Magnetic recording device

Abstract

To provide a magnetic recording device that enables improved recording density. [Solution] According to the embodiment, the magnetic recording device includes a magnetic head and a control unit. The magnetic head includes first and second magnetic poles, a magnetic element, and a coil. The control unit is configured to perform a first operation. In the first operation, the control unit is configured to supply a recording element current to the magnetic element and a recording coil current to the coil. The absolute value of the recording coil current is greater than or equal to the coil current value. The recording element current is less than or equal to the first current value.

Description

Technical Field

[0001] Embodiments of the present invention relate to a magnetic recording device.

Background Art

[0002] Information is recorded on a magnetic recording medium such as an HDD (Hard Disk Drive) using a magnetic head. In a magnetic recording device, an improvement in recording density is desired.

Prior Art Documents

Patent Documents

[0003] [[ID=2t]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Embodiments of the present invention provide a magnetic recording device capable of improving recording density.

Means for Solving the Problems

[0005] According to embodiments of the present invention, a magnetic recording device includes a magnetic head and a control unit. The magnetic head includes a first magnetic pole, a second magnetic pole, a magnetic element provided between the first magnetic pole and the second magnetic pole, a coil, a first terminal, and a second terminal. The first terminal is electrically connected to a part of the magnetic element. The second terminal is electrically connected to another part of the magnetic element. The magnetic element includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic pole, a first non-magnetic layer provided between the first magnetic layer and the second magnetic layer, a second non-magnetic layer provided between the second magnetic layer and the second magnetic pole, and a third non-magnetic layer provided between the first magnetic pole and the first magnetic layer. When a first coil current of a first frequency is supplied to the coil and a first current is supplied between the first terminal and the second terminal, a first signal having a first signal intensity of a first component of the first frequency is generated between the first terminal and the second terminal. When the first coil current is supplied to the coil and a second current is supplied between the first terminal and the second terminal, a second signal having a second signal intensity of a second component of the first frequency is generated between the first terminal and the second terminal. The absolute value of the first coil current is greater than or equal to the coil current value. The first current has a first direction from the first magnetic layer to the second magnetic layer. The second current has a second direction from the second magnetic layer to the first magnetic layer. The second absolute value of the second current is the same as the first absolute value of the first current. When the first absolute value is changed, the change in the absolute value of the difference between the time integration of the first signal intensity and the time integration of the second signal intensity includes a first peak and a second peak. The first current value of the first absolute value corresponds to the first peak. The second current value of the first absolute value corresponds to the second peak. The first current value is greater than the second current value. The control unit is configured to perform the first operation. In the first operation, the control unit is configured to supply a recording coil current to the coil while simultaneously supplying a recording element current to the magnetic element. The absolute value of the recording coil current is greater than or equal to the coil current value. The recording element current is less than or equal to the first current value. [Brief explanation of the drawing]

[0006] [Figure 1] Figure 1 is a schematic cross-sectional view illustrating a magnetic recording device according to the first embodiment. [Figure 2] Figures 2(a) and 2(b) are schematic diagrams illustrating a part of the magnetic recording device according to the first embodiment. [Figure 3] Figure 3 is a schematic diagram illustrating the operation of a magnetic recording device according to the first embodiment. [Figure 4] Figures 4(a) to 4(c) are graphs illustrating the characteristics of the magnetic recording device according to the first embodiment. [Figure 5] Figures 5(a) to 5(c) are graphs illustrating the characteristics of a magnetic recording device according to the first embodiment. [Figure 6] Figure 6 is a schematic diagram illustrating another operation of the magnetic recording device according to the first embodiment. [Figure 7] Figures 7(a) to 7(c) are graphs illustrating the characteristics of a magnetic recording device according to the first embodiment. [Figure 8] Figures 8(a) and 8(b) are schematic plan views illustrating a magnetic head according to the first embodiment. [Figure 9] Figure 9 is a schematic cross-sectional view illustrating a magnetic head according to an embodiment. [Figure 10] Figure 10 is a schematic perspective view illustrating a magnetic recording device according to an embodiment. [Figure 11] Figure 11 is a schematic perspective view illustrating a part of a magnetic recording apparatus according to an embodiment. [Figure 12] Figure 12 is a schematic perspective view illustrating a magnetic recording device according to an embodiment. [Figure 13] Figures 13(a) and 13(b) are schematic perspective views illustrating a part of a magnetic recording apparatus according to an embodiment. [Modes for carrying out the invention]

[0007] The embodiments of the present invention will be described below with reference to the drawings. Drawings are schematic or conceptual, and the relationships between the thickness and width of each part, as well as the ratios of the sizes of different parts, are not necessarily identical to those of reality. Even when representing the same part, the dimensions and ratios may be depicted differently in different drawings. In this specification and in each figure, elements similar to those described above are denoted by the same reference numerals with respect to previously shown figures, and detailed explanations are omitted as appropriate.

[0008] (First Embodiment) Figure 1 is a schematic cross-sectional view illustrating a magnetic recording device according to the first embodiment. Figures 2(a) and 2(b) are schematic diagrams illustrating a part of the magnetic recording device according to the first embodiment. Figure 2(a) is a cross-sectional view. Figure 2(b) is a plan view taken from arrow AR1 in Figure 2(a). Figure 3 is a schematic diagram illustrating the operation of a magnetic recording device according to the first embodiment. Figures 4(a) to 4(c) are graphs illustrating the characteristics of the magnetic recording device according to the first embodiment. Figures 5(a) to 5(c) are graphs illustrating the characteristics of a magnetic recording device according to the first embodiment.

[0009] As shown in Figure 1, the magnetic recording device 210 according to this embodiment includes a magnetic head 110 and a control unit 10D. The magnetic recording device 210 may also include a magnetic recording medium 80. At least a recording operation is performed in the magnetic recording device 210. In the recording operation, information is recorded on the magnetic recording medium 80 using the magnetic head 110.

[0010] The magnetic head 110 includes a recording unit 60. As will be described later, the magnetic head 110 may also include a playback unit. The recording unit 60 includes a first magnetic pole 31, a second magnetic pole 32, and a magnetic element 20. The magnetic element 20 is provided between the first magnetic pole 31 and the second magnetic pole 32.

[0011] For example, the first magnetic pole 31 and the second magnetic pole 32 form a magnetic circuit. The first magnetic pole 31 is, for example, a main magnetic pole. The second magnetic pole 32 is, for example, a trailing shield. It is also possible that the first magnetic pole 31 is a trailing shield and the second magnetic pole 32 is a main magnetic pole.

[0012] The direction from the magnetic recording medium 80 to the magnetic head 110 is defined as the Z-axis direction. One direction perpendicular to the Z-axis direction is defined as the X-axis direction. The direction perpendicular to both the Z-axis direction and the X-axis direction is defined as the Y-axis direction. The Z-axis direction corresponds to, for example, the height direction. The X-axis direction corresponds to, for example, the down-track direction. The Y-axis direction corresponds to, for example, the cross-track direction. Along the down-track direction, the magnetic recording medium 80 and the magnetic head 110 move relatively to each other. A magnetic field (recording magnetic field) generated from the magnetic head 110 is applied to a target position on the magnetic recording medium 80. The magnetization of the target position on the magnetic recording medium 80 is controlled in a direction corresponding to the recording magnetic field. Thereby, information is recorded on the magnetic recording medium 80.

[0013] The direction from the first magnetic pole 31 to the second magnetic pole 32 is defined as the first direction D1. The first direction D1 substantially follows the X-axis direction. In an embodiment, the first direction D1 may be inclined at a small angle with respect to the X-axis direction.

