JP7072036B2 - Magnetic recording head and magnetic recording / playback device - Google Patents

Description

Embodiments of the present invention relate to a magnetic recording head and a magnetic recording / reproducing device.

Information is recorded on a magnetic storage medium such as an HDD (Hard Disk Drive) using a magnetic recording head. It is desired to improve the recording density in the magnetic recording head and the magnetic recording / reproducing device.

Japanese Unexamined Patent Publication No. 2013-120610

An embodiment of the present invention provides a magnetic recording head and a magnetic recording / reproducing device capable of improving the recording density.

According to an embodiment of the present invention, the magnetic recording head includes a magnetic pole, a laminate, and a first non-magnetic layer. The laminated body is provided between the first magnetic layer, the second magnetic layer provided between the first magnetic layer and the magnetic pole, and between the first magnetic layer and the second magnetic layer. Includes a non-magnetic intermediate layer. The first non-magnetic layer is provided between the second magnetic layer and the magnetic pole, and is in contact with the magnetic pole and the second magnetic layer. The first magnetic layer has a first thickness along a first direction from the second magnetic layer toward the first magnetic layer, and a first saturation magnetic flux density. The second magnetic layer has a second thickness along the first direction and a second saturation magnetic flux density. The second product of the second thickness and the second saturated magnetic flux density is larger than the first product of the first thickness and the first saturated magnetic flux density. A current flows from the second magnetic layer toward the first magnetic layer.

1 (a) to 1 (c) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment. 2 (a) and 2 (b) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device of the first reference example. 3 (a) and 3 (b) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device of the second reference example. 4 (a) and 4 (b) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device of the third reference example. 5 (a) to 5 (d) are graphs illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device. 6 (a) to 6 (d) are graphs illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device. 7 (a) to 7 (d) are graphs illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device. FIG. 8 is a graph illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment. FIG. 9 is a graph illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment. FIG. 10 is a graph illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment. 11 (a) to 11 (c) are graphs illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment. 12 (a) to 12 (c) are schematic cross-sectional views illustrating another magnetic recording head and another magnetic recording / reproducing device according to the first embodiment. 13 (a) to 13 (c) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device according to the second embodiment. 14 (a) to 14 (c) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device according to the third embodiment. FIG. 15 is a schematic perspective view illustrating a part of the magnetic recording / reproducing device according to the fourth embodiment. FIG. 16 is a schematic perspective view illustrating the magnetic recording / reproducing device according to the embodiment. 17 (a) and 17 (b) are schematic perspective views illustrating a part of a magnetic recording / reproducing device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the sizes between the parts, etc. are not always the same as the actual ones. Even if the same part is represented, the dimensions and ratios may be different from each other depending on the drawing.
In the present specification and each figure, the same elements as those described above with respect to the above-mentioned figures are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.

(First Embodiment)
1 (a) to 1 (c) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment.
1 (b) and 1 (c) illustrate the state (operation) of the magnetic recording head and the magnetic recording / reproducing device.

As shown in FIG. 1A, the magnetic recording / reproducing device 150 according to the present embodiment includes the magnetic recording head 110 according to the present embodiment and the magnetic recording medium 80. The magnetic recording head 110 records information on the magnetic recording medium 80.

The magnetic recording head 110 includes a magnetic pole 20, a laminate 10, and a first non-magnetic layer 15.

The magnetic pole 20 applies a magnetic field (recording magnetic field) to the magnetic recording medium 80. The magnetic pole 20 is, for example, a main magnetic pole.

The laminated body 10 includes a first magnetic layer 11, a second magnetic layer 12, and an intermediate layer 13. The second magnetic layer 12 is provided between the first magnetic layer 11 and the magnetic pole 20. The intermediate layer 13 is provided between the first magnetic layer 11 and the second magnetic layer 12. The intermediate layer 13 is non-magnetic. As will be described later, the laminated body 10 generates a high frequency magnetic field. The high frequency magnetic field is applied to the magnetic recording medium 80. The recording of information on the magnetic recording medium 80 by the magnetic pole 20 is assisted by the high frequency magnetic field. In the magnetic recording head 110, for example, high frequency assist recording is performed. The laminate 10 functions as, for example, a spin torque oscillator (STO: Spin Torque Oscillator).

The first non-magnetic layer 15 is provided between the second magnetic layer 12 and the magnetic pole 20. The first non-magnetic layer 15 is in contact with the magnetic pole 20 and the second magnetic layer 12. No magnetic layer is provided between the magnetic pole 20 and the second magnetic layer 12. The first non-magnetic layer 15 is, for example, a metal layer. This metal layer may contain an alloy. The first non-magnetic layer 15 may include a plurality of laminated films (metal films).

In this example, the shield 20s and the second non-magnetic layer 16 are further provided. The laminated body 10 is arranged between the magnetic pole 20 and the shield 20s. The first non-magnetic layer 15 is arranged between the magnetic pole 20 and the laminated body 10. A second non-magnetic layer 16 is provided between the shield 20s and the laminated body 10. In this example, the second non-magnetic layer 16 is arranged between the first magnetic layer 11 and the shield 20s.

The second non-magnetic layer 16 is, for example, a metal layer. This metal layer may contain an alloy. The second non-magnetic layer 16 may include a plurality of laminated films (metal films).

The magnetic recording head 110 faces the magnetic recording medium 80. The magnetic recording head 110 has a medium facing surface 51 (ABS: Air Bearing Surface). The magnetic recording medium 80 moves relative to the medium facing surface 51 of the magnetic recording head 110. The medium moving direction 85 of the magnetic recording medium 80 is substantially parallel to the medium facing surface 51. As the magnetic recording medium 80 moves, a recording magnetic field is applied from the magnetic pole 20 to each of the different positions of the magnetic recording medium 80. The recording magnetic field changes the direction of the magnetization 84 of the magnetic recording medium 80.

The magnetic recording medium 80 is, for example, a perpendicular magnetization film. The state in which the magnetization 84 is upward corresponds to, for example, one of the information of "1" and "0". The downward state of the magnetization 84 corresponds to, for example, the other information of "1" and "0".

The shield 20s is, for example, a trailing shield. For example, one position of the magnetic recording medium 80 faces the shield 20s after facing the magnetic pole 20.

The magnetic recording head 110 is provided with a coil 25. The coil 25 generates a magnetic field from the magnetic pole 20. For example, the direction of the magnetic field (for example, the recording magnetic field) generated by the magnetic pole 20 changes according to the direction of the current flowing through the coil 25. The direction of the current flowing through the coil 25 corresponds to, for example, the information to be recorded.

In this example, a control unit 55 is further provided. The control unit 55 is included in the magnetic recording / playback device 150. The control unit 55 may be attached to the magnetic recording head 110.

The control unit 55 is electrically connected to the coil 25. For example, a current is supplied from the control unit 55 to the coil 25. The direction of the current is controlled by the control unit 55.

The control unit 55 is electrically connected to, for example, the first non-magnetic layer 15 and the second non-magnetic layer 16. As will be described later, a current flows through the laminated body 10. This current is supplied by, for example, the control unit 55. The first non-magnetic layer 15 and the second non-magnetic layer 16 function as electrodes, for example. The electrical connection between the control unit 55 and the first non-magnetic layer 15 may be made via the magnetic pole 20. The electrical connection between the control unit 55 and the second non-magnetic layer 16 may be made via the shield 20s.

The direction from the magnetic recording medium 80 toward the magnetic recording head 110 is the Z direction. One direction perpendicular to the Z direction is defined as the X direction. The direction perpendicular to the Z direction and the X direction is defined as the Y direction. The Z direction is the height direction. The X direction is along the downtrack direction. The Y direction is along the track width direction.

In the magnetic recording head 110, the direction from the second magnetic layer 12 to the first magnetic layer 11 is defined as the first direction D1. The direction from the first magnetic layer 11 to the second magnetic layer 12 is defined as the second direction D2. The second direction D2 is antiparallel to the first direction D1. The first direction D1 and the second direction D2 are, for example, along the X direction. The first direction D1, the second direction D2, and the X direction are along the stacking direction of the laminated body 10.

