Magnetic head and magnetic recording device

Abstract

To provide a magnetic head and a magnetic recording device capable of improving characteristics.SOLUTION: According to the embodiment, a magnetic head includes a reproducing section including a medium-facing surface. The reproducing section includes first to fourth shields, a first magnetic element, first and second non-magnetic layers, and first to third terminals. The first magnetic element is provided between the first and second shields and between the third and fourth shields. The first non-magnetic layer is provided between the first shield and the first magnetic element. The second non-magnetic layer is provided between the first magnetic element and the second shield. The first non-magnetic layer includes a first surface facing the first shield. The second non-magnetic layer includes a second surface facing the second shield. A first ratio of the second length in a second direction of the first magnetic element to the first distance in the first direction between the first and second surfaces is 0.6 or greater.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a magnetic head and a magnetic recording device. [Background technology]

[0002] A magnetic head including a magnetic sensor is used to reproduce information recorded on a magnetic recording medium such as an HDD (Hard Disk Drive), and improvements in the characteristics of the magnetic head are desired. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 7,576,948 Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments of the present invention provide a magnetic head and a magnetic recording device that can improve characteristics. [Means for solving the problem]

[0005] According to an embodiment, a magnetic head includes a reproducing section including a medium facing surface. The reproducing section includes a first shield, a second shield, a third shield, a fourth shield, a first magnetic element, a first non-magnetic layer, a second non-magnetic layer, a first terminal, a second terminal, and a third terminal. A direction from the first shield to the second shield is along a first direction along the medium facing surface. A second direction from the third shield to the fourth shield is along the medium facing surface and intersects the first direction. The first magnetic element is provided between the first shield and the second shield and between the third shield and the fourth shield. The first non-magnetic layer is provided between the first shield and the first magnetic element. The second non-magnetic layer is provided between the first magnetic element and the second shield. The first terminal is electrically connected to the first shield. The second terminal is electrically connected to the second shield. The third terminal is electrically connected to the first magnetic element. The first nonmagnetic layer includes a first surface facing the first shield, the second nonmagnetic layer includes a second surface facing the second shield, and a first ratio of a second length of the first magnetic element in the second direction to a first distance in the first direction between the first surface and the second surface is 0.6 or greater. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic plan view illustrating the magnetic head according to the first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view illustrating the magnetic head according to the first embodiment. [Figure 3] FIG. 3 is a graph illustrating the characteristics of the magnetic head. [Figure 4] FIG. 4 is a graph illustrating the characteristics of the magnetic head. [Figure 5] FIG. 5 is a graph illustrating the characteristics of the magnetic head. [Figure 6] FIG. 6 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. [Figure 7] FIG. 7 is a graph illustrating the characteristics of the magnetic head. [Figure 8] FIG. 8 is a schematic plan view illustrating the magnetic head according to the first embodiment. [Figure 9] 9A and 9B are schematic views illustrating the magnetic head according to the first embodiment. [Figure 10] 10A and 10B are schematic views illustrating the magnetic head according to the first embodiment. [Figure 11] FIG. 11 is a schematic plan view illustrating the magnetic head according to the first embodiment. [Figure 12] FIG. 12 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. [Figure 13] FIG. 13 is a schematic plan view illustrating the magnetic head according to the first embodiment. [Figure 14] FIG. 14 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. [Figure 15] FIG. 15 is a schematic plan view illustrating the magnetic head according to the first embodiment. [Figure 16] FIG. 16 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. [Figure 17] FIG. 17 is a schematic plan view illustrating the magnetic head according to the first embodiment. [Figure 18] FIG. 18 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. [Figure 19] FIG. 19 is a schematic view illustrating the magnetic head according to the first embodiment. [Figure 20] FIG. 20 is a schematic view illustrating the magnetic head according to the first embodiment. [Figure 21] 21A and 21B are schematic views illustrating the magnetic head according to the first embodiment. [Figure 22] FIG. 22 is a schematic view illustrating the magnetic head according to the first embodiment. [Figure 23] FIG. 23 is a schematic view illustrating the magnetic head according to the first embodiment. [Figure 24]24(a) and 24(b) are schematic views illustrating the magnetic head according to the first embodiment. [Figure 25] FIG. 25 is a schematic perspective view illustrating the magnetic head according to the first embodiment. [Figure 26] FIG. 26 is a schematic view illustrating the magnetic recording device according to the embodiment. [Figure 27] FIG. 27 is a schematic perspective view illustrating the magnetic head according to the embodiment. [Figure 28] FIG. 28 is a schematic perspective view illustrating a part of the magnetic recording device according to the embodiment. [Figure 29] FIG. 29 is a schematic perspective view illustrating the magnetic recording device according to the embodiment. [Figure 30] 30A and 30B are schematic perspective views illustrating a part of the magnetic recording device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] 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 size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In this specification and in each drawing, elements similar to those previously described with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0008] (First embodiment) FIG. 1 is a schematic plan view illustrating the magnetic head according to the first embodiment. FIG. 2 is a schematic cross-sectional view illustrating the magnetic head according to the first embodiment. FIG. 2 is a cross-sectional view taken along line X1-X2 of FIG. As shown in Fig. 1, the magnetic head 110 according to the embodiment includes a reproducing section 70. As shown in Fig. 2, the reproducing section 70 includes a medium facing surface 10F.