[0014] As shown in FIG. 1, the first magnetic pole 31 includes a medium facing surface 30F. The medium facing surface 30F is, for example, an ABS (Air Bearing Surface). The medium facing surface 30F faces, for example, the magnetic recording medium 80. The medium facing surface 30F is along, for example, the X-Y plane.

[0015] As shown in Figure 1, the magnetic head 110 further includes a coil 30c. In this example, a portion of the coil 30c lies between the first magnetic pole 31 and the second magnetic pole 32. In this example, a shield 33 is provided. In the X-axis direction, the first magnetic pole 31 is located between the shield 33 and the second magnetic pole 32. Another portion of the coil 30c lies between the shield 33 and the first magnetic pole 31. An insulating portion 30i is provided between these multiple elements. The shield 33 is, for example, a reading shield. The magnetic head 110 may also include a side shield (not shown).

[0016] As shown in Figure 1, the control unit 10D may include a recording circuit 30D and an element electrical circuit 20D. A recording current (recording coil current Iw0) is supplied from the recording circuit 30D to the coil 30c. A recording magnetic field corresponding to the recording coil current Iw0 is applied to the magnetic recording medium 80 from at least one of the first magnetic pole 31 and the second magnetic pole 32.

[0017] As shown in Figure 1, the element electrical circuit 20D is electrically connected to the magnetic element 20. In this example, the magnetic element 20 is electrically connected to a first magnetic pole 31 and a second magnetic pole 32. The magnetic head 110 includes, for example, a first terminal T1 and a second terminal T2. The first terminal T1 is electrically connected to a portion of the magnetic element 20. The second terminal T2 is electrically connected to another portion of the magnetic element 20. For example, the first terminal T1 is electrically connected to the magnetic element 20 via a first wiring W1 and the first magnetic pole 31. For example, the second terminal T2 is electrically connected to the magnetic element 20 via a second wiring W2 and the second magnetic pole 32. From the element electrical circuit 20D, for example, a recording element current Idw is supplied to the magnetic element 20. The recording element current Idw is, for example, a DC current.

[0018] As shown in Figures 2(a) and 2(b), the magnetic element 20 includes a first magnetic layer 21, a second magnetic layer 22, a first non-magnetic layer 41, a second non-magnetic layer 42, and a third non-magnetic layer 43. In Figures 2(a) and 2(b), the insulating portion 30i is omitted.

[0019] The second magnetic layer 22 is provided between the first magnetic layer 21 and the second magnetic pole 32. The first non-magnetic layer 41 is provided between the first magnetic layer 21 and the second magnetic layer 22. The second non-magnetic layer 42 is provided between the second magnetic layer 22 and the second magnetic pole 32. The third non-magnetic layer 43 is provided between the first magnetic pole 31 and the first magnetic layer 21.

[0020] For example, the third non-magnetic layer 43 may be in contact with the first magnetic pole 31 and the first magnetic layer 21. The first non-magnetic layer 41 may be in contact with the first magnetic layer 21 and the second magnetic layer 22. The second non-magnetic layer 42 may be in contact with the second magnetic layer 22 and the second magnetic pole 32.

[0021] As shown in Figure 2(b), a recording element current Idw is supplied to such a magnetic element 20. The recording element current Idw is supplied, for example, from the element electrical circuit 20D described above. As shown in Figure 2(b), the recording element current Idw has a direction from the first magnetic layer 21 to the second magnetic layer 22. As shown in Figure 2(b), the electron flow je associated with the recording element current Idw has a direction from the second magnetic layer 22 to the first magnetic layer 21.

[0022] For example, when an external magnetic field is applied to the magnetic element 20, a recording element current Idw exceeding a threshold flows through the magnetic element 20. This causes the magnetization of the magnetic layer contained in the magnetic element 20 to oscillate. The magnetic element 20 functions, for example, as an STO (Spin-Torque Oscillator). Along with the oscillation, an alternating magnetic field (for example, a high-frequency magnetic field) is generated from the magnetic element 20. The alternating magnetic field generated by the magnetic element 20 is applied to the magnetic recording medium 80, assisting in writing to the magnetic recording medium 80. For example, MAMR (Microwave Assisted Magnetic Recording) can be implemented. The recording magnetic field based on the above-mentioned recording coil current Iw0 may function as the magnetic field applied to the magnetic element 20.

[0023] The following describes examples of the characteristics of such magnetic element 20. Figure 3 illustrates a test first coil current Ic1 supplied to coil 30c. The horizontal axis in Figure 3 represents time tm, and the vertical axis represents the first coil current Ic1. The first coil current Ic1 varies with a first frequency f1. The first frequency f1 corresponds to the reciprocal of the period Tf1 of the first coil current Ic1. In Figure 3, the first coil current Ic1 varies between "-Ic" and "+Ic". For example, the absolute value of the first coil current Ic1 corresponds to half the amplitude when the first coil current Ic1 is a square wave.

[0024] It was found that when a current is supplied between the first terminal T1 and the second terminal T2 while a test current Ic1 is supplied to the first coil, a specific change occurs between the first terminal T1 and the second terminal T2.

[0025] Figure 4(a) corresponds to the case where the absolute value of the first coil current Ic1 is 0. Figure 4(b) corresponds to the case where the absolute value of the first coil current Ic1 is greater than 0 and less than the coil current value Icth. The coil current value Icth is, for example, a threshold current and depends on the configuration of the magnetic element 20, etc. Figure 4(c) corresponds to the case where the absolute value of the first coil current Ic1 is greater than or equal to the coil current value Icth.

[0026] Figures 4(a) to 4(c) illustrate the first signal strength SS1 of the first signal Sg1 generated in the first current Id1 when the first current Id1 is supplied to the magnetic element 20. Figures 4(a) to 4(c) also illustrate the second signal strength SS2 of the second signal Sg2 generated in the second current Id2 when the second current Id2 is supplied to the magnetic element 20. The first current Id1 has a first direction from the first magnetic layer 21 to the second magnetic layer 22 (see Figure 2(b)). The second current Id2 has a second direction from the second magnetic layer 22 to the first magnetic layer 21.

[0027] When a first coil current Ic1 with a first frequency f1 is supplied to coil 30c, and a first current Id1 is supplied between the first terminal T1 and the second terminal T2 (i.e., to the magnetic element 20), a first signal Sg1 having a first signal intensity SS1 of the first component of the first frequency f1 is generated between the first terminal T1 and the second terminal T2. The first signal Sg1 may be, for example, a voltage signal or a power signal.

[0028] When a first coil current Ic1 with a first frequency f1 is supplied to coil 30c, and a second current Id2 is supplied between the first terminal T1 and the second terminal T2 (i.e., to the magnetic element 20), a second signal Sg2 having a second signal strength SS2 of the second component of the first frequency f1 is generated between the first terminal T1 and the second terminal T2 (i.e., to the magnetic element 20). The second signal Sg2 may be, for example, a voltage signal or a power signal.

[0029] Figures 4(a) to 4(c) illustrate the change in the first signal strength SS1 of the first signal Sg1 when the first absolute value |Id1| of the first current Id1 is changed, with solid lines. Figures 4(a) to 4(c) illustrate the change in the second signal strength SS2 of the second signal Sg2 when the second absolute value |Id2| of the second current Id2 is changed, with dashed lines. In Figures 4(a) and 4(b), the dashed line (second signal Sg2) substantially overlaps with the solid line (first signal Sg1). In Figure 4(c), the dashed line (second signal Sg2) does not overlap with the solid line (first signal Sg1) in most parts.