The first magnetic layer 11 has a first thickness t1 along the first direction D1. The second magnetic layer 12 has a second thickness t2 along the first direction D1. The intermediate layer 13 has a third thickness t3 along the first direction D1. For example, the thickness of the laminate 10 depends on, for example, the sum of the first thickness t1, the second thickness t2, and the third thickness t3.

For example, the gap length g20 is defined as the distance between the magnetic pole 20 and the shield 20s (distance along the first direction D1) on the medium facing surface 51. By reducing the gap length g20, the recording density can be improved. By reducing the thickness of the laminate 10, the gap length g20 can be reduced.

In the embodiment, the first thickness t1 of the first magnetic layer 11 is set to be relatively thin. As a result, the thickness of the laminated body 10 can be reduced, and the gap length g20 can be reduced.

In the magnetic film, the magnetic film thickness is defined. The magnetic film thickness is the product of the thickness t of the magnetic film and the saturation magnetic flux density Bs of the magnetic film.

In the embodiment, the magnetic film thickness of the second magnetic layer 12 is larger than the magnetic film thickness of the first magnetic layer 11. The first magnetic layer 11 has a first thickness t1 along the first direction D1 and a first saturation magnetic flux density Bs1. The second magnetic layer 12 has a second thickness t2 along the first direction D1 and a second saturation magnetic flux density Bs2. In the embodiment, the second product (t2 · Bs2) of the second thickness t2 and the second saturation magnetic flux density Bs2 is the first product (t1 · Bs1) of the first thickness t1 and the first saturation magnetic flux density Bs1. ) Greater than.

Further, in the embodiment, the current flowing through the laminated body 10 is set as a special condition. That is, in the embodiment, a current flows from the second magnetic layer 12 toward the first magnetic layer 11. Hereinafter, the operation according to the embodiment will be described.

FIG. 1B illustrates the first operation OP1. The first operation OP1 corresponds to the first state in the magnetic recording head 110. In the first operation OP1, the first coil current C1 flows through the coil 25. In the region between the magnetic pole 20 and the shield 20s, the direction of the first coil current C1 is, for example, opposite (antiparallel) to the Y direction.

In the first operation OP1 (first state), the first magnetic field magnetic field Hg1 generated from the magnetic pole 20 has a component along the first direction D1. At this time, the first current Jc1 in the first direction D1 flows through the laminated body 10. At this time, the first electron flow Je1 is flowed. The direction of the first electron flow Je1 is opposite to the direction of the first current Jc1. The first current Jc1 is equal to or higher than the threshold current oscillated by the laminated body 10. At this time, a high frequency magnetic field Hac is generated in the laminated body 10. The high frequency magnetic field Hac is applied to the magnetic recording medium 80. The high-frequency magnetic field Hac makes it easy for the magnetization 84 of the magnetic recording medium 80 to be reversed.

In the first operation OP1, the first recording magnetic field Hr1 is generated from the magnetic pole 20. The first recording magnetic field Hr1 is based on the first coil current C1. The first recording magnetic field Hr1 is applied to the magnetic recording medium 80. The magnetization 84 of the magnetic recording medium 80 is along the direction of the first recording magnetic field Hr1. For example, the magnetization 84 is inverted. For example, high frequency assist recording is performed. As a result, the first information (for example, one of "1" and "0") is recorded.

FIG. 1 (c) illustrates the second operation OP2. The second operation OP2 corresponds to the second state in the magnetic recording head 110. In the second operation OP2, the second coil current C2 flows through the coil 25. In the region between the magnetic pole 20 and the shield 20s, the direction of the second coil current C2 is, for example, the Y direction.

In the second operation OP2 (second state), the second magnetic field magnetic field Hg2 generated from the magnetic pole 20 has a component along the second direction D2 (reverse and antiparallel of the first direction D1). Also at this time, the first current Jc1 in the first direction D1 is passed through the laminated body 10. The first current Jc1 is equal to or higher than the threshold current oscillated by the laminated body 10. At this time, a high frequency magnetic field Hac is generated in the laminated body 10. The high frequency magnetic field Hac is applied to the magnetic recording medium 80. The high-frequency magnetic field Hac makes it easy for the magnetization 84 of the magnetic recording medium 80 to be reversed.

In the second operation OP2, the second recording magnetic field Hr2 is generated from the magnetic pole 20. The second recording magnetic field Hr2 is based on the second coil current C2. The second recording magnetic field Hr2 is applied to the magnetic recording medium 80. The magnetization 84 of the magnetic recording medium 80 is along the direction of the second recording magnetic field Hr2. For example, the magnetization 84 is inverted. For example, high frequency assist recording is performed. As a result, the second information (for example, the other of "1" and "0") is recorded.

As described above, in the embodiment, the first thickness t1 of the first magnetic layer 11 is set thin. Further, a current (first current Jc1) flows from the second magnetic layer 12 toward the first magnetic layer 11 in the laminated body 10. As a result, it was found that a high-frequency magnetic field Hac was generated from the laminated body 10.

In the embodiment, the gap length g20 is small due to the thin first magnetic layer 11. Then, in this configuration, a high frequency magnetic field Hac is generated from the laminated body 10 by passing a current in the above direction through the laminated body 10. With this high frequency magnetic field Hac, for example, high frequency assist recording is performed. Even if the gap length g20 is small, high frequency assist recording is possible.

According to the embodiment, a magnetic recording head and a magnetic recording / reproducing device capable of improving the recording density can be provided by a small gap length g20 and a high frequency magnetic field Hac.

An example of the operation of the laminated body 10 in the embodiment will be described.
FIG. 1A corresponds to, for example, a state (initial state) when no current is supplied to the coil 25. In this state, the direction of the magnetization 12 m of the second magnetic layer 12 is the Z direction. The second magnetic layer 12 is, for example, an in-plane magnetizing film. At this time, the direction of the magnetization 11 m of the first magnetic layer 11 is the −Z direction (the direction opposite to the Z direction (antiparallel)). The first magnetic layer 11 is, for example, an in-plane magnetizing film. The orientation of the magnetization 11 m of the first magnetic layer 11 is liable to change. This results in a first state and a second state.

In the first state (first operation OP1) exemplified in FIG. 1 (b), the spin is reflected at the interface between the second magnetic layer 12 and the intermediate layer 13 by the first electron flow Je1 in the second direction D2. The reflected spin proceeds to the first magnetic layer 11. Reflective spin torque is injected from the second magnetic layer 12 toward the first magnetic layer 11. The magnetization 11m of the first magnetic layer 11 is opposite to the direction of the first magnetic field magnetic field Hg1. Spins are injected from the first magnetic layer 11 toward the second magnetic layer 12 by the first electron flow Je1 in the second direction D2. In the second magnetic layer 12, the magnetization 12 m rotates. This creates a high frequency magnetic field Hac.

In the second state (second operation OP2) exemplified in FIG. 1 (c), the spin is reflected at the interface between the second magnetic layer 12 and the intermediate layer 13 by the first electron flow Je1 in the second direction D2. The reflected spin proceeds to the first magnetic layer 11. Reflective spin torque is injected from the second magnetic layer 12 toward the first magnetic layer 11. The magnetization 11m of the first magnetic layer 11 is opposite to the direction of the second magnetic field magnetic field Hg2. Spins are injected from the first magnetic layer 11 toward the second magnetic layer 12 by the first electron flow Je1 in the second direction D2. In the second magnetic layer 12, the magnetization 12 m rotates. This creates a high frequency magnetic field Hac.

The first magnetic layer 11 functions as, for example, a spin injection layer. The second magnetic layer 12 functions as, for example, a magnetic field generation layer.

In the embodiment, a current is passed from the second magnetic layer 12 toward the first magnetic layer 11. From this, it was found that good oscillation characteristics can be obtained even if the first magnetic layer 11 is made thin.

Hereinafter, examples of the characteristics of the embodiment will be described together with reference examples.
2 (a) and 2 (b) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device of the first reference example.
These figures show the configuration and operation of the magnetic recording head 119x of the first reference example.