[0009] As shown in FIG. 2, the medium facing surface 10F faces the magnetic recording medium 80. The magnetic recording device 210 according to the embodiment includes a magnetic head 110 and a magnetic recording medium 80. As will be described later, the magnetic head 110 may further include a recording unit. The recording unit records information on the magnetic recording medium 80. The recording unit controls the magnetization of the magnetic recording medium 80 in accordance with the information. For example, the reproducing unit 70 detects the magnetization of the magnetic recording medium 80. The reproducing unit 70 reproduces the information recorded on the magnetic recording medium 80.

[0010] The direction perpendicular to the magnetic recording medium 80 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 the Z-axis direction and the X-axis direction is defined as the Y-axis direction. The Z-axis direction is, for example, the height direction. The X-axis direction may be, for example, the down-track direction. The Y-axis direction may be, for example, the cross-track direction. The medium facing surface 10F is, for example, along the XY plane. Figure 1 corresponds to a plan view of the reproducing section 70 as seen from the medium facing surface 10F.

[0011] As shown in FIG. 1, the reproducing section 70 includes a first shield 41, a second shield 42, a third shield 43, a fourth shield 44, a first magnetic element 11, a first non-magnetic layer 31, a second non-magnetic layer 32, a first terminal 41T, a second terminal 42T, and a third terminal 43T.

[0012] The direction from the first shield 41 to the second shield 42 is along the first direction D1. The first direction D1 is along the medium facing surface 10F. The first direction D1 may be, for example, the X-axis direction.

[0013] A second direction D2 from the third shield 43 to the fourth shield 44 runs along the medium facing surface 10F and intersects with the first direction D1. The second direction D2 may be, for example, the Y-axis direction.

[0014] The first magnetic element 11 is provided between the first shield 41 and the second shield 42 and between the third shield 43 and the fourth shield 44.

[0015] The first non-magnetic layer 31 is provided between the first shield 41 and the first magnetic element 11. The second non-magnetic layer 32 is provided between the first magnetic element 11 and the second shield 42. For example, the first non-magnetic layer 31 contacts the first magnetic element 11. The second non-magnetic layer 32 contacts the first magnetic element 11. For example, the first non-magnetic layer 31 is electrically connected to the first shield 41 and the first magnetic element 11. The second non-magnetic layer 32 is electrically connected to the first magnetic element 11 and the second shield 42. For example, the first shield 41 and the first magnetic element 11 may be electrically connected by a tunnel junction via the first non-magnetic layer 31. For example, the second shield 42 and the first magnetic element 11 may be electrically connected by a tunnel junction via the second non-magnetic layer 32.

[0016] The first terminal 41T is electrically connected to the first shield 41. The second terminal 42T is electrically connected to the second shield 42. The third terminal 43T is electrically connected to the first magnetic element 11. For example, the first terminal 41T is electrically connected to the first magnetic element 11 via the first non-magnetic layer 31. For example, the second terminal 42T is electrically connected to the first magnetic element 11 via the second non-magnetic layer 32. For example, the first terminal 41T may be electrically connected to the first magnetic element 11 via a tunnel junction. For example, the second terminal 42T may be electrically connected to the first magnetic element 11 via a tunnel junction.

[0017] In this example, the reproducing section 70 further includes a third non-magnetic layer 33. The third non-magnetic layer 33 is provided between the third shield 43 and the first magnetic element 11. The third non-magnetic layer 33 is electrically connected to the third shield 43 and the first magnetic element 11. The third terminal 43T is electrically connected to the third shield 43.

[0018] The first shield 41 is, for example, one of a trailing shield and a leading shield. The second shield 42 is, for example, the other of a trailing shield and a leading shield. The third shield 43 and the fourth shield 44 are, for example, side shields.

[0019] In the embodiment, a signal corresponding to the information recorded on the magnetic recording medium 80 is obtained from the reproducing unit 70. For example, the voltage (detection signal) between one of the first terminal 41T and the second terminal 42T and the third terminal 43T changes according to the information recorded on the magnetic recording medium 80.

[0020] For example, the magnetization of the first magnetic element 11 changes in accordance with the information (magnetization) recorded on the magnetic recording medium 80. The detection signal obtained from the reproducing unit 70 corresponds to the change in the magnetization of the first magnetic element 11. For example, the direction intersecting the medium facing surface 10F is defined as a third direction D3. The third direction D3 is, for example, the Z-axis direction. For example, the component of the magnetization of the first magnetic element 11 along the third direction D3 changes in accordance with the information (magnetization) recorded on the magnetic recording medium 80.

[0021] Meanwhile, for example, a magnetic action occurs between the first shield 41 and the first magnetic element 11. For example, the angle between the magnetization of the first shield 41 at a portion facing the first magnetic element 11 and the magnetization of the first magnetic element 11 changes according to the information (magnetization) recorded on the magnetic recording medium 80. The detection signal obtained from the reproducing unit 70 is based on such a change in angle.

[0022] For example, a magnetic interaction occurs between the second shield 42 and the first magnetic element 11. For example, the angle between the magnetization of the portion of the second shield 42 facing the first magnetic element 11 and the magnetization of the first magnetic element 11 changes according to the information (magnetization) recorded on the magnetic recording medium 80. The detection signal obtained from the reproducing unit 70 is based on such a change in angle.