[0030] As shown in Figure 4(a), when the magnitude (amplitude) of the first coil current Ic1 is 0, the first signal intensity SS1 of the first signal Sg1 increases gradually with increasing first absolute value |Id1| of the first current Id1. The second signal intensity SS2 of the second signal Sg2 increases gradually with increasing second absolute value |Id2| of the second current Id2. These phenomena are thought to be due to an increase in thermal fluctuations in the magnetic element 20 as the first absolute value |Id1| of the first current Id1 and the second absolute value |Id2| of the second current Id2 increase. At this time, even if the direction of the current flowing through the magnetic element 20 is reversed, the signal intensity does not substantially change.

[0031] As shown in Figure 4(b), when the magnitude of the first coil current Ic1 is less than the coil current value Icth (threshold), the first signal intensity SS1 of the first signal Sg1 and the second signal intensity SS2 of the second signal Sg2 increase gradually with increasing first absolute value |Id1| of the first current Id1 and second absolute value |Id2| of the second current Id2.

[0032] Figure 4(b) illustrates the characteristics of a third signal Sg3 having a third signal intensity SS3 that is not the first frequency f1. In this example, the third signal Sg3 is a component with a frequency 1.1 times that of the first frequency f1. As shown in Figure 4(b), the intensity of the first signal Sg1, which is the first component of the first current Id1 at the first frequency f1, is higher than the intensity of the third signal Sg3. The intensity of the second signal Sg2, which is the second component of the second current Id2 at the first frequency f1, is higher than the intensity of the third signal Sg3.

[0033] The characteristics in Figure 4(b) show that the first current Id1 and the second current Id2 supplied to the element are affected by the first coil current Ic1. In Figure 4(b), the effect of the first coil current Ic1 is considered to be an electromagnetic effect caused by the first coil current Ic1 which changes at the first frequency f1.

[0034] As shown in Figure 4(c), when the magnitude of the first coil current Ic1 is greater than or equal to the coil current value Icth (threshold), the first signal intensity SS1 of the first signal Sg1 is different from the second signal intensity SS2 of the second signal Sg2. This phenomenon is thought to be caused by a change in the magnetization state of the magnetic layer contained in the magnetic element 20 due to the influence of the magnetic field above the threshold caused by the first coil current Ic1 and the current flowing through the magnetic element 20.

[0035] As shown in Figure 4(c), when the first absolute value |Id1| of the first current Id1 and the second absolute value |Id2| of the second current Id2 are small, the first signal intensity SS1 of the first signal Sg1 substantially matches the second signal intensity SS2 of the second signal Sg2.

[0036] When the first absolute value |Id1| of the first current Id1 and the second absolute value |Id2| of the second current Id2 are greater than or equal to the second current value Iv2, the first signal intensity SS1 of the first signal Sg1 differs from the second signal intensity SS2 of the second signal Sg2.

[0037] The following explains the difference ΔS1 between the time integration of the first signal intensity SS1 of the first component of the first signal Sg1 at the first frequency f1, and the time integration of the second signal intensity SS2 of the second component of the second signal Sg2 at the first frequency f1.

[0038] Figures 5(a) to 5(c) illustrate the difference ΔS1 when the first absolute value |Id1| of the first current Id1 is changed. The difference ΔS1 is the difference between the time integration of the first signal intensity SS1 of the first component of the first signal Sg1 at the first frequency f1 and the time integration of the second signal intensity SS2 of the second component of the second signal Sg2 at the first frequency f1.

[0039] As shown in Figure 5(a), when the magnitude (amplitude) of the first coil current Ic1 is 0, the difference ΔS1 is practically 0.

[0040] As shown in Figure 5(b), even when the magnitude of the first coil current Ic1 is less than the coil current value Icth (threshold), the difference ΔS1 is effectively 0.

[0041] Figure 5(c) corresponds to the case where the magnitude of the first coil current Ic1 is greater than or equal to the coil current value Icth (threshold). When the first absolute value |Id1| of the first current Id1 changes, the change in the difference ΔS1 includes peaks (e.g., the first peak pk1 and the second peak pk2).

[0042] Thus, when the first absolute value |Id1| of the first current Id1 is changed, the change in the absolute value of the difference ΔS1 between the time integration of the first signal intensity SS1 and the time integration of the second signal intensity SS2 includes the first peak pk1 and the second peak pk2. The first absolute value |Id1| includes the first current value Iv1 corresponding to the first peak pk1 and the second current value Iv2 corresponding to the second peak pk2. The first current value Iv1 of the first absolute value |Id1| corresponds to the first peak pk1. The second current value Iv2 of the first absolute value |Id1| corresponds to the second peak pk2. The first current value Iv1 is greater than the second current value Iv2.

[0043] For example, when the magnitude of the first coil current Ic1 is greater than or equal to the coil current value Icth, and the first absolute value |Id1| is greater than or equal to the second current value Iv2, the magnetic element 20 is affected by the first coil current Ic1 and the first current Id1. For example, the magnetic field based on the first coil current Ic1 and the first current Id1 supplied to the magnetic element 20 effectively act on the magnetic element 20. For example, an alternating magnetic field is effectively generated from the magnetic element 20. For example, magnetization oscillation can be efficiently obtained.

[0044] If the magnitude of the first coil current Ic1 is greater than or equal to the coil current value Icth, and the first absolute value |Id1| exceeds the first current value Iv1, then the magnetic element 20 is considered to be excessively affected by the first current Id1. For example, the efficiency of generating an alternating magnetic field from the magnetic element 20 decreases.

[0045] Based on the characteristics illustrated in Figure 4(c) or Figure 5(c), an appropriate element current (recording element current Idw) may be set during the recording operation.

[0046] For example, the control unit 10D may be configured to perform a first operation. The first operation corresponds to a recording operation. In the first operation, the control unit 10D is configured to supply a recording element current Idw to the magnetic element 20 while simultaneously supplying a recording coil current Iw0 to the coil 30c. The absolute value of the recording coil current Iw0 is greater than or equal to the coil current value Icth (threshold). The recording element current Idw is less than or equal to a first current value Iv1. This suppresses, for example, a decrease in the efficiency of generating an AC magnetic field from the magnetic element 20. This enables efficient recording. This makes it possible to provide a magnetic recording device that can improve recording density.

[0047] In this embodiment, the element current Idw during recording may be greater than or equal to the second current value Iv2. The magnetic field based on the first coil current Ic1 and the first current Id1 supplied to the magnetic element 20 act more effectively on the magnetic element 20. For example, an alternating magnetic field is more effectively generated from the magnetic element 20.

[0048] As shown in Figure 5(c), the first current value Iv1 is substantially three times the second current value Iv2. In this embodiment, the first current value Iv1 may be between 2.5 and 3.5 times the second current value Iv2.

[0049] The first height of the first peak pk1 may be higher than the second height of the second peak pk2. The first peak pk1 may be more distinct than the second peak pk2.

[0050] The changes in the first peak pk1 and the second peak pk2 with respect to the increase or decrease in the absolute value of the first current Id1 may be asymmetrical. In this example, the steepness of the change in the first peak pk1 when the absolute value of the first current Id1 changes within the range less than the first current value Iv1 is greater than the steepness of the change in the first peak pk1 when the absolute value of the first current Id1 changes within the range greater than the first current value Iv1. The steepness of the change in the second peak pk2 when the absolute value of the first current Id1 changes within the range less than the second current value Iv2 is greater than the steepness of the change in the second peak pk2 when the absolute value of the first current Id1 changes within the range greater than the second current value Iv2.

