ni.
In the embodiment, it is favorable for the thickness of the stacked body 20 to be 25 nm or less. Thereby, for example, a good recording magnetic field gradient is obtained.
An example of simulation results of characteristics of the stacked body 20 when a current is caused to flow in the stacked body 20 will now be described.
In the magnetic head 110 as shown in
In the magnetic head 110 as in the example, there are cases where the electrical resistance Rc changes in three stages. It can be estimated that such a change of the electrical resistance Rc corresponds to the change of the orientation of the magnetization of the magnetic layer. An example of the state of the magnetization of the magnetic head 110 will now be described.
In the magnetic head 110 as shown in
It is considered that such changes of the magnetizations of the magnetic head 110 have a relationship with the change of the electrical resistance Rc illustrated in
In the embodiment, a current flows from the magnetic pole 30 toward the first shield 31 when the information is recorded in the magnetic recording medium 80 by the magnetic head 110. The alternating-current magnetic field (e.g., the high frequency magnetic field) is generated thereby. For example, the alternating-current magnetic field is generated from the stacked body 20 when the recording magnetic field is generated from the magnetic pole 30 and the current flows from the magnetic pole 30 toward the first shield 31. The recording magnetic field is applied to the stacked body 20.
A second embodiment relates to the magnetic recording device 210. The magnetic recording device 210 includes the magnetic head 110, and the magnetic recording medium 80 in which the information is recorded by the magnetic head 110. An example of the magnetic recording device according to the embodiment will now be described. The magnetic recording device may be a magnetic recording and reproducing device. The magnetic head may include a recording portion and a reproducing portion.
The head slider 159 has, for example, an air inflow side 159A and an air outflow side 159B. The magnetic head 110 is disposed at the side surface of the air outflow side 159B of the head slider 159 or the like. Thereby, the magnetic head 110 moves relative to the magnetic recording medium while flying over or contacting the magnetic recording medium.
As shown in
The head slider 159 records and reproduces the information recorded in the recording medium disk 180. The head slider 159 is provided at the tip of a suspension 154 having a thin-film configuration. The magnetic head according to the embodiment is provided at the tip vicinity of the head slider 159.
When the recording medium disk 180 rotates, the downward pressure due to the suspension 154 and the pressure generated in the medium-opposing surface (the ABS) of the head slider 159 are balanced. The distance between the medium-opposing surface of the head slider 159 and the surface of the recording medium disk 180 becomes a prescribed fly height. In the embodiment, the head slider 159 may contact the recording medium disk 180. For example, contact-sliding is applicable.
The suspension 154 is connected to one end of an arm 155 (e.g., an actuator arm). The arm 155 includes, for example, a bobbin part, etc. The bobbin part holds a drive coil. A voice coil motor 156 is provided at the other end of the arm 155. The voice coil motor 156 is one type of linear motor. The voice coil motor 156 includes, for example, the drive coil and a magnetic circuit. The drive coil is wound onto the bobbin part of the arm 155. The magnetic circuit includes a permanent magnet and an opposing yoke. The drive coil is provided between the permanent magnet and the opposing yoke. The suspension 154 has one end and another end. The magnetic head is provided at the one end of the suspension 154. The arm 155 is connected to the other end of the suspension 154.
The arm 155 is held by ball bearings. The ball bearings are provided at two locations above and below a bearing part 157. The arm 155 can rotate and slide due to the voice coil motor 156. The magnetic head is movable to any position of the recording medium disk 180.
As shown in
As shown in
The head slider 159 is provided at the tip of the suspension 154. The magnetic head according to the embodiment is provided at the head slider 159.
The magnetic head assembly (the head gimbal assembly) 158 according to the embodiment includes the magnetic head according to the embodiment, the head slider 159 on which the magnetic head is provided, the suspension 154, and the arm 155. The head slider 159 is provided at one end of the suspension 154. The arm 155 is connected to the other end of the suspension 154.
The suspension 154 includes, for example, lead wires (not illustrated) for recording and reproducing signals. The suspension 154 may include, for example, lead wires (not illustrated) for a heater that adjusts the fly height. The suspension 154 may include, for example, lead wires (not illustrated) for a spin torque oscillator, etc. These lead wires are electrically connected to multiple electrodes provided in the magnetic head.