[0023] For example, a signal based on the magnetic interaction between the first shield 41 and the first magnetic element 11 is used for reproduction. Alternatively, a signal based on the magnetic interaction between the second shield 42 and the first magnetic element 11 is used for reproduction. These signals obtained from the reproducing unit 70 change depending on the information (magnetization) of the magnetic recording medium 80.

[0024] As will be described later, it has been found that the ability of signals obtained from the reproducing unit 70 to follow the magnetization of the magnetic recording medium 80 changes depending on the structure of the reproducing unit 70. As will be described later, by optimizing the structure of the reproducing unit 70, good followability can be obtained for these signals (reproduced signals) obtained from the reproducing unit 70.

[0025] As shown in FIG. 1, the first non-magnetic layer 31 includes a first surface 31F facing the first shield 41. The second non-magnetic layer 32 includes a second surface 32F facing the second shield 42. The distance between the first surface 31F and the second surface 32F in the first direction D1 is defined as a first distance LN1. The length of the first magnetic element 11 in the second direction D2 is defined as a second length LN2. A first ratio of the second length LN2 to the first distance LN1 is 0.6 or greater. This allows for good tracking of the reproduced signal. A magnetic head with improved characteristics can be provided.

[0026] 3 and 4 are graphs illustrating the characteristics of the magnetic head. These figures illustrate simulation results of the change in magnetization of the first magnetic element 11 over time. FIG. 3 corresponds to the first configuration CF1. In the first configuration CF1, the first ratio is 1. FIG. 4 corresponds to the second configuration CF2. In the second configuration CF2, the first ratio is 0.5. The horizontal axis of these figures is time tm. The vertical axis of FIGS. 3 and 4 is the direction (normalized value) of the magnetization M. These figures illustrate the magnetic field H1 (normalized value) applied from the magnetic recording medium 80 to the first magnetic element 11, and the magnetization Mz (normalized value) of the first magnetic element 11.

[0027] 3, in the first configuration CF1, the magnetization Mz of the first magnetic element 11 changes in response to changes in the magnetic field H1 applied from the magnetic recording medium 80. The degree of oscillation is low in the magnetization Mz. The magnetization Mz has good tracking ability with respect to the magnetic field H1 from the medium.

[0028] As shown in FIG. 4, in the second configuration CF2, the magnetization Mz of the first magnetic element 11 oscillates greatly, and the response to changes in the magnetic field H1 applied from the magnetic recording medium 80 is poor.

[0029] In this way, the change in magnetization of the first magnetic element 11 varies depending on the first ratio for the reproducing section .

[0030] FIG. 5 is a graph illustrating the characteristics of the magnetic head. The horizontal axis of FIG. 5 represents the first ratio R1. The vertical axis of FIG. 5 represents the parameter P1. The parameter P1 is the square of the difference between the magnetic field H1 (normalized value) applied to the first magnetic element 11 from the magnetic recording medium 80 and the magnetization Mz (normalized value) of the first magnetic element 11. When the parameter P1 is small, the magnetization Mz of the first magnetic element 11 changes while properly following the magnetic field H1 from the magnetic recording medium 80. In this example, the thickness of the first non-magnetic layer 31 is the same as the thickness of the second non-magnetic layer 32. In this example, the first distance LN1 is changed by changing the thicknesses of these layers. In this example, the second length LN2 is constant. In the example of FIG. 5, the third length LN3 (see FIG. 6) of the first magnetic element 11 in the third direction D3 is the same as the second length LN2.

[0031] As shown in FIG. 5, when the first ratio R1 is low, the parameter P1 is large. When the first ratio R1 is high, the parameter P1 is small. The change in the parameter P1 relative to the first ratio R1 changes critically at a specific value of the first ratio R1. In this example, the specific value of the first ratio R1 is approximately 0.5 to 0.6. Such characteristics also occur when the first ratio R1 changes as the second length LN2 changes while the first distance LN1 is constant.

[0032] For example, when the first ratio R1 is 0.6 or more, a small parameter P1 is obtained. When the first ratio R1 is 0.75 or more, an even smaller parameter P1 is obtained.

[0033] In the embodiment, the first ratio R1 is 0.6 or more. This results in a small parameter P1. This results in a reproduction signal that satisfactorily follows changes in the magnetic field from the magnetic recording medium 80. In the embodiment, the first ratio R1 may be 0.75 or more. A smaller parameter P1 can be stably obtained. According to the embodiment, a magnetic head with improved characteristics can be provided.

[0034] In the embodiment, the first ratio R1 may be 1.5 or less. For example, the second length LN2 is prevented from becoming excessively long. For example, high resolution is easily obtained in the cross-track direction. By setting the first ratio R1 to 1.5 or less, for example, the first distance LN1 is prevented from becoming excessively short. For example, noise caused by thermal fluctuation is suppressed.

[0035] The characteristics illustrated in FIGS. 3 to 5 are considered to be related to the action of spin torque in a stack including the first non-magnetic layer 31, the first magnetic element 11, and the second non-magnetic layer 32. For example, spin torque oscillation is considered to occur in the stack. For example, spin torque is generated based on a current flowing through the stack. Spin torque occurs at the interface between the first non-magnetic layer 31 and the first magnetic element 11 and at the interface between the first magnetic element 11 and the second non-magnetic layer 32. Furthermore, spin is reflected at the first surface 31F of the first non-magnetic layer 31 and the second surface 32F of the second non-magnetic layer 32. The spin torque changes depending on the thickness of the first non-magnetic layer 31 and the thickness of the second non-magnetic layer 32. The characteristics related to spin torque are considered to be related to the distance (first distance LN1) between the first surface 31F and the second surface 32F.