[0051] An example of the differential resistance characteristics of the magnetic element 20 described above will be explained. Figure 6 is a schematic diagram illustrating another operation of the magnetic recording device according to the first embodiment. As shown in Figure 6, a DC second coil current Ic2 is supplied to the coil 30c. The absolute value of the second coil current Ic2 is greater than or equal to the coil current value Icth (threshold). In this state, when the third current supplied to the magnetic element 20 is changed, the electrical resistance (differential resistance) of the magnetic element 20 may change in accordance with the third current. The third current has a first direction from the first magnetic layer 21 to the second magnetic layer 22 (see Figure 2(b)).

[0052] Figures 7(a) to 7(c) are graphs illustrating the characteristics of a magnetic recording device according to the first embodiment. The horizontal axis of these figures represents the third absolute value |Id3| of the third current Id3. The vertical axis of these figures represents the differential resistance Rd1 of the magnetic element 20. Figure 7(a) corresponds to the case where the magnitude (amplitude) of the second coil current Ic2 is 0. Figure 7(b) corresponds to the case where the magnitude of the second coil current Ic2 is greater than 0 and less than the coil current value Icth (threshold). Figure 7(c) corresponds to the case where the magnitude of the second coil current Ic2 is greater than or equal to the coil current value Icth (threshold).

[0053] As shown in Figure 7(c), when the magnitude (third absolute value |Id3|) of the third current Id3 supplied between the first terminal T1 and the second terminal T2 (i.e., to the magnetic element 20) changes while a DC second coil current Ic2 is supplied to the coil 30c, the change in the differential resistance Rd1 of the magnetic element 20 with respect to the change in the magnitude of the third current Id3 includes a valley Vb1. The differential resistance Rd1 may include a gradually rising background. This rise is thought to be due to the heat generated by the flow of the third current Id3. The magnitude (third absolute value |Id3|) of the third current Id3 corresponding to the valley Vb1 is the first valley current value Iu1.

[0054] The valley Vb1 is thought to correspond, for example, to a change in the magnetization state of each of the multiple magnetic layers contained in the magnetic element 20. For example, when a current less than or equal to the first valley current value Iu1 is supplied to the magnetic element 20, the magnetization of each of the multiple magnetic layers contained in the magnetic element 20 is thought to oscillate stably. For example, when a current exceeding the first valley current value Iu1 is supplied to the magnetic element 20, the oscillation state of each of the multiple magnetic layers contained in the magnetic element 20 is thought to deteriorate.

[0055] In this embodiment, the element current Idw during recording is preferably less than or equal to the first valley current value Iu1. This allows for, for example, efficient oscillation.

[0056] The first valley current value Iu1 may substantially coincide with the first current value Iv1. For example, 1 / 3 of the first valley current value Iu1 may substantially coincide with the second current value Iv2. For example, the first valley current value Iu1 may be 2.5 times or more and 3.5 times or less of the second current value Iv2.

[0057] In this embodiment, at least one of the first peak pk1 and the second peak pk2 described above may not be sufficiently clear. In this case, the element current Idw during recording may be determined based on the first valley current value Iu1.

[0058] For example, when a DC second coil current Ic2 is supplied to coil 30c and the magnitude of a third current Id3 supplied between the first terminal T1 and the second terminal T2 (i.e., to the magnetic element 20) changes, the change in the differential resistance Rd1 of the magnetic element 20 with respect to the change in the magnitude of the third current Id3 includes a valley Vb1 in the third current Id3 with a first valley current value Iu1. The absolute value of the second coil current Ic2 is greater than or equal to the coil current value Icth. The third current Id3 has a first direction from the first magnetic layer 21 to the second magnetic layer 22. The control unit 10D is configured to perform a first operation. In the first operation, the control unit 10D is configured to supply a recording element current Idw to the magnetic element 20 and a recording coil current Iw0 to coil 30c. The absolute value of the recording coil current Iw0 is greater than or equal to the coil current value Icth. The recording element current Idw may be less than or equal to the first valley current value Iu1. For example, efficient oscillation can be obtained. The element current Idw during recording can be 0.3 times or more the first valley current value Iu1.

[0059] In the embodiment, at least one of the first non-magnetic layer 41, the second non-magnetic layer 42, and the third non-magnetic layer 43 contains a third element. The third element includes, for example, at least one selected from the group consisting of Cu, Au, Cr, V, Al, and Ag. In a non-magnetic layer containing such a material, for example, high spin transmittance can be obtained. For example, high oscillation intensity can be obtained.

[0060] At least one of the second non-magnetic layer 42 and the third non-magnetic layer 43 may contain a fourth element. The fourth element includes, for example, at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt, and W. In a non-magnetic layer containing such a material, for example, a low spin transmittance can be obtained. For example, stable oscillation can be easily obtained. At least one of the second non-magnetic layer 42 and the third non-magnetic layer 43 may contain the above-mentioned third and fourth elements.

[0061] In this embodiment, the first magnetic layer 21 contains a first element. The first element contains at least one of Fe, Co, and Ni.

[0062] The second magnetic layer 22 contains the first element and the second element. The second element includes at least one selected from the group consisting of Cr, V, Mn, Ti, and Sc. The first magnetic layer 21 does not contain the second element, or the concentration of the second element in the first magnetic layer 21 is lower than the concentration of the second element in the second magnetic layer 22.

[0063] For example, the concentration of the above-mentioned second element in the second magnetic layer 22 is between 10 atomic percent and 80 atomic percent. The second magnetic layer 22 containing such a material has, for example, negative spin polarization. On the other hand, for example, the first magnetic layer 21 has positive spin polarization.

[0064] With the first magnetic layer 21 and the second magnetic layer 22, a stable alternating magnetic field of high intensity can be obtained.

[0065] In the magnetic head 110, the first magnetic layer 21 and the second magnetic layer 22 function as, for example, oscillation layers. For example, a negative transmitted spin torque from the second magnetic layer 22 acts on the first magnetic layer 21. For example, a spin torque reflected by the first magnetic layer 21 acts on the second magnetic layer 22. For example, the magnetization of the first magnetic layer 21 and the magnetization of the second magnetic layer 22 rotate while interacting with each other.

[0066] As shown in Figure 2(b), the thickness of the first magnetic layer 21 along the first direction (from the first magnetic pole 31 to the second magnetic pole 32) is defined as the first thickness t1. The thickness of the second magnetic layer 22 along the first direction is defined as the second thickness t2. In this embodiment, for example, the first thickness t1 may be the same as the second thickness t2. This makes it easier to obtain oscillation, as will be described later.

[0067] The thickness of the first non-magnetic layer 41 along the first direction is defined as thickness t41. The thickness of the second non-magnetic layer 42 along the first direction is defined as thickness t42. The thickness of the third non-magnetic layer 43 along the first direction is defined as thickness t43. These thicknesses are, for example, between 0.5 nm and 6 nm. When these thicknesses are 0.5 nm or more, stable oscillation becomes easier. When these thicknesses are 6 nm or less, for example, the spin transmittance tends to be higher. For example, high oscillation intensity is easier to obtain.

[0068] Let the thickness ratio R1 be the ratio of the first thickness t1 to the second thickness t2 (i.e., t1 / t2). When the thickness ratio R1 is close to 1, a high oscillation intensity can be obtained. For example, stable oscillation can be obtained when the thickness ratio R1 is between 0.25 and 4. The thickness ratio R1 can also be 0.33 or higher, and an even higher oscillation intensity can be obtained. The thickness ratio R1 can also be 3 or lower, and an even higher oscillation intensity can be obtained.