The magnetic recording head 119x is also provided with the first magnetic layer 11, the second magnetic layer 12, and the intermediate layer 13. The configuration of these magnetic layers is the same as that of the magnetic recording head 110. In the magnetic recording head 119x, the current in operation is different from that of the magnetic recording head 110.

As shown in FIGS. 2A and 2B, a second current Jc2 flows from the first magnetic layer 11 to the second magnetic layer 12 in the first operation OP1 and the second operation OP2. At this time, a second electron current Je2 flows from the second magnetic layer 12 to the first magnetic layer 11. In the magnetic recording head 119x, since the first magnetic layer 11 is thin, the gap length g20 can be reduced. However, as will be described later, a good high frequency magnetic field is not generated. High frequency assist recording is difficult.

3 (a) and 3 (b) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device of the second reference example.
These figures show the configuration and operation of the magnetic recording head 119y of the second reference example.

The magnetic recording head 119y is also provided with the first magnetic layer 11, the second magnetic layer 12, and the intermediate layer 13. In the magnetic recording head 119y, the first magnetic layer 11 is thicker than that in the magnetic recording head 110. On the other hand, in the magnetic recording head 119y, the current in operation is the same as that of the magnetic recording head 110.

As shown in FIGS. 3A and 3B, a first current Jc1 flows from the second magnetic layer 12 to the first magnetic layer 11 in the first operation OP1 and the second operation OP2. At this time, the first electron current Je1 flows from the first magnetic layer 11 to the second magnetic layer 12. In the magnetic recording head 119y, since the first magnetic layer 11 is thick, the gap length g20 is large. As will be described later, a good high frequency magnetic field is not generated. High frequency assist recording is difficult.

4 (a) and 4 (b) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device of the third reference example.
These figures show the configuration and operation of the magnetic recording head 119z of the third reference example.

The magnetic recording head 119z is also provided with the first magnetic layer 11, the second magnetic layer 12, and the intermediate layer 13. In the magnetic recording head 119z, the first magnetic layer 11 is thicker than that in the magnetic recording head 110. Further, in the magnetic recording head 119z, the current in operation is the same as that of the magnetic recording head 119x, unlike that of the magnetic recording head 110.

As shown in FIGS. 4A and 4B, a second current Jc2 flows from the first magnetic layer 11 to the second magnetic layer 12 in the first operation OP1 and the second operation OP2. At this time, a second electron current Je2 flows from the second magnetic layer 12 to the first magnetic layer 11. In the magnetic recording head 119z, since the first magnetic layer 11 is thick, the gap length g20 is large. As will be described later, a good high frequency magnetic field is generated. The magnetic recording head 119z has a conventionally known general configuration. High-frequency assist recording is possible with the magnetic recording head 119z. However, the gap length g20 is large. Therefore, the recording density cannot be sufficiently improved.

Hereinafter, an example of simulation results of the characteristics of these magnetic recording heads (characteristics of the magnetic recording / reproducing device) will be described. The simulation model is as follows.

In the magnetic recording heads 110 and 119x, the length of the first magnetic layer 11 in the Z direction is 35 nm, and the length in the Y direction is 35 nm. The thickness of the first magnetic layer 11 in the X direction (first thickness t1) is 4 nm. The saturation magnetic flux density Bs (first saturation magnetic flux density Bs1) of the first magnetic layer 11 is 1.2T (tesla). The anisotropic magnetic field Hk of the first magnetic layer 11 is 2 kOe (kiloersted). The exchange stiffness constant in the first magnetic layer 11 is 1.4 × 10 ^-6 erg / cm (erg / centimeter). The spin polarization rate Po in the first magnetic layer 11 is 0.48.

In the magnetic recording heads 119y and 119z, the thickness of the first magnetic layer 11 in the X direction (first thickness t1) is 11 nm. In the magnetic recording heads 119y and 119z, the perpendicular magnetic anisotropy magnetic field Hk of the first magnetic layer 11 is 18 kOe. The other conditions of the first magnetic layer 11 in the magnetic recording heads 119y and 119z are the same as those of the magnetic recording heads 110 and 119x.

Except for the first magnetic layer 11, the structure of the laminated body 10 is the same in the magnetic recording heads 110, 119x, 119y and 119z.

The length of the second magnetic layer 12 in the Z direction is 35 nm, and the length in the Y direction is 35 nm. The thickness of the second magnetic layer 12 in the X direction (second thickness t2) is 10 nm. The saturation magnetic flux density Bs (second saturation magnetic flux density Bs2) of the second magnetic layer 12 is 2.2T. The vertical magnetic anisotropy magnetic field Hk of the second magnetic layer 12 is -4 kOe. The exchange stiffness constant in the second magnetic layer 12 is 2 × 10 ^-6 erg / cm. The spin polarization rate Po in the second magnetic layer 12 is 0.48.

The distance between the first magnetic layer 11 and the second magnetic layer 12 (third thickness t3 of the intermediate layer 13) is 2 nm. In the intermediate layer 13, the exchange coupling coefficient is 0.

In the magnetic field applied to the laminated body 10, the ratio (Hy / Hx) of the Y-direction component magnetic field to the X-direction component magnetic field is −10%. The magnetic field applied to the laminated body 10 is changed in the range of 0 kOe to 20 kOe. This magnetic field corresponds to a gap magnetic field (first magnetic field magnetic field Hg1, second magnetic field magnetic field Hg2, etc.).

The following example is a simulation result regarding the transition from the initial state to the first state (first operation OP1). In the initial state, no current is passed through the laminated body 10. Since the magnetic film thickness of the second magnetic layer 12 is relatively large, the magnetization 12 m of the second magnetic layer 12 is stable. The vertical magnetic anisotropy of the second magnetic layer 12 has a small positive value or a negative value. Therefore, in the magnetic recording heads 110, 119x, 119y, and 119z in the initial state, the direction of the magnetization 12m is the + Z direction.

In the magnetic recording heads 119y and 119z, the magnetic film thickness of the first magnetic layer 11 is relatively large. The vertical magnetic anisotropy magnetic field of the first magnetic layer 11 has a large positive value. Therefore, the orientation of the magnetization 11 m of the first magnetic layer 11 is stable. In the magnetic recording heads 119y and 119z in the initial state, the direction of the magnetization 11m is the first direction D1.

On the other hand, in the magnetic recording heads 110 and 119x, the magnetic film thickness of the first magnetic layer 11 is relatively small. The vertical magnetic anisotropy magnetic field of the first magnetic layer 11 is small. Therefore, the direction of the magnetization 11 m of the first magnetic layer 11 is parallel to the laminated surface of the laminated body 10. In the magnetic recording heads 110 and 119z in the initial state, the direction of the magnetization 11 m is the −Z direction. When a magnetic field along the first direction D1 is applied to the laminated body 10 when no current is passed, the average direction of the magnetization 11 m becomes the first direction D1.

In the simulation, the direction of the magnetic field (gap magnetic field Hgap) applied to the laminated body 10 is substantially the first direction D1.

The direction of the current flowing through the laminated body 10 in the first state (first operation OP1) differs depending on the magnetic recording head. In the magnetic recording heads 110 and 119y, the first current Jc1 in the first direction D1 is passed. In the magnetic recording heads 119x and 119z, a second current Jc2 in the second direction D2 is passed. In these currents, the magnitude (absolute value) of the current is changed.

The magnetic recording head 119z is a general STO, and the direction of the current also corresponds to a general case. The magnetic recording head 119y corresponds to the case where the direction of the current is opposite to that of the general STO. The magnetic recording head 119x corresponds to the case where the first magnetic layer 11 is thin in the direction of the current in a general STO. The magnetic recording head 110 corresponds to a case where the first magnetic layer 11 is thin and the direction of the current is opposite to that of a general STO current.

5 (a) to 5 (d) are graphs illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device.
5 (a) to 5 (d) correspond to the magnetic recording heads 110, 119x, 119y and 119z, respectively. The horizontal axis indicates the intensity (koe) of the gap magnetic field Hgap. The vertical axis shows the intensity (koe) of the high-frequency magnetic field Hac generated in the laminated body 10. In these figures, the case of four current densities J is shown.