[0036] For example, when the distance between the first surface 31F and the second surface 32F (first distance LN1) is relatively short with respect to the width of the first magnetic element 11 (second length LN2), the influence of the spin torque is considered to be suppressed.

[0037] In the embodiment, the direction of the spin torque acting on the first magnetic element 11 from the interface between the first non-magnetic layer 31 and the first magnetic element 11 is the same as the direction of the spin torque acting on the first magnetic element 11 from the interface between the second non-magnetic layer 32 and the first magnetic element 11. In this configuration, the effect of the spin torque has a large effect on the reproduction signal. By optimizing the first ratio R1, a reproduction signal with good tracking performance can be obtained.

[0038] In one reference example, a TMR element with a two-terminal structure is used as the reproducing section 70. In this reference example, the spin torques acting on the magnetic element (generally called the free layer) from the two interfaces described above are in opposite directions. The spin torques act to cancel each other out. In a TMR element, the characteristics shown in FIG. 5 do not occur. The characteristics illustrated in FIGS. 3 to 5 are unique to the reproducing section 70, which is a three-terminal element.

[0039] In the embodiment, the first distance LN1 may be, for example, 4 nm or more and 20 nm or less, and the second length LN2 may be, for example, 6 nm or more and 35 nm or less.

[0040] The thickness of the first magnetic element 11 in the first direction D1 is preferably, for example, 1 nm or more. For example, noise due to thermal fluctuations can be suppressed. This thickness is more preferably 2 nm or more. This thickness may be 16 nm or less.

[0041] In the embodiment, for example, at least one of the first non-magnetic layer 31 and the second non-magnetic layer 32 includes at least one selected from the group consisting of Cu, Al, Au, Ag, W, Ta, Si, C, AlO, and MgO.

[0042] The third non-magnetic layer 33 includes at least one selected from the group consisting of Cu, Al, Au, and Ag. For example, good electrical resistance can be obtained. For example, a low-noise detection signal can be obtained.

[0043] At least one of the first shield 41, the second shield 42, the third shield 43, and the fourth shield 44 may include at least one selected from the group consisting of Fe and Co. These shields may include, for example, a soft magnetic material.

[0044] As shown in FIG. 1 , the reproducing unit 70 may include an insulating member 30i. At least a portion of the insulating member 30i is provided around the first magnetic element 11. A portion of the insulating member 30i may be provided between the third shield 43 and the first shield 41. A portion of the insulating member 30i may be provided between the third shield 43 and the second shield 42. A portion of the insulating member 30i may be provided between the fourth shield 44 and the first shield 41. A portion of the insulating member 30i may be provided between the fourth shield 44 and the second shield 42. The insulating member 30i may include, for example, at least one selected from the group consisting of Si and Al, and at least one selected from the group consisting of oxygen and nitrogen.

[0045] As already described, the magnetic recording device 210 according to the embodiment includes a magnetic head 110 and a magnetic recording medium 80. As shown in FIG. 1, the magnetic recording device 210 may include a first circuit 51 and a second circuit 52. The first circuit 51 is configured to supply a current between a first terminal 41T and a second terminal 42T. The second circuit 52 is configured to detect a voltage between a third terminal 43T and one of the first terminal 41T and the second terminal 42T. This voltage is configured to change depending on the magnetization state recorded on the magnetic recording medium 80. By detecting the voltage, information recorded on the magnetic recording medium 80 is reproduced.

[0046] FIG. 6 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. As shown in FIG. 6, in the magnetic head 110, the first magnetic element 11 has a third length LN3 in the third direction D3. As already explained, in the example of FIG. 5, the second length LN2 is the same as the third length LN3. In the embodiment, the ratio of the second length LN2 to the third length LN3 (the length of the first magnetic element 11 in the third direction D3) may be, for example, not less than 0.5 and not more than 2. In this case, a first ratio R1 of not less than 0.7 results in a small parameter P1.

[0047] As already explained, the relationship between the first ratio R1 and the parameter P1 is considered to be caused by the spin torque. The size of the first magnetic element 11 (for example, at least one of the second length LN2 and the third length LN3) is considered to be related to the parameter P1.

[0048] Here, the ratio of the 1 / 2 power of the product of the second length LN2 and the third length LN3 to the first distance LN1 is defined as a second ratio.

[0049] FIG. 7 is a graph illustrating the characteristics of the magnetic head. The horizontal axis of FIG. 7 is the second ratio R2. The vertical axis is the parameter P1. As shown in FIG. 7, when the second ratio R2 is 0.7 or more, a small parameter P1 is obtained. In an embodiment, the second ratio R2 may be 0.9 or more. A smaller parameter P1 is obtained.

[0050] FIG. 8 is a schematic plan view illustrating the magnetic head according to the first embodiment. 8, in the magnetic head 111 according to the embodiment, the magnetization directions are opposite in the first shield 41 and the second shield 42. Except for this, the configuration of the magnetic head 111 (magnetic recording device 211) may be the same as the configuration of the magnetic head 110 (and the magnetic recording device 210).