[0069] In the embodiment, the first thickness t1 is preferably 0.25 to 4 times the second thickness t2. This allows for high oscillation intensity and stable oscillation. The first thickness t1 may also be 0.33 to 3 times the second thickness t2. This allows for even higher oscillation intensity and more stable oscillation. According to the embodiment, stable MAMR can be implemented, and a magnetic head capable of improving recording density can be provided.

[0070] The first thickness t1 is preferably 5 nm or more. The first thickness t1 may be, for example, 20 nm or less. For example, the distance between the first magnetic pole 31 and the second magnetic pole 32 (e.g., the recording gap) can be shortened. For example, a high recording density can be easily obtained. The second thickness t2 is preferably 5 nm or more. The second thickness t2 may be 20 nm or less. For example, the recording gap can be shortened. For example, a high recording density can be easily obtained. The sum ts of the first thickness t1 and the second thickness t2 is preferably 15 nm or more. This allows for high oscillation intensity. The sum ts may be 40 nm or less. For example, the recording gap can be shortened. For example, a high recording density can be easily obtained.

[0071] Figures 8(a) and 8(b) are schematic plan views illustrating a magnetic head according to the first embodiment. As shown in Figure 8(a), the magnetic head 111 according to the embodiment includes a first magnetic pole 31, a second magnetic pole 32, and a magnetic element 20. In the magnetic head 111, the magnetic element 20 also includes a first magnetic layer 21, a second magnetic layer 22, a first non-magnetic layer 41, a second non-magnetic layer 42, and a third non-magnetic layer 43. In the magnetic head 111, at least one of the first magnetic layer 21 and the second magnetic layer 22 includes multiple regions. Other configurations in the magnetic head 111 may be the same as those in the magnetic head 110.

[0072] For example, the first magnetic layer 21 includes a first magnetic region 21a and a second magnetic region 21b. The second magnetic region 21b is located between the first magnetic region 21a and the first non-magnetic layer 41. For example, the saturation magnetization of the first magnetic region 21a is greater than the saturation magnetization of the second magnetic region 21b. This makes it easier to obtain stable oscillation, for example.

[0073] For example, the saturation magnetization of the first magnetic region 21a is 1.2 times or more the saturation magnetization of the second magnetic region 21b. This makes it easier to obtain stable oscillation. The saturation magnetization of the first magnetic region 21a may be 3 times or less the saturation magnetization of the second magnetic region 21b. This also makes it easier to obtain stable oscillation.

[0074] For example, the Fe concentration in the first magnetic region 21a is higher than the Fe concentration in the second magnetic region 21b. For example, the saturation magnetization of the first magnetic region 21a tends to be greater than the saturation magnetization of the second magnetic region 21b. For example, the Ni concentration in the first magnetic region 21a is lower than the Ni concentration in the second magnetic region 21b. As a result, for example, the saturation magnetization of the first magnetic region 21a tends to be greater than the saturation magnetization of the second magnetic region 21b. The boundary between the first magnetic region 21a and the second magnetic region 21b may be clear or unclear.

[0075] For example, the second magnetic layer 22 includes a third magnetic region 22c and a fourth magnetic region 22d. The fourth magnetic region 22d is located between the third magnetic region 22c and the first non-magnetic layer 41. For example, the saturation magnetization of the third magnetic region 22c is greater than the saturation magnetization of the fourth magnetic region 22d. This makes it easier to obtain stable oscillation, for example.

[0076] For example, the saturation magnetization of the third magnetic region 22c is 1.2 times or more the saturation magnetization of the fourth magnetic region 22d. This makes it easier to obtain stable oscillation. The saturation magnetization of the third magnetic region 22c may be 3 times or less the saturation magnetization of the fourth magnetic region 22d. This also makes it easier to obtain stable oscillation.

[0077] For example, the Fe concentration in the third magnetic region 22c is higher than the Fe concentration in the fourth magnetic region 22d. As a result, for example, the saturation magnetization of the third magnetic region 22c tends to be higher than the saturation magnetization of the fourth magnetic region 22d. For example, the concentration of the second element in the third magnetic region 22c is lower than the concentration of the second element in the fourth magnetic region 22d. As a result, for example, the saturation magnetization of the third magnetic region 22c tends to be higher than the saturation magnetization of the fourth magnetic region 22d. The boundary between the third magnetic region 22c and the fourth magnetic region 22d may be clear or unclear.

[0078] As shown in Figure 8(b), the magnetic head 112 according to the embodiment includes a first magnetic pole 31, a second magnetic pole 32, and a magnetic element 20. In the magnetic head 112, the magnetic element 20 includes a first magnetic layer 21, a second magnetic layer 22, a first non-magnetic layer 41, a second non-magnetic layer 42, and a third non-magnetic layer 43, in addition to a third magnetic layer 23. Other configurations in the magnetic head 112 may be the same as those in the magnetic head 110 or magnetic head 111.

[0079] The third magnetic layer 23 is provided between the second magnetic layer 22 and the second non-magnetic layer 42. The third magnetic layer 23 contains a first element, which includes at least one of Fe, Co, and Ni. The third magnetic layer 23 does not contain a second element, or the concentration of the second element in the third magnetic layer 23 is lower than the concentration of the second element in the second magnetic layer 22. As already described, the second element includes at least one selected from the group consisting of Cr, V, Mn, Ti, and Sc.

[0080] For example, the saturation magnetization of the third magnetic layer 23 is higher than that of the second magnetic layer 22. This makes it easier to obtain stable oscillation, for example. The boundary between the third magnetic layer 23 and the first magnetic layer 21 may be clear or unclear. The third magnetic layer 23 may be continuous with the second magnetic layer 22.

[0081] In the magnetic head 112, the first thickness t1 of the first magnetic layer 21 is, for example, 0.8 to 1.25 times the sum of the third thickness t3 of the third magnetic layer 23 and the second thickness t2 of the second magnetic layer 22, which are aligned in the first direction (from the first magnetic pole 31 to the second magnetic pole 32). For example, high oscillation intensity can be obtained. Stable oscillation can be obtained.

[0082] The following describes examples of magnetic heads and magnetic recording media 80 included in the magnetic recording device 210 according to the embodiment. Figure 9 is a schematic cross-sectional view illustrating a magnetic head according to an embodiment. As shown in Figure 9, in the magnetic head according to the embodiment (for example, magnetic head 110), the first direction D1 from the first magnetic pole 31 to the second magnetic pole 32 may be inclined with respect to the X-axis direction. The first direction D1 corresponds to the stacking direction of the magnetic element 20. The X-axis direction is along the medium-facing surface 30F. The angle between the first direction D1 and the medium-facing surface 30F is denoted as angle θ1. Angle θ1 is, for example, 15 degrees or more and 30 degrees or less. Angle θ1 may also be 0 degrees.

[0083] When the first direction D1 is inclined with respect to the X-axis direction, the thickness of the layer corresponds to the length along the first direction D1. The configuration in which the first direction D1 is inclined with respect to the X-axis direction may be applied to any magnetic head according to the embodiment. For example, the interface between the first magnetic pole 31 and the magnetic element 20, and the interface between the magnetic element 20 and the second magnetic pole 32 may be inclined with respect to the X-axis direction.

[0084] The following describes examples of magnetic heads and magnetic recording media 80 included in the magnetic recording device 210 according to the embodiment.

[0085] Figure 10 is a schematic perspective view illustrating a magnetic recording device according to an embodiment. As shown in Figure 10, the magnetic head according to the embodiment (for example, magnetic head 110) is used together with a magnetic recording medium 80. In this example, the magnetic head 110 includes a recording unit 60 and a playback unit 70. The recording unit 60 of the magnetic head 110 records information on the magnetic recording medium 80. The playback unit 70 reproduces the information recorded on the magnetic recording medium 80.