As shown in FIG. 5D, in the magnetic recording head 119z, a high-frequency magnetic field Hac having a high intensity can be obtained even at a high current density J. As described above, in the magnetic recording head 119z (in the case of a general STO, in the case of a general current direction), a high frequency magnetic field Hac can be obtained.

As shown in FIG. 5C, in the magnetic recording head 119y, the intensity of the high frequency magnetic field Hac is substantially 0 at any current density J. As described above, in the magnetic recording head 119y (when the direction of the current is opposite in a general STO), the high frequency magnetic field Hac cannot be obtained. Therefore, in a general STO (when the first magnetic layer 11 is thick), the second current Jc2 is applied. That is, the configuration of the magnetic recording head 119z is used.

On the other hand, as shown in FIG. 5B, in the magnetic recording head 119x, the intensity of the high frequency magnetic field Hac is low even if the absolute value of the current density J is large. As described above, when the first magnetic layer 11 is thin, the high frequency magnetic field Hac cannot be substantially obtained by using the current direction (second current Jc2) applied in a general STO. Therefore, conventionally, it has been considered difficult to make the first magnetic layer 11 thin.

However, as shown in FIG. 5A, in the magnetic recording head 110 according to the embodiment, a high-frequency magnetic field Hac having a high intensity can be obtained when the current density J is large. As described above, in the embodiment, the direction opposite to the current direction (second current Jc2) in the general STO is used (first current Jc1). As a result, a good high-frequency magnetic field Hac can be obtained even when the first magnetic layer 11 is thin.

It is an original new idea of the inventor of the present application to use a current in a direction opposite to the direction of the current adopted in a general STO. Thereby, the high frequency magnetic field Hac can be generated by using the first magnetic layer 11. This makes it possible to provide a magnetic recording head and a magnetic recording / reproducing device capable of reducing the gap length g20 and improving the recording density.

6 (a) to 6 (d) are graphs illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device.
6 (a) to 6 (d) correspond to the magnetic recording heads 110, 119x, 119y and 119z, respectively. The horizontal axis indicates the intensity (koe) of the gap magnetic field Hgap. The vertical axis shows the resistance R1 in the laminated body 10. The resistance R1 is a relative value. The resistance R1 corresponds to an angle between the direction of the magnetization 11 m of the first magnetic layer 11 and the direction of the magnetization 12 m of the second magnetic layer 12. When the resistance R1 is high (for example, 1), the direction of the magnetization 11 m of the first magnetic layer 11 is antiparallel to the direction of the magnetization 12 m of the second magnetic layer 12. When the resistance R1 is low (for example, 0), the direction of the magnetization 11 m of the first magnetic layer 11 is parallel to the direction of the magnetization 12 m of the second magnetic layer 12.

As shown in FIGS. 6 (b) to 6 (d), in the magnetic recording heads 119x, 119y and 119z, the resistance R1 decreases as the gap magnetic field Hgap increases. This corresponds to an increase in the gap magnetic field Hgap and a decrease in the angle between the magnetization 11 m of the first magnetic layer 11 and the magnetization 12 m of the second magnetic layer 12. As the gap magnetic field Hgap increases, the degree to which these magnetizations become parallel to each other increases.

On the other hand, as shown in FIG. 6A, in the magnetic recording head 110, when the absolute value of the current density J is large, the resistance R1 increases with the increase of the gap magnetic field Hgap. This corresponds to the fact that the magnetization 11 m of the first magnetic layer 11 is reversed from the initial state when the gap magnetic field Hgap becomes large when a current density of a certain high absolute value (a certain large current) is passed. At such a current density J, the high-frequency magnetic field Hac shown in FIG. 5A can be obtained.

In the embodiment, for example, a third magnetic field (gap magnetic field Hgap) having the component of the first direction D1 is applied while passing a first current Jc1 through the laminated body 10. At this time, the electric resistance (resistance R1) between the first magnetic layer 11 and the second magnetic layer 12 increases with the strength of the third magnetic field. That is, the electric resistance between the first magnetic layer 11 and the second magnetic layer 12 when a current (first current Jc1) is passed through the laminated body 10 increases with the strength of the magnetic field having the component in the first direction D1. do.

For example, in the magnetic recording head 110 according to the embodiment, a third magnetic field (gap magnetic field) having a size in the first range and having a component in the first direction D1 while passing a third current in the first direction D1 through the laminated body 10. Hgap) is applied. The third current is the current corresponding to the current density J in FIG. 6A. At this time, the electric resistance (resistance R1) between the first magnetic layer 11 and the second magnetic layer 12 increases with the strength of the third magnetic field. In the example of FIG. 6A, the range of the third current corresponds to the range in which the absolute value of the current density J is 4 × 10 ⁸ A / cm ² or more. The first current Jc1 is set in such a range. That is, the magnitude of the first current Jc1 is in this first range. As a result, a good high-frequency magnetic field Hac can be obtained in the first operation OP1.

7 (a) to 7 (d) are graphs illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device.
7 (a) to 7 (d) correspond to the magnetic recording heads 110, 119x, 119y and 119z, respectively. The horizontal axis indicates the intensity (koe) of the gap magnetic field Hgap. The vertical axis indicates the direction M1 of the magnetization 11 m of the first magnetic layer 11. When the orientation M1 is "1", the magnetization 11m corresponds to the first direction D1. When the orientation M1 is "-1", the magnetization 11m corresponds to the second direction D2.

As shown in FIGS. 7 (c) and 7 (d), in the magnetic recording heads 119y and 119z, the orientation M1 of the magnetization 11 m of the first magnetic layer 11 is 1. In these magnetic recording heads, the direction M1 with a magnetization of 11 m is the first direction D1 without depending on the current and the gap magnetic field Hgap. In these magnetic recording heads, the orientation of the magnetization 11 m does not change.

As shown in FIG. 7B, in the magnetic recording head 119x, when the gap magnetic field Hgap is 0 at any current density J, the direction (average direction) of the magnetization 11 m is 0. When the gap magnetic field Hgap is increased, the direction M1 approaches 1. That is, the direction M1 having a magnetization of 11 m is along the first direction D1.

As shown in FIG. 7A, in the magnetic recording head 110, when the current density J is 0 and the gap magnetic field Hgap is 0, the direction (average direction) of the magnetization 11 m is 0. When the current density J is 0 and the gap magnetic field Hgap is increased, the direction M1 approaches 1. That is, the direction M1 having a magnetization of 11 m is along the first direction D1. On the other hand, when the current density J is not 0 and the gap magnetic field Hgap is increased, the direction M1 approaches -1. That is, the direction M1 having a magnetization of 11 m changes in the second direction D2. This characteristic is peculiar to the magnetic recording head 110.

As described above, in the embodiment, the magnetization 11 m of the first magnetic layer 11 has a unique characteristic. As a result, a good high-frequency magnetic field Hac can be obtained even when the first magnetic layer 11 is thin.

FIG. 8 is a graph illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment.
FIG. 8 shows the frequency of the high frequency magnetic field Hac generated in the magnetic recording head 110. The horizontal axis indicates the intensity (koe) of the gap magnetic field Hgap. The vertical axis shows the frequency f1 (GHz: gigahertz) of the high frequency magnetic field Hac.

In the embodiment, the gap magnetic field Hgap is set to, for example, 7 kOe to 20 kOe. At this time, a stable high-frequency magnetic field Hac can be obtained. The frequency f1 of this high-frequency magnetic field Hac is, for example, 5 GHz or more and 25 GHz or less.

As described above, also in the present embodiment, the high frequency magnetic field Hac can be obtained even if the first magnetic layer 11 is thinned.

For example, in the first state (first operation OP1), the magnetization 11 m of the first magnetic layer 11 has a component in the second direction D2. In the first state, the direction of the magnetization 11 m is antiparallel to the direction of the first magnetic field magnetic field Hg1. On the other hand, in the second state (second operation OP2), the magnetization 11 m of the first magnetic layer 11 has a component in the first direction D1. In the second state, the direction of the magnetization 11 m is antiparallel to the direction of the second magnetic field magnetic field Hg2.

In the embodiment, in such a first state and a second state, the laminated body 10 generates a high frequency magnetic field Hac.