[0051] In the magnetic head 111, the first magnetization 41M of the first shield 41 includes a first component in a third direction D3 that intersects with the medium facing surface 10F. The second magnetization 42M of the second shield 42 includes a second component in a fourth direction D4 that is opposite to the third direction D3.

[0052] 8, the first shield 41 includes a first region r1 facing the first magnetic element 11. The second shield 42 includes a second region r2 facing the first magnetic element 11. The first region magnetization r1M of the first region r1 includes a component (first region component) along the third direction D3. The second region magnetization r2M of the second region r2 includes a component (second region component) along the fourth direction D4 opposite to the third direction D3.

[0053] A change in the angle between the first region magnetization r1M, which includes a component along the third direction D3, and the magnetization of the first magnetic element 11 changes the first electrical resistance between the first shield 41 and the first magnetic element 11. This is thought to be due to the magnetoresistance effect. A change in the angle between the second region magnetization r2M, which includes a component along the fourth direction D4, and the magnetization of the first magnetic element 11 changes the second electrical resistance between the second shield 42 and the first magnetic element 11. This is thought to be due to the magnetoresistance effect.

[0054] The component of the first region magnetization r1M along the third direction D3 and the component of the second region magnetization r2M along the third direction D3 are in opposite directions. Therefore, for example, when the magnetization direction of the first magnetic element 11 changes and the first electrical resistance increases, the second electrical resistance decreases. For example, when the first electrical resistance decreases, the second electrical resistance increases. By detecting such changes in electrical resistance, information recorded on the magnetic recording medium 80 can be reproduced with high sensitivity.

[0055] 9A and 9B are schematic views illustrating the magnetic head according to the first embodiment. Fig. 9(a) is a schematic plan view, and Fig. 9(b) illustrates a part of the cross section taken along line X1-X2 in Fig. 9(a). 9(a), in the magnetic head 112 according to the embodiment, the first magnetic element 11 includes a plurality of films. Except for this, the configuration of the magnetic head 112 (and the magnetic recording device 212) may be similar to the configuration of the magnetic head 110 (and the magnetic recording device 210).

[0056] In the magnetic head 112, the first magnetic element 11 includes a first magnetic film 11a, a second magnetic film 11b, and a first non-magnetic film 11c. The second magnetic film 11b is provided between the first magnetic film 11a and the second shield 42. The first non-magnetic film 11c is provided between the first magnetic film 11a and the second magnetic film 11b.

[0057] The first non-magnetic film 11c includes, for example, at least one selected from the group consisting of Cu, Ru, Ir, and Au. The first non-magnetic film 11c has a first non-magnetic film thickness t3 (see FIG. 9(b)) along the first direction D1 of 0.1 nm to 10 nm. For example, the second magnetic film 11b is antiferromagnetically coupled to the first magnetic film 11a.

[0058] 9(b), the first magnetic film 11a has a first magnetic film thickness t1 along the first direction D1. The second magnetic film 11b has a second magnetic film thickness t2 along the first direction D1. In the magnetic head 112, the first magnetic film thickness t1 is thinner than the second magnetic film thickness t2. With this configuration, information (magnetization) recorded on the magnetic recording medium 80 can be reproduced with low noise.

[0059] In the embodiment, the magnetization direction of the magnetic film included in the first magnetic element 11 changes in accordance with the information (magnetization) of the magnetic recording medium 80. For example, the second magnetic film 11b is antiferromagnetically coupled to the first magnetic film 11a. The magnetizations of these magnetic films tend to rotate in conjunction with each other. At this time, due to differences in the thicknesses of these magnetic films, the changes in the magnetization of these magnetic films in accordance with the information (magnetization) of the magnetic recording medium 80 differ from one another.

[0060] For example, the exchange magnetic field is large in the thin first magnetic film 11a. On the other hand, the exchange magnetic field is small in the thick second magnetic film 11b. A difference occurs between a first electrical resistance between the first magnetic film 11a and the first non-magnetic layer 31 and a second electrical resistance between the second magnetic film 11b and the second non-magnetic layer 32. By detecting the change in the difference in electrical resistance, the information (magnetization) of the magnetic recording medium 80 can be detected.

[0061] For example, the ratio of the absolute value of the difference between the first magnetic film thickness t1 and the second magnetic film thickness t2 to the first magnetic film thickness t1 may be 0.1 or more.

[0062] In the magnetic head 112, the two magnetic films may have different thicknesses and saturation magnetizations. For example, the first magnetic film 11a has a first magnetic film thickness t1 along the first direction D1 and a first saturation magnetization Ms1. The second magnetic film 11b has a second magnetic film thickness t2 along the first direction D1 and a second saturation magnetization Ms2. In the embodiment, the first product (Ms1·t1) of the first magnetic film thickness t1 and the first saturation magnetization Ms1 may be smaller than the second product (Ms2·t2) of the second magnetic film thickness t2 and the second saturation magnetization Ms2. This also enables highly accurate reproduction. For example, the influence of noise is suppressed. According to the embodiment, a magnetic head with improved characteristics can be provided.

[0063] For example, the ratio of the absolute value of the difference between the first product and the second product to the first product may be 0.1 or more.