[0086] The magnetic recording medium 80 includes, for example, a media substrate 82 and a magnetic recording layer 81 provided on the media substrate 82. The magnetization 83 of the magnetic recording layer 81 is controlled by the recording unit 60.

[0087] The regeneration unit 70 includes, for example, a first regeneration magnetic shield 72a, a second regeneration magnetic shield 72b, and a magnetic regeneration element 71. The magnetic regeneration element 71 is provided between the first regeneration magnetic shield 72a and the second regeneration magnetic shield 72b. The magnetic regeneration element 71 is capable of outputting a signal corresponding to the magnetization 83 of the magnetic recording layer 81.

[0088] As shown in Figure 10, the magnetic recording medium 80 moves relative to the magnetic head 110 in the direction of the medium movement direction 85. The magnetic head 110 controls the information corresponding to the magnetization 83 of the magnetic recording layer 81 at any position. The magnetic head 110 reproduces the information corresponding to the magnetization 83 of the magnetic recording layer 81 at any position.

[0089] Figure 11 is a schematic perspective view illustrating a part of a magnetic recording apparatus according to an embodiment. Figure 11 illustrates a head slider. The magnetic head 110 is mounted on a head slider 159. The head slider 159 includes, for example, Al2O3 / TiC. The head slider 159 moves relative to the magnetic recording medium, either floating above or in contact with it.

[0090] The head slider 159 has, for example, an air inlet side 159A and an air outlet side 159B. The magnetic head 110 is positioned on the side of the air outlet side 159B of the head slider 159. As a result, the magnetic head 110 moves relative to the magnetic recording medium while floating above or in contact with it.

[0091] Figure 12 is a schematic perspective view illustrating a magnetic recording device according to an embodiment. As shown in Figure 12, a rotary actuator is used in the magnetic recording device 150 according to this embodiment. The recording medium disk 180 is mounted on a spindle motor 180M. The recording medium disk 180 rotates in the direction of arrow AR by the spindle motor 180M. The spindle motor 180M responds to a control signal from the drive unit control. The magnetic recording device 150 according to this embodiment may include a plurality of recording medium disks 180. The magnetic recording device 150 may also include a recording medium 181. The recording medium 181 is, for example, an SSD (Solid State Drive). For example, a non-volatile memory such as flash memory is used for the recording medium 181. For example, the magnetic recording device 150 may also be a hybrid HDD (Hard Disk Drive).

[0092] The head slider 159 records and plays back information to be recorded on the recording medium disk 180. The head slider 159 is located at the tip of a thin-film suspension 154. A magnetic head according to this embodiment is located near the tip of the head slider 159.

[0093] As the recording medium disk 180 rotates, the pressing pressure from the suspension 154 and the pressure generated on the media-facing surface (ABS) of the head slider 159 are balanced. The distance between the media-facing surface of the head slider 159 and the surface of the recording medium disk 180 becomes a predetermined amount of levitation. In this embodiment, the head slider 159 may be in contact with the recording medium disk 180. For example, a contact-running type may be applied.

[0094] The suspension 154 is connected to one end of an arm 155 (for example, an actuator arm). The arm 155 has, for example, a bobbin section. The bobbin section 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 a type of linear motor. The voice coil motor 156 includes, for example, a drive coil and a magnetic circuit. The drive coil is wound around the bobbin section 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 the other end. A magnetic head is provided at one end of the suspension 154. The arm 155 is connected to the other end of the suspension 154.

[0095] The arm 155 is held by ball bearings. Ball bearings are provided at two locations, above and below the bearing portion 157. The arm 155 can rotate and slide by a voice coil motor 156. The magnetic head can move to any position on the recording medium disk 180.

[0096] Figures 13(a) and 13(b) are schematic perspective views illustrating a part of a magnetic recording apparatus according to an embodiment. Figure 13(a) illustrates a part of the configuration of a magnetic recording device and is an enlarged perspective view of the head stack assembly 160. Figure 13(b) is a perspective view illustrating a magnetic head assembly (head gimbal assembly: HGA) 158, which is part of the head stack assembly 160.

[0097] As shown in Figure 13(a), the head stack assembly 160 includes a bearing section 157, a head gimbal assembly 158, and a support frame 161. The head gimbal assembly 158 extends from the bearing section 157. The support frame 161 extends from the bearing section 157. The direction in which the support frame 161 extends is opposite to the direction in which the head gimbal assembly 158 extends. The support frame 161 supports the coil 162 of the voice coil motor 156.

[0098] As shown in Figure 13(b), the head gimbal assembly 158 includes an arm 155 extending from a bearing portion 157 and a suspension 154 extending from the arm 155.

[0099] A head slider 159 is provided at the tip of the suspension 154. A magnetic head according to the embodiment is provided on the head slider 159.

[0100] The magnetic head assembly (head gimbal assembly) 158 according to the embodiment includes a magnetic head according to the embodiment, a head slider 159 on which the magnetic head is provided, a suspension 154, and an 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.

[0101] The suspension 154 may have, for example, lead wires (not shown) for recording and reproducing signals. The suspension 154 may also have, for example, lead wires (not shown) for heaters for adjusting the amount of levitation. The suspension 154 may also have, for example, lead wires (not shown) for a spin transfer torque oscillator. These lead wires are electrically connected to a plurality of electrodes provided on the magnetic head.

[0102] A signal processing unit 190 is provided in the magnetic recording device 150. The signal processing unit 190 records and reproduces signals on a magnetic recording medium using a magnetic head. The input and output lines of the signal processing unit 190 are connected, for example, to the electrode pads of the head gimbal assembly 158 and are electrically connected to the magnetic head.

[0103] The magnetic recording apparatus 150 according to the embodiment includes a magnetic recording medium, a magnetic head according to the embodiment, a movable part, a position control unit, and a signal processing unit. The movable part allows the magnetic recording medium and the magnetic head to move relative to each other while separated or in contact. The position control unit aligns the magnetic head to a predetermined recording position on the magnetic recording medium. The signal processing unit records and reproduces signals on the magnetic recording medium using the magnetic head.

[0104] For example, a recording medium disk 180 is used as the magnetic recording medium. The movable part includes, for example, a head slider 159. The position control unit includes, for example, a head gimbal assembly 158.

[0105] The embodiments may include the following technical proposals. (Technical proposal 1) Magnetic head and Control unit and Equipped with, The aforementioned magnetic head is The first magnetic pole and, The second magnetic pole and, A magnetic element provided between the first magnetic pole and the second magnetic pole, Coil and, First terminal and, The second terminal and Includes, The first terminal is electrically connected to a part of the magnetic element, The second terminal is electrically connected to another part of the magnetic element, The aforementioned magnetic circuit is The first magnetic layer and A second magnetic layer is provided between the first magnetic layer and the second magnetic pole, A first non-magnetic layer is provided between the first magnetic layer and the second magnetic layer, A second non-magnetic layer is provided between the second magnetic layer and the second magnetic pole, A third non-magnetic layer is provided between the first magnetic pole and the first magnetic layer, Includes, When a first coil current of a first frequency is supplied to the coil and a first current is supplied between the first terminal and the second terminal, a first signal having a first signal intensity of a first component of the first frequency is generated between the first terminal and the second terminal. When the first coil current is supplied to the coil and a second current is supplied between the first terminal and the second terminal, a second signal having a second signal strength of the second component of the first frequency is generated between the first terminal and the second terminal. The absolute value of the first coil current is greater than or equal to the coil current value. The first current has a first direction from the first magnetic layer to the second magnetic layer, The second current has a second direction from the second magnetic layer to the first magnetic layer, The second absolute value of the second current is the same as the first absolute value of the first current. When the first absolute value is changed, the change in the absolute value of the difference between the time integration of the first signal intensity and the time integration of the second signal intensity includes the first and second peaks. The first absolute value of the first current corresponds to the first peak, The second current value of the first absolute value corresponds to the second peak, The first current value is greater than the second current value. The control unit is configured to perform the first operation, In the first operation, the control unit is configured to supply a recording element current to the magnetic element while simultaneously supplying a recording coil current to the coil. The absolute value of the coil current during recording is greater than or equal to the coil current value. A magnetic recording device in which the element current during recording is less than or equal to the first current value.