As described above, the first product (t1 · Bs1) of the first magnetic layer 11 is smaller than the second product (t2 · Bs2) of the second magnetic layer 12. For example, the second product is four times or more the first product. For example, the second thickness t2 is at least twice the first thickness t1.

FIG. 9 is a graph illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment.
FIG. 9 shows the oscillation characteristics of the magnetic recording head 110. The horizontal axis indicates the thickness of the first magnetic layer 11 (first thickness t1). The vertical axis indicates the current density J (arbitrary scale). In FIG. 9, the oscillation start current density Js and the 80% current density J80% are shown. The oscillation start current density Js is the minimum current density J in which the high frequency magnetic field Hac is generated in the laminated body 10. 80% current density J 80% is a current density J in which a high frequency magnetic field Hac of 80% of the maximum value of the high frequency magnetic field Hac is generated. In the example shown in FIG. 9, the magnetic field (gap magnetic field Hgap) applied to the laminated body 10 is 10 kOe. The gap magnetic field Hgap corresponds to, for example, a first magnetic field magnetic field Hg1 or a second magnetic field magnetic field Hg2.

As shown in FIG. 9, when the first thickness t1 of the first magnetic layer 11 is 2 nm or more and 9 nm or less, a low oscillation start current density Js can be obtained. Then, in this range, a low 80% current density J80% can be obtained. In the embodiment, the first thickness t1 of the first magnetic layer 11 is preferably 2 nm or more and 9 nm or less. The first thickness t1 of the first magnetic layer 11 is more preferably 2.5 nm or more and 7.5 nm or less. Further, a low oscillation start current density Js and a lower 80% current density J80% can be obtained.

FIG. 10 is a graph illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment.
FIG. 10 shows the oscillation characteristics of the magnetic recording head 110. The horizontal axis is the vertical magnetic anisotropy magnetic field MA1 (koe) of the first magnetic layer 11. The vertical axis indicates the current density J (arbitrary scale). The vertical magnetic anisotropy magnetic field MA1 is a vertical magnetocrystalline anisotropy. When the vertical magnetic anisotropy magnetic field MA1 is negative, magnetization to a plane perpendicular to the stacking direction becomes easy. When the perpendicular magnetic anisotropy magnetic field MA1 is positive, magnetization in the direction parallel to the stacking direction becomes easy. In FIG. 10, the oscillation start current density Js and the 80% current density J80% are shown. In the example shown in FIG. 10, the magnetic field (gap magnetic field Hgap) applied to the laminated body 10 is 10 kOe.

As shown in FIG. 10, when the perpendicular magnetic anisotropy magnetic field MA1 of the first magnetic layer 11 is −7 kOe or more and 8 kOe or less, a low oscillation start current density Js can be obtained. Then, in this range, a low 80% current density J80% can be obtained. In the embodiment, the vertical magnetic anisotropy magnetic field MA1 of the first magnetic layer 11 is preferably −7 kOe or more and 8 kOe or less. It is more preferable that the vertical magnetic anisotropy magnetic field MA1 of the first magnetic layer 11 is −5 kOe or more and 7 kOe or less. Further, a low oscillation start current density Js and a lower 80% current density J80% can be obtained. For example, the absolute value of the vertical magnetic anisotropy magnetic field MA1 of the first magnetic layer 11 may be 7 kOe or less. The absolute value of the vertical magnetic anisotropy magnetic field MA1 of the first magnetic layer 11 may be 5 kOe or less.

11 (a) to 11 (c) are graphs illustrating the characteristics of the magnetic recording head and the magnetic recording / reproducing device according to the first embodiment.
These figures show the oscillation characteristics of the magnetic recording head 110. In FIG. 11A, the horizontal axis is the ratio R2 / 1 of the magnetic damping volume of the second magnetic layer 12 to the magnetic damping volume of the first magnetic layer 11. The first magnetic layer 11 has a first damping constant α1. The second magnetic layer 12 has a second damping constant α2. As described above, the first magnetic layer 11 has a first thickness t1 and a first saturation magnetic flux density Bs1. The second magnetic layer 12 has a second thickness t2 and a second saturation magnetic flux density Bs2. The ratio R2 / 1 is (α2, t2, Bs2) / (α1, t1, Bs1). The vertical axis of FIG. 11B is the normalized intensity Hacn of the high frequency magnetic field Hac generated from the laminated body 10.

As shown in FIG. 11A, a high intensity Hacn can be obtained when the ratio R2 / 1 is 4 or more and 16 or less. The ratio R2 / 1 is preferably 4 or more and 16 or less. The ratio R2 / 1 is more preferably 5 or more and 14 or less.

In the embodiment, for example, the product of the second product (t2 · Bs2) and the second damping constant α2 is 4 times or more and 16 times or less the product of the first product (t1 · Bs1 and the first damping constant α1). Is preferable.

In FIG. 11B, the horizontal axis is the ratio RtBs of the magnetic film thickness of the second magnetic layer 12 to the magnetic film thickness of the first magnetic layer 11. The ratio RtBs corresponds to (t2 · Bs2) / (t1 · Bs1). The vertical axis of FIG. 11B is the intensity Hacn. In this example, the first damping constant α1 is 0.03 and the second damping constant α2 is 0.04.

As shown in FIG. 11B, high intensity Hacn can be obtained when the ratio RtBs is 3 or more and 11 or less. In the embodiment, the ratio RtBs is preferably, for example, 3 or more and 11 or less. In particular, the ratio RtBs is more preferably 4 or more and 10 or less, for example.

In FIG. 11C, the horizontal axis is the ratio Rt of the second magnetic layer 12 to the second thickness t2 and the first magnetic layer 11 to the first thickness t1. The ratio Rt corresponds to t2 / t1. The vertical axis of FIG. 11 (c) is the intensity Hacn. In this example, the first damping constant α1 is 0.03 and the second damping constant α2 is 0.04. The first saturation magnetic flux density Bs1 is 1.2T, and the second saturation magnetic flux density Bs2 is 2.2T.

As shown in FIG. 11 (c), a high intensity Hacn can be obtained when the ratio Rt is 1.5 or more and 7 or less. In the embodiment, the ratio Rt is preferably, for example, 1.5 or more and 7 or less. In particular, the ratio Rt is preferably, for example, 2 or more and 6 or less.

In the embodiment, the magnetic pole 20 includes, for example, a FeCo alloy, a FeCoNi alloy, or the like.

The shield 20s includes, for example, a FeCo alloy or a FeCoNi alloy.

At least one of the first magnetic layer 11 and the second magnetic layer 12 is, for example, a FeCo alloy, a Whistler alloy, a [Fe / Co] artificial lattice, a [FeCoNi / Ni] artificial lattice, and a [Co / Pt] artificial lattice. Includes at least one of. including. At least one of the first magnetic layer 11 and the second magnetic layer 12 is a FeCo alloy film, a Whistler alloy film, a [Fe / Co] artificial lattice film, a [FeCoNi / Ni] artificial lattice film, and [Co / Pt]. A laminated film containing at least two artificial lattice films may be included.

The intermediate layer 13 contains, for example, at least one of Cu and Ag. The intermediate layer 13 may contain, for example, at least one of an alloy containing Cu and an alloy containing Ag. The intermediate layer 13 may include, for example, a Cu film, an Ag film, an alloy film containing Cu, and a laminated film containing at least two of the alloy films containing Ag.

At least one of the first non-magnetic layer 15 and the second non-magnetic layer 16 includes, for example, at least one of Ta, Cu , Pt and Pd. At least one of the first non-magnetic layer 15 and the second magnetic layer 12 may contain an alloy containing any of them. At least one of the first non-magnetic layer 15 and the second magnetic layer 16 may include a laminated film containing at least two of those films.

The magnetic recording medium 80 includes, for example, a CoCrPt—SiO ₂ granular film.

12 (a) to 12 (c) are schematic cross-sectional views illustrating another magnetic recording head and another magnetic recording / reproducing device according to the first embodiment.
12 (b) and 12 (c) illustrate the state (operation) of the magnetic recording head and the magnetic recording / reproducing device.