[0064] As shown in FIG. 9(a), for example, the first magnetization 41M of the first shield 41 may be along the third direction D3. The second magnetization 42M of the second shield 42 may be along the third direction D3. For example, the first shield 41 includes a first region r1 facing the first magnetic element 11. The second shield 42 includes a second region r2 facing the first magnetic element 11. The first region magnetization r1M of the first region r1 includes a component (first region component) along the third direction D3. The second region magnetization r2M of the second region r2 includes a component (second region component) along the third direction D3. Both of these magnetizations may include a component along the fourth direction D4.

[0065] 10A and 10B are schematic views illustrating the magnetic head according to the first embodiment. Fig. 10(a) is a schematic plan view, and Fig. 10(b) illustrates a part of the cross section taken along line X1-X2 in Fig. 10(a). 10(a), in the magnetic head 113 according to the embodiment, the first magnetic element 11 includes a plurality of films. Except for this, the configuration of the magnetic head 113 (and the magnetic recording device 213) may be similar to the configuration of the magnetic head 110 (and the magnetic recording device 210).

[0066] In the magnetic head 113, the first magnetic element 11 includes a first magnetic film 11a, a second magnetic film 11b, and a first non-magnetic film 11c. The second magnetic film 11b is provided between the first magnetic film 11a and the second shield 42. The first non-magnetic film 11c is provided between the first magnetic film 11a and the second magnetic film 11b.

[0067] The first non-magnetic film 11c includes, for example, at least one selected from the group consisting of Cu, Ru, Ir, and Au. The first non-magnetic film 11c has a first non-magnetic film thickness t3 (see FIG. 9(b)) along the first direction D1 of 0.1 nm to 10 nm. For example, the second magnetic film 11b is antiferromagnetically coupled to the first magnetic film 11a.

[0068] 10(b), the first magnetic film thickness t1 is substantially the same as the second magnetic film thickness t2 in the magnetic head 113. With this configuration, the information (magnetization) recorded on the magnetic recording medium 80 can be reproduced with high accuracy.

[0069] In the magnetic head 113, the magnetization direction of the magnetic film included in the first magnetic element 11 changes in accordance with the information (magnetization) of the magnetic recording medium 80. For example, the second magnetic film 11b is antiferromagnetically coupled to the first magnetic film 11a. The magnetizations of these magnetic films tend to rotate in conjunction with each other. Furthermore, the magnetizations of these magnetic films tend to change in accordance with the information (magnetization) of the magnetic recording medium 80.

[0070] The first magnetic film 11a and the second magnetic film 11b are aligned along a first direction D1 (e.g., the down-track direction). These magnetic films are positioned at different spatial locations along the first direction D1. The potential of the first magnetic element 11 changes depending on the relationship between the spatial distribution of the magnetic field from the magnetic recording medium 80 along the first direction D1 and the spatial positional relationship of the first magnetic film 11a and the second magnetic film 11b along the first direction D1. In the first magnetic element 11, a difference occurs between a first electrical resistance between the first magnetic film 11a and the first shield 41 and a second electrical resistance between the second magnetic film 11b and the second shield 42. By detecting the change in the difference in electrical resistance, information (magnetization) on the magnetic recording medium 80 can be detected. For example, high-resolution reproduction corresponding to high-density storage is possible.

[0071] In the magnetic head 113, the ratio of the absolute value of the difference between the first magnetic film thickness t1 and the second magnetic film thickness t2 to the first magnetic film thickness t1 may be 0.1 or less.

[0072] In the magnetic head 113, the two magnetic films may have substantially the same product of thickness and saturation magnetization. For example, the first magnetic film 11a has a first magnetic film thickness t1 along the first direction D1 and a first saturation magnetization Ms1. The second magnetic film 11b has a second magnetic film thickness t2 along the first direction D1 and a second saturation magnetization Ms2. In the embodiment, the first product (Ms1·t1) of the first magnetic film thickness t1 and the first saturation magnetization Ms1 may be substantially the same as the second product (Ms2·t2) of the second magnetic film thickness t2 and the second saturation magnetization Ms2. In this case, high-resolution reproduction is also possible. For example, the influence of noise is suppressed. According to the embodiment, a magnetic head with improved characteristics can be provided. For example, high-resolution reproduction is possible.

[0073] In the magnetic head 113, for example, the ratio of the absolute value of the difference between the first product and the second product to the first product may be 0.1 or less.

[0074] In the magnetic heads 110 to 113, a portion of the first shield 41 may overlap the third shield 43 and the fourth shield 44 in the first direction D1. A portion of the second shield 42 may overlap the third shield 43 and the fourth shield 44 in the first direction D1.

[0075] FIG. 11 is a schematic plan view illustrating the magnetic head according to the first embodiment. FIG. 12 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. 11, in the magnetic head 114 according to the embodiment, the reproducing section 70 includes a first magnetic layer 21 and a second magnetic layer 22. The configuration of the magnetic head 114 (and the magnetic recording device 214) other than this may be similar to the configuration of the magnetic head 112 (and the magnetic recording device 212), for example.

[0076] In the magnetic head 114, the first magnetic element 11 is provided between the first magnetic layer 21 and the second magnetic layer 22 in the first direction D1. The first magnetic layer magnetization 21M of the first magnetic layer 21 includes a component (first magnetic layer component) along the third direction D3 that intersects with the medium facing surface 10F. The second magnetic layer magnetization 22M of the second magnetic layer 22 includes a second magnetic layer component. The second magnetic layer component is along the third direction D3 or a fourth direction D4 that is opposite to the third direction D3. In this example, the second magnetic layer component is along the third direction D3.