[0106] (Technical proposal 2) The magnetic recording apparatus according to Technical Proposal 1, wherein the element current during recording is greater than or equal to the second current value.

[0107] (Technical proposal 3) The magnetic recording device according to Technical Proposal 1 or 2, wherein the first current value is 2.5 times or more and 3.5 times or less the second current value.

[0108] (Technical proposal 4) When a DC second coil current is supplied to the coil and the magnitude of the third current supplied between the first and second terminals changes, the change in the differential resistance of the magnetic element with respect to the change in the magnitude of the third current includes a valley in the third current of the first valley current value. The absolute value of the second coil current is greater than or equal to the coil current value. The third current has the first direction, The magnetic recording apparatus according to any one of Technical Proposals 1 to 3, wherein the element current during recording is less than or equal to the first valley current value.

[0109] (Technical proposal 5) The magnetic recording device according to Technical Proposal 4, wherein the first valley current value is 2.5 times or more and 3.5 times or less the second current value.

[0110] (Technical proposal 6) Magnetic head and Control unit and Equipped with, The aforementioned magnetic head is The first magnetic pole and, The second magnetic pole and, A magnetic element provided between the first magnetic pole and the second magnetic pole, Coil and, First terminal and, The second terminal and Includes, The first terminal is electrically connected to a part of the magnetic element, The second terminal is electrically connected to another part of the magnetic element, The aforementioned magnetic circuit is The first magnetic layer and A second magnetic layer is provided between the first magnetic layer and the second magnetic pole, A first non-magnetic layer is provided between the first magnetic layer and the second magnetic layer, A second non-magnetic layer is provided between the second magnetic layer and the second magnetic pole, A third non-magnetic layer is provided between the first magnetic pole and the first magnetic layer, Includes, When a DC second coil current is supplied to the coil and the magnitude of the third current supplied between the first and second terminals changes, the change in the differential resistance of the magnetic element with respect to the change in the magnitude of the third current includes a valley in the third current of the first valley current value. The absolute value of the second coil current is greater than or equal to the coil current value. The third current has a first direction from the first magnetic layer to the second magnetic layer, The control unit is configured to perform the first operation, In the first operation, the control unit is configured to supply a recording element current to the magnetic element while simultaneously supplying a recording coil current to the coil. The absolute value of the coil current during recording is greater than or equal to the coil current value. A magnetic recording device in which the element current during recording is less than or equal to the first valley current value.

[0111] (Technical proposal 7) The magnetic recording apparatus according to Technical Proposal 6, wherein the element current during recording is 0.3 times or more the first valley current value.

[0112] (Technical proposal 8) The first magnetic layer comprises a first element including at least one of Fe, Co, and Ni. The second magnetic layer comprises the first element and a second element which includes at least one selected from the group consisting of Cr, V, Mn, Ti, and Sc. A magnetic recording apparatus according to any one of Technical Proposals 1 to 7, wherein the first magnetic layer does not contain the second element, or the concentration of the second element in the first magnetic layer is lower than the concentration of the second element in the second magnetic layer.

[0113] (Technical proposal 9) The magnetic element further includes a third magnetic layer, The third magnetic layer is provided between the second magnetic layer and the second non-magnetic layer. The third magnetic layer comprises at least one of Fe, Co, and Ni. The magnetic recording apparatus according to Technical Proposal 8, wherein the third magnetic layer does not contain the second element, or the concentration of the second element in the third magnetic layer is lower than the concentration of the second element in the second magnetic layer.

[0114] (Technical proposal 10) The magnetic recording apparatus according to Technical Proposal 8 or 9, wherein the concentration of the second element in the second magnetic layer is 10 atomic% or more and 80 atomic% or less.

[0115] (Technical proposal 11) A magnetic recording apparatus according to any one of Technical Proposals 1 to 10, wherein the first thickness of the first magnetic layer along the first direction from the first magnetic pole to the second magnetic pole is 0.25 times or more and 4 times or less the second thickness of the second magnetic layer along the first direction.

[0116] (Technical proposal 12) The first magnetic layer includes a first magnetic region and a second magnetic region. The second magnetic region is located between the first magnetic region and the first non-magnetic layer. A magnetic recording apparatus according to any one of Technical Proposals 1 to 11, wherein the saturation magnetization of the first magnetic region is greater than the saturation magnetization of the second magnetic region.

[0117] (Technical proposal 13) The second magnetic layer includes a third magnetic region and a fourth magnetic region. The fourth magnetic region is located between the third magnetic region and the first non-magnetic layer. A magnetic recording apparatus according to any one of Technical Proposals 1 to 12, wherein the saturation magnetization of the third magnetic region is greater than the saturation magnetization of the fourth magnetic region.

[0118] (Technical proposal 14) The magnetic recording apparatus according to any one of the technical proposals 1 to 13, wherein the third non-magnetic layer is in contact with the first magnetic pole and the first magnetic layer.

[0119] (Technical proposal 15) The magnetic recording apparatus according to any one of Technical Proposals 1 to 14, wherein the first non-magnetic layer is in contact with the first magnetic layer and the second magnetic layer.

[0120] (Technical proposal 16) The second non-magnetic layer is in contact with the second magnetic layer and the second magnetic pole, as described in any one of Technical Proposals 1 to 8, in the magnetic recording apparatus.

[0121] (Technical proposal 17) A magnetic recording apparatus according to any one of the Technical Proposals 1 to 16, wherein at least one of the first non-magnetic layer, the second non-magnetic layer, and the third non-magnetic layer contains a third element, which includes at least one selected from the group consisting of Cu, Au, Cu, V, Al, and Ag.

[0122] (Technical proposal 18) The first magnetic layer includes a first magnetic region and a second magnetic region. The second magnetic region is located between the first magnetic region and the first non-magnetic layer. A magnetic recording apparatus according to any one of Technical Proposals 1 to 11, wherein the concentration of Fe in the first magnetic region is higher than the concentration of Fe in the second magnetic region.

[0123] (Technical proposal 19) The second magnetic layer includes a third magnetic region and a fourth magnetic region. The fourth magnetic region is located between the third magnetic region and the first non-magnetic layer. A magnetic recording apparatus according to any one of Technical Proposals 1 to 12, wherein the concentration of Fe in the third magnetic region is higher than the concentration of Fe in the fourth magnetic region.

[0124] (Technical proposal 20) A magnetic recording apparatus according to any one of Technical Proposals 1 to 19, wherein an alternating magnetic field is generated from the magnetic element in the first operation.

[0125] According to this embodiment, a magnetic recording device capable of improving recording density can be provided.

[0126] In this specification, "perpendicular" and "parallel" do not mean strictly perpendicular and strictly parallel, but also include variations in the manufacturing process, for example, and it is sufficient if they are substantially perpendicular and substantially parallel.

[0127] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configuration of each element included in a magnetic recording device, such as a magnetic head, magnetic poles, magnetic elements, magnetic layers, non-magnetic layers, wiring, magnetic recording media, and control unit, is included within the scope of the present invention as long as those skilled in the art can appropriately select from the known range to implement the present invention and obtain similar effects.