As shown in FIG. 12A, the magnetic recording / reproducing device 150a according to the present embodiment includes the magnetic recording head 110a according to the present embodiment and the magnetic recording medium 80. In the present embodiment, the stacking direction of the first magnetic layer 11 and the second magnetic layer 12 is inclined with respect to the medium facing surface 51. Other than this, it is the same as the magnetic recording head 110.

Also in the magnetic recording head 110a and the magnetic recording / reproducing device 150a, the second product of the second thickness t2 and the second saturated magnetic flux density is larger than the first product of the first thickness t1 and the first saturated magnetic flux density. .. For example, the first thickness t1 is thinner than the second thickness t2.

Then, as shown in FIGS. 12 (b) and 12 (c), a current (first current Jc1) flows from the second magnetic layer 12 toward the first magnetic layer 11. The magnetic recording head 110a and the magnetic recording / reproducing device 150a can also provide a magnetic recording head and a magnetic recording / reproducing device capable of improving the recording density.

(Second embodiment)
13 (a) to 13 (c) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device according to the second embodiment.
13 (b) and 13 (c) illustrate the state (operation) of the magnetic recording head and the magnetic recording / reproducing device.

As shown in FIG. 13A, the magnetic recording / reproducing device 151 according to the present embodiment includes the magnetic recording head 111 according to the present embodiment and the magnetic recording medium 80. In the present embodiment, the arrangement of the first magnetic layer 11 and the second magnetic layer 12 is different from the arrangement in the magnetic recording head 110. In the following description of the magnetic recording head 111, the same parts as the magnetic recording head 110 may be omitted as appropriate.

The magnetic recording head 111 includes a magnetic pole 20, a shield 20s, a laminate 10, and a first non-magnetic layer 15. The shield 20s is, for example, a trailing shield. The laminate 10 includes a first magnetic layer 11, a second magnetic layer 12, and an intermediate layer 13. The first magnetic layer 11 is provided between the magnetic pole 20 and the shield 20s. The second magnetic layer 12 is provided between the first magnetic layer 11 and the shield 20s. The intermediate layer 13 is provided between the first magnetic layer 11 and the second magnetic layer 12 and is non-magnetic.

The first non-magnetic layer 15 is provided between the second magnetic layer 12 and the shield 20s. The first non-magnetic layer 15 is in contact with the shield 20s and the second magnetic layer 12.

The second non-magnetic layer 16 is provided between the first magnetic layer 11 and the magnetic pole 20.

The direction from the second magnetic layer 12 to the first magnetic layer 11 is defined as the first direction D1. The first direction D1 is opposite to the X direction. The direction from the first magnetic layer 11 to the second magnetic layer 12 is defined as the second direction D2. The second direction D2 is the same as the X direction.

Also in this example, the first magnetic layer 11 has a first thickness t1 along the first direction D1 and a first saturation magnetic flux density Bs1. The second magnetic layer 12 has a second thickness t2 along the first direction D1 and a second saturation magnetic flux density Bs2. Also in this example, the second product of the second thickness t2 and the second saturation magnetic flux density Bs2 is larger than the first product of the first thickness t1 and the first saturation magnetic flux density Bs1.

FIG. 13B corresponds to the first operation OP1 (first state). In the first state, the first magnetic field magnetic field Hg1 generated from the magnetic pole 20 has a component along the second direction D2. At this time, the first current Jc1 in the first direction D1 flows through the laminated body 10. At this time, the direction of the first electron flow Je1 is opposite to the direction of the first current Jc1.

FIG. 13C corresponds to the second operation OP2 (second state). In the second state, the second magnetic field magnetic field Hg2 generated from the magnetic pole 20 has a component along the first direction D1. Also at this time, the first current Jc1 in the first direction D1 flows through the laminated body 10.

By such an operation, a good high frequency magnetic field Hac can be obtained even if the first magnetic layer 11 is thinned. This makes it possible to provide a magnetic recording head and a magnetic recording / reproducing device capable of improving the recording density.

In the present embodiment, the second product is preferably four times or more the first product. The second thickness t2 is preferably at least twice the first thickness.

The first thickness t1 is preferably, for example, 2 nm or more and 9 nm or less. The vertical magnetic anisotropy magnetic field MA1 of the first magnetic layer 11 is preferably, for example, −7 kOe or more and 8 kOe or less.

In the present embodiment, the first magnetic layer 11 has a first damping constant α1. The second magnetic layer 12 has a second damping constant α2. At this time, the product of the second product and the second damping constant α2 is preferably 4 times or more and 16 times or less the product of the first product and the first damping constant α1.

In the present embodiment, in the first state, the magnetization 11 m of the first magnetic layer 11 has a component in the second direction D2. In the second state, the magnetization 11m of the first magnetic layer 11 has a component in the first direction D1.

In the first state and the second state, the laminated body 10 generates a high frequency magnetic field Hac. The frequency of the high frequency magnetic field Hac is 5 GHz or more and 25 GHz or less.

When a third magnetic field having a component in the first direction D1 is applied while passing a first current Jc1 through the laminated body 10, the electric resistance between the first magnetic layer 11 and the second magnetic layer 12 is the third magnetic field. Increases with the strength of.

The first magnetic layer 11 and the second magnetism when a third magnetic field having a size in the first range and having a component in the first direction D1 is applied while passing a third current in the first direction D1 through the laminated body 10. The electrical resistance between the layers 12 increases with the strength of the third magnetic field. The magnitude of the first current Jc1 is in such a first range.

In this embodiment, the coil 25 may be provided. In the first state, the first coil current C1 is supplied to the coil 25, and the first magnetic field magnetic field Hg1 is generated from the magnetic pole 20. In the second state, the second coil current C2 is supplied to the coil 25, and the second magnetic pole magnetic field Hg2 is generated from the magnetic pole 20.

In the present embodiment , the control unit 55 may be further provided. The control unit 55 supplies the first coil current C1 to the coil 25 in the first state, and supplies the first current Jc1 to the laminated body 10. The control unit 55 supplies the second coil current C 2 to the coil 25 in the second state, and supplies the first current Jc 1 to the laminated body 10.

(Third embodiment)
14 (a) to 14 (c) are schematic cross-sectional views illustrating the magnetic recording head and the magnetic recording / reproducing device according to the third embodiment.
As shown in FIG. 14A, the magnetic recording / reproducing device 152 according to the present embodiment includes the magnetic recording head 112 according to the present embodiment and the magnetic recording medium 80. In the present embodiment, the arrangement of the first magnetic layer 11 and the second magnetic layer 12 is different from the arrangement in the magnetic recording head 110. In the following description of the magnetic recording head 112, the same parts as the magnetic recording head 110 may be omitted as appropriate.

The magnetic recording head 112 includes a magnetic pole 20, a shield 20s, and a laminate 10. The shield 20s is, for example, a trailing shield. The laminated body 10 is provided between the magnetic pole 20 and the shield 20s. The laminate 10 includes a first magnetic layer 11, a second magnetic layer 12, and an intermediate layer 13. The first magnetic layer 11 is provided between the magnetic pole 20 and the shield 20s. The second magnetic layer 12 is separated from the first magnetic layer 11 in a direction intersecting the direction from the magnetic pole 20 toward the shield 20s (in this example, the Z direction). The intermediate layer 13 is provided between the first magnetic layer 11 and the second magnetic layer 12 and is non-magnetic.

The magnetic pole 20 has a medium facing surface 51. The distance between the medium facing surface 51 and the first magnetic layer 11 is longer than the distance between the medium facing surface 51 and the second magnetic layer 12. For example, the second magnetic layer 12 is located between the first magnetic layer 11 and the magnetic recording medium 80.

The direction from the second magnetic layer 12 to the first magnetic layer 11 is defined as the first direction D1. The first direction D1 corresponds to the Z direction. The direction from the first magnetic layer 11 to the second magnetic layer 12 is defined as the second direction D2. The second direction D2 is opposite (antiparallel) to the Z direction.

Also in this example, the first magnetic layer 11 has a first thickness t1 along the first direction D1 and a first saturation magnetic flux density Bs1. The second magnetic layer 12 has a second thickness t2 along the first direction D1 and a second saturation magnetic flux density Bs2. Also in this example, the second product of the second thickness t2 and the second saturation magnetic flux density Bs2 is larger than the first product of the first thickness t1 and the first saturation magnetic flux density Bs1.