[0077] In the magnetic head 114, for example, a portion of the first shield 41 is located between the first non-magnetic layer 31 and the first magnetic layer 21. A portion of the second shield 42 is located between the second non-magnetic layer 32 and the second magnetic layer 22. These magnetic layers control the magnetization of these shields. These magnetic layers function as, for example, pinned layers. In the magnetic head 114, the thickness of the second magnetic film 11b may be different from or the same as the thickness of the first magnetic film 11a.

[0078] FIG. 13 is a schematic plan view illustrating the magnetic head according to the first embodiment. FIG. 14 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. 13, in the magnetic head 115 according to the embodiment, the reproducing section 70 includes a first magnetic layer 21 and a second magnetic layer 22. In the magnetic head 115, the magnetization direction of the second magnetic layer 22 is different from that in the magnetic head 115. Except for this, the configuration of the magnetic head 115 (and the magnetic recording device 215) may be similar to the configuration of the magnetic head 114 (and the magnetic recording device 214), for example.

[0079] In the magnetic head 115, the first magnetic element 11 is provided between the first magnetic layer 21 and the second magnetic layer 22 in the first direction D1. The first magnetic layer magnetization 21M of the first magnetic layer 21 includes a component (first magnetic layer component) along a third direction D3 that intersects with the medium facing surface 10F. The second magnetic layer magnetization 22M of the second magnetic layer 22 includes a second magnetic layer component. The second magnetic layer component is along a fourth direction D4 that is opposite to the third direction D3.

[0080] In the magnetic head 115, the magnetization of the shield is controlled by the magnetic layers. These magnetic layers function as, for example, pinned layers. In the magnetic head 115, the thickness of the second magnetic film 11b may be different from or the same as the thickness of the first magnetic film 11a.

[0081] FIG. 15 is a schematic plan view illustrating the magnetic head according to the first embodiment. FIG. 16 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. 15, in the magnetic head 116 according to the embodiment, the reproducing section 70 includes a first magnetic layer 21, a second magnetic layer 22, a third magnetic layer 23, and a fourth magnetic layer 24. The configuration of the magnetic head 116 (and the magnetic recording device 216) other than this may be similar to the configuration of the magnetic head 114 (and the magnetic recording device 214), for example.

[0082] In the magnetic head 116, the reproducing section 70 includes a third magnetic layer 23 containing IrMn and a fourth magnetic layer 24 containing IrMn. The first magnetic layer 21 is provided between the third magnetic layer 23 and the first non-magnetic layer 31. The second magnetic layer 22 is provided between the second non-magnetic layer 32 and the fourth magnetic layer 24. The third magnetic layer 23 is provided between the first shield 41 and the first magnetic layer 21. The fourth magnetic layer 24 is provided between the second magnetic layer 22 and the second shield 42.

[0083] The third magnetic layer 23 controls the first magnetic layer magnetization 21M of the first magnetic layer 21. The fourth magnetic layer 24 controls the second magnetic layer magnetization 22M of the second magnetic layer 22.

[0084] In the magnetic head 116, the first magnetic layer magnetization 21M includes a component along the third direction D3, and the second magnetic layer magnetization 22M includes a component along the third direction D3.

[0085] 16 , the length of the first magnetic layer 21 along the third direction D3 may be longer than the length of the first magnetic element 11 along the third direction D3. The length of the second magnetic layer 22 along the third direction D3 may be longer than the length of the first magnetic element 11 along the third direction D3. The length of the third magnetic layer 23 along the third direction D3 may be longer than the length of the first magnetic element 11 along the third direction D3. The length of the fourth magnetic layer 24 along the third direction D3 may be longer than the length of the first magnetic element 11 along the third direction D3.

[0086] FIG. 17 is a schematic plan view illustrating the magnetic head according to the first embodiment. FIG. 18 is a schematic perspective view illustrating a part of the magnetic head according to the first embodiment. 17, in the magnetic head 117 according to the embodiment, the magnetization direction of the second magnetic layer 22 is different from that in the magnetic head 116. Except for this, the configuration of the magnetic head 117 (and the magnetic recording device 217) may be similar to the configuration of the magnetic head 116 (and the magnetic recording device 216), for example.

[0087] In the magnetic head 117, the first magnetic layer magnetization 21M includes a component along the third direction D3, and the second magnetic layer magnetization 22M includes a component along the fourth direction D4 opposite to the third direction D3.

[0088] In the magnetic head 116 and the magnetic head 117, the thickness of the second magnetic film 11b may be different from or the same as the thickness of the first magnetic film 11a.

[0089] 19, 20, 21(a) and 21(b) are schematic views illustrating the magnetic head according to the first embodiment. Fig. 19 is a plan view. Fig. 20 is a perspective view of a portion of the magnetic head. Fig. 21(a) is a schematic cross-sectional view taken along line Y1-Y2 in Fig. 19. Fig. 21(b) is a schematic cross-sectional view taken along line Y3-Y4 in Fig. 19.