A signal processor 190 is provided in the magnetic recording device 150. The signal processor 190 records and reproduces the signals to and from the magnetic recording medium by using the magnetic head. For example, the signal processor 190 is electrically connected to the magnetic head by the input/output lines of the signal processor 190 being connected to electrode pads of the head gimbal assembly 158.
The magnetic recording device 150 according to the embodiment includes a magnetic recording medium, the magnetic head according to the embodiment, a movable part, a position controller, and a signal processor. The movable part causes the magnetic recording medium and the magnetic head to separate or causes the magnetic recording medium and the magnetic head to be movable relative to each other in a state of contact. The position controller aligns the magnetic head at a prescribed recording position of the magnetic recording medium. The signal processor records and reproduces the signals to and from the magnetic recording medium by using the magnetic head.
For example, the recording medium disk 180 is used as the magnetic recording medium recited above. The movable part recited above includes, for example, the head slider 159. The position controller recited above includes, for example, the head gimbal assembly 158.
The embodiments may include the following configurations (e.g., technological proposals).
A magnetic head, comprising:
a magnetic pole;
a first shield;
a first magnetic layer provided between the magnetic pole and the first shield;
a second magnetic layer provided between the first magnetic layer and the first shield;
a third magnetic layer provided between the second magnetic layer and the first shield;
a first intermediate layer provided between the magnetic pole and the first magnetic layer, the first intermediate layer including at least one selected from a first group consisting of Au, Cu, Ag, Al, and Ti;
a second intermediate layer provided between the first magnetic layer and the second magnetic layer, the second intermediate layer including at least one selected from a second group consisting of Ta, Ir, W, Mo, Cr, Tb, Rh, and Pd;
a third intermediate layer including at least one selected from the first group and being provided between the second magnetic layer and the third magnetic layer; and
a fourth intermediate layer including at least one selected from the second group and being provided between the third magnetic layer and the first shield.
The magnetic head according to Configuration 1, wherein the first magnetic layer has a first saturation magnetic flux density and a first thickness, the first thickness being along a first direction, the first direction being from the magnetic pole toward the first shield,
the second magnetic layer has a second saturation magnetic flux density and a second thickness, the second thickness being along the first direction, and
a first product of the first saturation magnetic flux density and the first thickness is smaller than a second product of the second saturation magnetic flux density and the second thickness.
The magnetic head according to Configuration 2, wherein
the third magnetic layer has a third saturation magnetic flux density and a third thickness, the third thickness being along the first direction, and
the first product is larger than a third product of the third saturation magnetic flux density and the third thickness.
The magnetic head according to Configuration 1, wherein a first thickness of the first magnetic layer along a first direction is thinner than a second thickness of the second magnetic layer along the first direction, the first direction being from the magnetic pole toward the first shield.
The magnetic head according to Configuration 4, wherein the first thickness is thicker than a third thickness of the third magnetic layer along the first direction.
The magnetic head according to Configuration 1, wherein a first thickness of the first magnetic layer along a first direction is not less than 2.5 nm and not more than 8 nm, the first direction being from the magnetic pole toward the first shield.
The magnetic head according to Configuration 6, wherein a second thickness of the second magnetic layer along the first direction is greater than 5 nm and not more than 15 nm.
The magnetic head according to Configuration 6 or 7, wherein a third thickness of the third magnetic layer along the first direction is not less than 1 nm but less than 5 nm.
The magnetic head according to any one of Configurations 6 to 8, wherein a thickness of the first intermediate layer along the first direction is not less than 1 nm and not more than 4 nm.
The magnetic head according to any one of Configurations 6 to 9, wherein a thickness of the second intermediate layer along the first direction is not less than 1 nm and not more than 5 nm.
The magnetic head according to any one of Configurations 6 to 10, wherein a thickness of the third intermediate layer along the first direction is not less than 1 nm and not more than 5 nm.
The magnetic head according to any one of Configurations 6 to 11, wherein a thickness of the fourth intermediate layer along the first direction is not less than 1 nm and not more than 10 nm.