In this example, the first insulating layer 17 and the second insulating layer 18 are further provided. The first insulating layer 17 is provided between the magnetic pole 20 and the laminated body 10. The second insulating layer 18 is provided between the shield 20s and the laminated body 10.

Also in this example, a current (first current Jc1) flows from the second magnetic layer 12 toward the first magnetic layer 11.

FIG. 14B corresponds to the first operation OP1 (first state). In the first state, the first magnetic field magnetic field Hg1 generated from the magnetic pole 20 has a component along the direction (+ X direction) from the magnetic pole 20 toward the shield 20s. A first current Jc1 in the first direction D1 flows through the laminated body 10. At this time, the direction of the first electron flow Je1 is opposite to the direction of the first current Jc1.

FIG. 14C corresponds to the second operation OP2 (second state). In the second state, the second magnetic field magnetic field Hg2 generated from the magnetic pole 20 has a component along the direction (−X direction) from the shield 20s toward the magnetic pole 20. Also at this time, the first current Jc1 in the first direction D1 flows through the laminated body 10.

By such an operation, a good high frequency magnetic field Hac can be obtained even if the first magnetic layer 11 is thinned. This makes it possible to provide a magnetic recording head and a magnetic recording / reproducing device capable of improving the recording density.

In the present embodiment, the second product is preferably four times or more the first product. The second thickness t2 is preferably at least twice the first thickness.

For example, the first thickness t1 is preferably, for example, 2 nm or more and 9 nm or less. The vertical magnetic anisotropy magnetic field MA1 of the first magnetic layer 11 is preferably, for example, −7 kOe or more and 8 kOe or less.

In the present embodiment, the first magnetic layer 11 has a first damping constant α1. The second magnetic layer 12 has a second damping constant α2. At this time, the product of the second product and the second damping constant α2 is preferably 4 times or more and 16 times or less the product of the first product and the first damping constant α1.

In the present embodiment, in the first state, the first magnetic layer 11 has a magnetization of 11 m . In the second state, the first magnetic layer 11 has a magnetization of 11 m .

In the first state and the second state, the laminated body 10 generates a high frequency magnetic field Hac. The frequency of the high frequency magnetic field Hac is 5 GHz or more and 25 GHz or less.

When a third magnetic field having a component in the X direction is applied to the laminated body 10 while passing a first current Jc1, the electric resistance between the first magnetic layer 11 and the second magnetic layer 12 is the strength of the third magnetic field. Ascends with.

In this embodiment, the coil 25 may be provided. In the first state, the first coil current C1 is supplied to the coil 25, and the first magnetic field magnetic field Hg1 is generated from the magnetic pole 20. In the second state, the second coil current C2 is supplied to the coil 25, and the second magnetic field magnetic field Hg2 is generated from the magnetic pole 20.

In the present embodiment , the control unit 55 may be further provided. The control unit 55 supplies the first coil current C1 to the coil 25 in the first state, and supplies the first current Jc1 to the laminated body 10. The control unit 55 supplies the second coil current C 2 to the coil 25 in the second state, and supplies the first current Jc 1 to the laminated body 10.

(Fourth Embodiment)
A fourth embodiment relates to a magnetic storage device. The magnetic storage device according to the present embodiment includes any one of the first to third embodiments, a magnetic recording head of a modification thereof, and a magnetic recording medium 80. Information is recorded on the magnetic recording medium 80 by the magnetic pole 20. A control unit 55 may be further provided.

The control unit 55 carries out the first operation OP1 and the second operation OP2. In the first operation OP1 and the second operation OP2, the control unit 55 supplies the first current Jc1 to the laminated body 10.

In this embodiment, the magnetic recording head further includes a coil 25. In the first operation OP1, the control unit 55 supplies the first coil current C1 to the coil 25 to generate the first magnetic field magnetic field Hg1 from the magnetic pole 20. In the second operation OP2, the control unit 55 supplies the second coil current C2 to the coil 25 to generate the second magnetic field magnetic field Hg2 from the magnetic pole 20.

Hereinafter, a case where the magnetic recording head 110 is used will be described.
FIG. 15 is a schematic perspective view illustrating a part of the magnetic recording / reproducing device according to the fourth embodiment.
FIG. 15 illustrates a head slider on which a magnetic recording head is mounted.
The magnetic recording head 110 is mounted on the head slider 3. For the head slider 3, for example, Al ₂ O ₃ / TiC or the like is used. The head slider 3 moves relative to the magnetic recording medium 80 while floating or contacting the magnetic recording medium 80.

The head slider 3 has, for example, an air inflow side 3A and an air outflow side 3B. The magnetic recording head 110 is arranged on the side surface of the air outflow side 3B of the head slider 3. As a result, the magnetic recording head 110 mounted on the head slider 3 moves relative to the magnetic recording medium 80 while floating or contacting the magnetic recording medium 80.

FIG. 16 is a schematic perspective view illustrating the magnetic recording / reproducing device according to the embodiment.
17 (a) and 17 (b) are schematic perspective views illustrating a part of a magnetic recording / reproducing device.
As shown in FIG. 16, the magnetic recording / reproducing device 150 according to the embodiment is a device of the type using a rotary actuator. The recording medium disk 180 is mounted on the spindle motor 4 and is rotated in the direction of arrow A by a motor that responds to a control signal from the drive device control unit. The magnetic recording / reproducing device 150 according to the present embodiment may include a plurality of recording medium discs 180. The magnetic recording / reproducing device 150 may include a recording medium 181. For example, the magnetic recording / playback device 150 is a hybrid HDD (Hard Disk Drive). The recording medium 181 is, for example, an SSD (Solid State Drive). As the recording medium 181, for example, a non-volatile memory such as a flash memory is used.

The head slider 3 for recording and reproducing the information stored in the recording medium disk 180 has the configuration as described above, and is attached to the tip of the thin film suspension 154. Here, for example, one of the magnetic recording heads according to the embodiment described above is mounted near the tip of the head slider 3.

When the recording medium disk 180 rotates, the pressing pressure by the suspension 154 and the pressure generated on the medium facing surface (ABS) of the head slider 3 are balanced, and the medium facing surface of the head slider 3 is from the surface of the recording medium disk 180. It is held with a predetermined levitation amount. It should be noted that the so-called "contact traveling type" in which the head slider 3 comes into contact with the recording medium disk 180 may be used.

The suspension 154 is connected to one end of an arm 155 (eg, an actuator arm). The arm 155 has, for example, a bobbin portion for holding a drive coil. A voice coil motor 156, which is a kind of linear motor, is provided at the other end of the arm 155. The voice coil motor 156 can include a drive coil wound around the bobbin portion of the arm 155, and a magnetic circuit including permanent magnets and facing yokes arranged so as to sandwich the coil. The suspension 154 has one end and the other end, a magnetic recording head is mounted on one end of the suspension 154, and an arm 155 is connected to the other end of the suspension 154.

The arm 155 is held by ball bearings provided at two places above and below the bearing portion 157, and can be freely rotated and slid by a voice coil motor 156. As a result, the magnetic recording head can be moved to an arbitrary position on the recording medium disk 180.

FIG. 17A illustrates a partial configuration of the magnetic recording / playback device and is an enlarged perspective view of the head stack assembly 160.
Further, FIG. 17B is a perspective view illustrating a magnetic recording head assembly (head gimbal assembly: HGA) 158 that is a part of the head stack assembly 160.

As shown in FIG. 17 (a), the head stack assembly 160 includes a bearing portion 157, a head gimbal assembly 158, and a support frame 161. The head gimbal assembly 158 extends from the bearing portion 157. The support frame 161 extends from the bearing portion 157 in the direction opposite to the HGA. The support frame 161 supports the coil 162 of the voice coil motor.

Further, as shown in FIG. 17B, the head gimbal assembly 158 has an arm 155 extending from the bearing portion 157 and a suspension 154 extending from the arm 155.