[0128] Combinations of two or more elements from any of the specific examples, to the extent technically feasible, are also included within the scope of the present invention, insofar as they encompass the gist of the invention.

[0129] Furthermore, all magnetic recording devices that can be implemented by those skilled in the art by appropriately modifying the design based on the magnetic recording device described above as an embodiment of the present invention also fall within the scope of the present invention, insofar as they encompass the gist of the present invention.

[0130] Furthermore, within the scope of the concept of the present invention, a person skilled in the art could conceive of various modifications and alterations, and it is understood that such modifications and alterations also fall within the scope of the present invention.

[0131] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0132] 10D: Control unit, 20: Magnetic element, 20D: Element electrical circuit, 21~23: First to third magnetic layers, 21a, 21b: First and second magnetic regions, 22c, 22d: Third and fourth magnetic regions, 30D: Recording circuit, 30F: Media-facing surface, 30c: Coil, 30i: Insulation part, 31, 32: First and second magnetic poles, 33: Shield, 41~43: First to third non-magnetic layers, 60: Recording unit, 70: Reproduction unit, 71: Magnetic reproduction element, 72a, 72b: First and second reproduction magnetic shields, 80: Magnetic recording medium, 81: Magnetic recording layer, 82: Media substrate, 83: Magnetization, 85: Media movement direction, 110~112: Magnetic head, 150: Magnetic recording device, 154: Suspension, 155: Arm, 156: Voice coil motor, 157: Bearing section, 158: Head gimbal assembly, 159: Head slider, 159A: Air inlet side, 159B: Air outlet side, 160: Head stack assembly, 161: Support frame, 162: Coil, 180: Recording medium disk, 180M: Spindle motor, 181: Recording medium, 190: Signal processing unit, 210: Magnetic recording device, AR, AR1: Arrow, D1: First direction, Ic1, Ic2: First and second coil currents, Icth: Coil current value, Id1~Id3: First to third currents, Idw: Element current during recording, Iu1: First current value, Iv1, Iv2: First and second current values, Iw0: Coil current during recording, Rd1: Differential resistance, SS1~SS3: 1st~3rd signal strength, Sg1~Sg3: 1st~3rd signal, T1, T2: 1st and 2nd terminals, Tf1: period, Vb1: valley, W1, W2: 1st and 2nd wiring, f1: 1st frequency, je: electron current, pk1, pk2: 1st and 2nd peaks, t1~t3: 1st~3rd thickness, tm: time, t41~t43: thickness, θ1: angle

Claims

1. Magnetic head and Control unit and Equipped with, The magnetic head is The first magnetic pole and, The second magnetic pole and, A magnetic element provided between the first magnetic pole and the second magnetic pole, Coil and, First terminal and, The second terminal and, Includes, The first terminal is electrically connected to a part of the magnetic element, The second terminal is electrically connected to another part of the magnetic element. The aforementioned magnetic circuit is The first magnetic layer and A second magnetic layer is provided between the first magnetic layer and the second magnetic pole, A first non-magnetic layer is provided between the first magnetic layer and the second magnetic layer, A second non-magnetic layer is provided between the second magnetic layer and the second magnetic pole, A third non-magnetic layer is provided between the first magnetic pole and the first magnetic layer, Includes, When a first coil current of a first frequency is supplied to the coil and a first current is supplied between the first terminal and the second terminal, a first signal having a first signal strength of a first component of the first frequency is generated between the first terminal and the second terminal. When the first coil current is supplied to the coil and a second current is supplied between the first terminal and the second terminal, a second signal having a second signal strength of the second component of the first frequency is generated between the first terminal and the second terminal. The absolute value of the first coil current is greater than or equal to the coil current value. The first current has a first direction from the first magnetic layer to the second magnetic layer, The second current has a second direction from the second magnetic layer to the first magnetic layer, The second absolute value of the second current is the same as the first absolute value of the first current. When the first absolute value is changed, the change in the absolute value of the difference between the time integration of the first signal intensity and the time integration of the second signal intensity includes the first peak and the second peak. The first absolute value of the first current corresponds to the first peak, The second current value of the first absolute value corresponds to the second peak, The first current value is greater than the second current value. The control unit is configured to perform the first operation, In the first operation, the control unit is configured to supply a recording element current to the magnetic element while simultaneously supplying a recording coil current to the coil. The absolute value of the coil current during recording is greater than or equal to the coil current value. A magnetic recording device in which the element current during recording is less than or equal to the first current value.

2. The magnetic recording apparatus according to claim 1, wherein the element current during recording is greater than or equal to the second current value.

3. The magnetic recording apparatus according to claim 1, wherein the first current value is 2.5 times or more and 3.5 times or less the second current value.

4. When a DC second coil current is supplied to the coil and the magnitude of the third current supplied between the first terminal and the second terminal changes, the change in the differential resistance of the magnetic element with respect to the change in the magnitude of the third current includes a valley in the third current of the first valley current value. The absolute value of the second coil current is greater than or equal to the coil current value. The third current has the first direction, The magnetic recording apparatus according to claim 1, wherein the element current during recording is less than or equal to the first valley current value.

5. The magnetic recording apparatus according to claim 4, wherein the first valley current value is 2.5 times or more and 3.5 times or less the second current value.

6. Magnetic head and Control unit and Equipped with, The magnetic head is The first magnetic pole and, The second magnetic pole and, A magnetic element provided between the first magnetic pole and the second magnetic pole, Coil and, First terminal and, The second terminal and, Includes, The first terminal is electrically connected to a part of the magnetic element, The second terminal is electrically connected to another part of the magnetic element. The aforementioned magnetic circuit is The first magnetic layer and A second magnetic layer is provided between the first magnetic layer and the second magnetic pole, A first non-magnetic layer is provided between the first magnetic layer and the second magnetic layer, A second non-magnetic layer is provided between the second magnetic layer and the second magnetic pole, A third non-magnetic layer is provided between the first magnetic pole and the first magnetic layer, Includes, When a DC second coil current is supplied to the coil and the magnitude of the third current supplied between the first terminal and the second terminal changes, the change in the differential resistance of the magnetic element with respect to the change in the magnitude of the third current includes a valley in the third current of the first valley current value. The absolute value of the second coil current is greater than or equal to the coil current value. The third current has a first direction from the first magnetic layer to the second magnetic layer, The control unit is configured to perform the first operation, In the first operation, the control unit is configured to supply a recording element current to the magnetic element while simultaneously supplying a recording coil current to the coil. The absolute value of the coil current during recording is greater than or equal to the coil current value. A magnetic recording device in which the element current during recording is less than or equal to the first valley current value.

7. The magnetic recording apparatus according to claim 6, wherein the element current during recording is 0.3 times or more the first valley current value.

8. The first magnetic layer comprises a first element including at least one of Fe, Co, and Ni. The second magnetic layer comprises the first element and a second element which includes at least one selected from the group consisting of Cr, V, Mn, Ti, and Sc. The magnetic recording apparatus according to claim 1 or 6, wherein the first magnetic layer does not contain the second element, or the concentration of the second element in the first magnetic layer is lower than the concentration of the second element in the second magnetic layer.

9. The magnetic recording apparatus according to claim 1 or 6, wherein at least one of the first non-magnetic layer, the second non-magnetic layer, and the third non-magnetic layer contains a third element, which includes at least one selected from the group consisting of Cu, Au, Cu, V, Al, and Ag.

10. The magnetic recording apparatus according to claim 1 or 6, wherein an alternating magnetic field is generated from the magnetic element in the first operation.

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