The magnetic head according to any one of Configurations 6 to 12, wherein a length along the first direction of a stacked body is 25 nm or less, the stacked body including the first magnetic layer, the second intermediate layer, the second magnetic layer, the third intermediate layer, and the third magnetic layer.
The magnetic head according to any one of Configurations 1 to 12, wherein a current density of a current flowing in a stacked body is 2×108 cm2 or more, the stacked body including the first magnetic layer, the second intermediate layer, the second magnetic layer, the third intermediate layer, and the third magnetic layer.
The magnetic head according to any one of Configurations 1 to 14, wherein
the first intermediate layer contacts the first magnetic layer,
the second intermediate layer contacts the first magnetic layer and the second magnetic layer,
the third intermediate layer contacts the second magnetic layer and the third magnetic layer, and
the fourth intermediate layer contacts the third magnetic layer.
The magnetic head according to Configuration 15, wherein the first intermediate layer contacts the magnetic pole.
The magnetic head according to Configuration 16, wherein the fourth intermediate layer contacts the first shield.
The magnetic head according to any one of Configurations 1 to 17, wherein
a stacked body including the first magnetic layer, the second magnetic layer, and the third magnetic layer has a first electrical resistance when a first current having a first orientation is caused to flow in the stacked body, the first orientation being from the first magnetic layer toward the third magnetic layer,
the stacked body has a second electrical resistance when a second current having the first orientation is caused to flow in the stacked body, the second current being larger than the first current,
the stacked body has a third electrical resistance when a third current having the first orientation is caused to flow in the stacked body, the third current being larger than the second current, and
the second electrical resistance is higher than the first electrical resistance and higher than the third electrical resistance.
The magnetic head according to any one of Configurations to 17, wherein an alternating-current magnetic field is generated from a stacked body including the first magnetic layer, the second magnetic layer, and the third magnetic layer when a recording magnetic field is generated from the magnetic pole and a current flows from the magnetic pole toward the first shield.
A magnetic recording device, comprising:
the magnetic head according to any one of Configurations 1 to 19; and
a magnetic recording medium, information being recorded in the magnetic recording medium by the magnetic head.
According to the embodiments, a magnetic head and a magnetic recording device can be provided in which the recording density 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 heads such as magnetic poles, first shields, second shields, stacked bodies, magnetic layers, intermediate layers, wirings, 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 heads, and magnetic recording devices practicable by an appropriate design modification by one skilled in the art based on the magnetic heads, and the magnetic recording 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 |
---|---|---|---|
JP2019-163030 | Sep 2019 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
8879205 | Shiimoto | Nov 2014 | B2 |
9064508 | Shiimoto | Jun 2015 | B1 |
9087532 | Shimizu et al. | Jul 2015 | B2 |
9099107 | Igarashi | Aug 2015 | B1 |
9805746 | Okamura | Oct 2017 | B1 |
10090007 | Zhu | Oct 2018 | B2 |
10839833 | Freitag | Nov 2020 | B1 |
10937450 | Kawasaki | Mar 2021 | B1 |
20080019040 | Zhu | Jan 2008 | A1 |
20080268291 | Akiyama | Oct 2008 | A1 |
20100027158 | Takagishi et al. | Feb 2010 | A1 |
20110096443 | Zhang | Apr 2011 | A1 |
20120126905 | Zhang | May 2012 | A1 |
20130271866 | Sato | Oct 2013 | A1 |
20140036387 | Sato | Feb 2014 | A1 |
20140377589 | Freitag | Dec 2014 | A1 |
20180268848 | Narita | Sep 2018 | A1 |
20190086377 | Ikehashi et al. | Mar 2019 | A1 |
20200294537 | Nagasawa | Sep 2020 | A1 |
Number | Date | Country |
---|---|---|
2010-40060 | Feb 2010 | JP |
2019-56607 | Apr 2019 | JP |
Entry |
---|
Zhu, J., “Dual Side Spin Transfer Spin Torque Oscillator for Microwave Assisted Magnetic Recording,” Joint MMM-Intermag Conference Abstracts, p. 9, AB-11 (2016). |
Number | Date | Country | |
---|---|---|---|
20210074320 A1 | Mar 2021 | US |