A head slider 3 is attached to the tip of the suspension 154. Then, one of the magnetic recording heads according to the embodiment is mounted on the head slider 3.

That is, the magnetic recording head assembly (head gimbal assembly) 158 according to the embodiment includes the magnetic recording head according to the embodiment, the head slider 3 on which the magnetic recording head is mounted, and the suspension 154 on which the head slider 3 is mounted at one end. , An arm 155 connected to the other end of the suspension 154.

The suspension 154 has lead wires (not shown) for recording and reproducing signals, for heaters for adjusting the amount of levitation, and for, for example, for spin torque oscillators. These lead wires and each electrode of the magnetic recording head incorporated in the head slider 3 are electrically connected.

Further, a signal processing unit 190 is provided which records and reproduces a signal on a magnetic recording medium using a magnetic recording head. The signal processing unit 190 is provided, for example, in a part of the magnetic recording / reproducing device 150 (see FIG. 16). The input / output lines of the signal processing unit 190 are connected to the electrode pads of the head gimbal assembly 158 and are electrically coupled to the magnetic recording head.

As described above, in the magnetic recording / reproducing device 150 according to the present embodiment, the magnetic recording medium, the magnetic recording head according to the above embodiment, and the magnetic recording medium and the magnetic recording head are separated or brought into contact with each other. A movable part that is relatively movable, a position control unit that aligns the magnetic recording head with a predetermined recording position on the magnetic recording medium, and a magnetic recording head are used to record and reproduce signals on the magnetic recording medium. It is provided with a signal processing unit.

That is, the recording medium disk 180 is used as the magnetic recording medium.
The movable portion can include the head slider 3.
Further, the position control unit may include a head gimbal assembly 158.

As described above, the magnetic recording / reproducing device 150 according to the present embodiment uses the magnetic recording medium, the magnetic recording head assembly according to the embodiment, and the magnetic recording head mounted on the magnetic recording head assembly to the magnetic recording medium. A signal processing unit for recording and reproducing a signal is provided.

According to the embodiment, a magnetic recording head and a magnetic recording / reproducing device capable of improving the recording density are provided.

In the specification of the present application, "vertical" and "parallel" include not only strict vertical and strict parallel, but also variations in the manufacturing process, for example, and may be substantially vertical and substantially parallel. It's fine.

Hereinafter, embodiments of the present invention have been described with reference to specific examples. However, the embodiments of the present invention are not limited to these specific examples. For example, specific configurations of each element such as a shield, a magnetic pole, an intermediate layer and an insulating portion included in a magnetic recording head, and a magnetic recording medium included in a magnetic recording / reproducing device are appropriately configured from a range known to those skilled in the art. The present invention is included in the scope of the present invention as long as the present invention can be carried out in the same manner and the same effect can be obtained by selecting.

Further, a combination of any two or more elements of each specific example to the extent technically possible is also included in the scope of the present invention as long as the gist of the present invention is included.

In addition, all magnetic recording / reproducing devices that can be appropriately designed and reproduced by those skilled in the art based on the above-mentioned magnetic recording / reproducing device as an embodiment of the present invention are also included in the present invention as long as the gist of the present invention is included. It belongs to the range of.

In addition, in the scope of the idea of the present invention, those skilled in the art can come up with various modified examples and modified examples, and it is understood that these modified examples and modified examples also belong to the scope of the present invention. ..

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

3 ... Head slider, 3A ... Air inflow side, 3B ... Air outflow side, 4 ... Spindle motor, 10 ... Laminate, 11 ... First magnetic layer, 11m ... Magnetization, 12 ... Second magnetic layer, 12m ... Magnetization, 13 ... intermediate layer, 15 ... first non-magnetic layer, 16 ... second non-magnetic layer, 17 ... first insulating layer, 18 ... second insulating layer, 20 ... magnetic pole, 20s ... shield, 25 ... coil, 51 ... medium facing Surface, 55 ... Control unit, 80 ... Magnetic recording medium, 84 ... Magnetization, 85 ... Medium movement direction, 110, 110a, 111, 112, 119x-119y ... Magnetic recording head, 150, 150a, 151, 152, ... Magnetic recording Reproduction device, 154 ... Suspension, 155 ... Actuator arm, 156 ... Voice coil motor, 157 ... Bearing part, 158 ... Head gimbal assembly, 160 ... Head stack assembly, 161 ... Support frame, 162 ... Coil, 180 ... Recording medium disk , 181 ... Recording medium, 190 ... Signal processing unit, A ... Arrow, C1, C2 ... 1st and 2nd coil currents, D1, D2 ... 1st and 2nd directions, Hac ... High frequency magnetic field, Hacn ... Strength, Hg1, Hg2 ... 1st and 2nd magnetic pole magnetic field, Hgap ... Gap magnetic field, Hr1, Hr2 ... 1st and 2nd recording magnetic field, J ... Current density, J80% ... 80% current density, Jc1, Jc2 ... 1st and 2nd current , Je1, Je2 ... 1st, 2nd electron flow, Js ... Oscillation start current density, M1 ... Direction, MA1 ... Vertical magnetic anisotropic magnetic field, OP1, OP2 ... 1st, 2nd operation, R1 ... Resistance, R2 / 1 ... Ratio, Rt ... Ratio, RtBs ... Ratio, f1 ... Frequency, g20 ... Gap length, t1 to t3 ... 1st to 3rd thickness

Claims (9)

With magnetic poles
It ’s a laminated body,
The first magnetic layer of the in-plane magnetization film and
A second magnetic layer provided between the first magnetic layer and the magnetic pole,
A non-magnetic intermediate layer provided between the first magnetic layer and the second magnetic layer,
With the above-mentioned laminated body including
A first non-magnetic layer provided between the second magnetic layer and the magnetic pole and in contact with the magnetic pole and the second magnetic layer,
Equipped with
The first magnetic layer has a first thickness along a first direction from the second magnetic layer toward the first magnetic layer, and a first saturation magnetic flux density.
The second magnetic layer has a second thickness along the first direction and a second saturation magnetic flux density.
The second product of the second thickness and the second saturated magnetic flux density is larger than the first product of the first thickness and the first saturated magnetic flux density.
The product of the damping constant of the second magnetic layer and the second product is 4 times or more and 16 times or less the product of the damping constant of the first magnetic layer and the first product.
A current flows from the second magnetic layer toward the first magnetic layer.
Magnetic recording head. The magnetic head according to claim 1, wherein the direction of magnetization of the first magnetic layer changes depending on the magnitude of the current. The magnetic head according to claim 1 or 2, wherein the second product of the second thickness and the second saturated magnetic flux density is four times or more the first product of the first thickness and the first saturated magnetic flux density. .. Claims 1 to 3 that the electric resistance between the first magnetic layer and the second magnetic layer when the current is passed through the laminated body increases with the strength of the magnetic field having the component in the first direction. The magnetic recording head according to any one of. In the first state, a first magnetic field having a component along the first direction is generated from the magnetic pole.
In the second state, a second magnetic field having a component along the second direction from the first magnetic layer toward the second magnetic layer is generated from the magnetic pole.
The magnetic recording head according to claim 2 , wherein in the first state, the magnetization of the first magnetic layer has a component in the second direction. The magnetic recording head according to claim 5 , wherein in the second state, the magnetization of the first magnetic layer has a component in the first direction. With more trailing shields
The magnetic recording head according to any one of claims 1 to 6 , wherein the laminated body is located between the magnetic pole and the trailing shield. The magnetic recording head according to any one of claims 1 to 7 .
A magnetic recording medium on which information is recorded by the magnetic poles and
A control unit that allows the current to flow through the laminate,
A magnetic recording / playback device equipped with. The magnetic recording head according to claim 5 or 6 ,
A magnetic recording medium on which information is recorded by the magnetic poles and
A control unit that allows the current to flow through the laminate,
Equipped with
The magnetic recording head further includes a coil.
In the first operation, the control unit supplies the first coil current to the coil to generate the first magnetic field having a component along the first direction in the magnetic pole.
In the second operation, the control unit supplies a second coil current to the coil and has a component in the magnetic pole along the second direction from the first magnetic layer to the second magnetic layer. A magnetic recording / playback device that generates.

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