[0090] 19, in the magnetic head 118 according to the embodiment, the reproducing section 70 includes a first shield 41, a second shield 42, a third shield 43, a fourth shield 44, and a first magnetic element 11. The first magnetic element 11 is provided between the first shield 41 and the second shield 42, and between the third shield 43 and the fourth shield 44. The first shield 41 and the second shield 42 each include an inclined side. Except for this, the configuration of the magnetic head 118 (and the magnetic recording device 218) may be similar to that of, for example, the magnetic head 110 (and the magnetic recording device 210).

[0091] As shown in Fig. 20, the first shield 41 includes a first side s1. As shown in Fig. 21(a), the first side s1 includes a first end p1 and a first other end pa1.

[0092] As shown in Fig. 20, the second shield 42 includes a second side s2. As shown in Fig. 21(b), the second side s2 includes a second end p2 and a second other end pa2.

[0093] 21(a), the distance along the third direction D3 between the first end p1 and the medium facing surface 10F is shorter than the distance along the third direction D3 between the first other end pa1 and the medium facing surface 10F. The third direction D3 intersects with the medium facing surface 10F. The position of the first end p1 in the second direction D2 is between the position of at least a part of the third shield 43 in the second direction D2 and the position of the first other end pa1 in the second direction D2.

[0094] 21(b), the distance along the third direction D3 between the second end p2 and the medium facing surface 10F is shorter than the distance along the third direction D3 between the second other end pa2 and the medium facing surface 10F. The position of the second end p2 in the second direction D2 is between the position of the second other end pa2 in the second direction D2 and the position of at least a part of the fourth shield 44 in the second direction D2.

[0095] The first side s1 and the second side s2 are inclined with respect to the medium facing surface 10F. The direction of the inclination of the first side s1 is opposite to the direction of the inclination of the second side s2.

[0096] 20 , in one example, the first magnetization 41M of the first shield 41 is generally aligned along the second direction D2. The second magnetization 42M of the second shield 42 is generally aligned along the second direction D2. For example, the first magnetization 41M of the first shield 41 includes a component (first shield component) aligned along the second direction D2. For example, the second magnetization 42M of the second shield 42 includes a component (second shield component) aligned along the second direction D2.

[0097] Near the inclined first side s1 of the first shield 41, the magnetization includes a component along the third direction D3 due to the inclination. Near the inclined second side s2 of the second shield 42, the magnetization includes a component along the third direction D3 due to the inclination. The inclination directions are opposite at the first side s1 and the second side s2.

[0098] 21(a), the first shield 41 includes a first region r1 facing the first magnetic element 11. For example, the first region magnetization r1M of the first region r1 includes a component (first region component) along the third direction D3.

[0099] 21(b), the second shield 42 includes a second region r2 facing the first magnetic element 11. The second region magnetization r2M of the second region r2 includes a component (second region component) along a fourth direction D4 opposite to the third direction D3.

[0100] In this way, the angled edges may control the orientation of the magnetization in the shield.

[0101] As shown in Fig. 21(a), the first angle θ1 between the first side s1 and the third direction D3 may be, for example, 5 degrees or more and 85 degrees or less. As shown in Fig. 21(b), the second angle θ2 between the second side s2 and the third direction D3 may be, for example, 5 degrees or more and 85 degrees or less.

[0102] A portion of the first shield 41 may overlap with the third shield 43 in the first direction D1. A portion of the second shield 42 may overlap with the third shield 43 in the first direction D1.

[0103] 22, 23, 24(a) and 24(b) are schematic views illustrating the magnetic head according to the first embodiment. Fig. 22 is a plan view. Fig. 23 is a perspective view of a portion of the magnetic head. Fig. 24(a) is a schematic cross-sectional view taken along line Y1-Y2 in Fig. 22. Fig. 24(b) is a schematic cross-sectional view taken along line Y3-Y4 in Fig. 22.

[0104] 22, in the magnetic head 119 according to the embodiment, the reproducing section 70 includes a first shield 41, a second shield 42, a third shield 43, a fourth shield 44, and a first magnetic element 11. The first magnetic element 11 is provided between the first shield 41 and the second shield 42, and between the third shield 43 and the fourth shield 44. The first shield 41 and the second shield 42 each include an inclined side. The configuration of the magnetic head 119 (and the magnetic recording device 219) other than this may be similar to that of, for example, the magnetic head 112 and the magnetic head 113 (and the magnetic recording device 212 and the magnetic recording device 213).

[0105] As shown in Fig. 23, the first shield 41 includes a first side s1. As shown in Fig. 24(a), the first side s1 includes a first end p1 and a first other end pa1.

[0106] As shown in Fig. 23, the second shield 42 includes a second side s2. As shown in Fig. 24(b), the second side s2 includes a second end p2 and a second other end pa2.

[0107] 24(a), the distance along the third direction D3 between the first end p1 and the medium facing surface 10F is shorter than the distance along the third direction D3 between the first other end pa1 and the medium facing surface 10F. The third direction D3 intersects with the medium facing surface 10F. The position of the first end p1 in the second direction D2 is between the position of at least a part of the third shield 43 in the second direction D2 and the position of the first other end pa1 in the second direction D2.

[0108] 24(b), the distance along the third direction D3 between the second end p2 and the medium facing surface 10F is shorter than the distance along the third direction D3 between the second other end pa2 and the medium facing surface 10F. The position of the second end p2 in the second direction D2 is between the position of at least a part of the third shield 43 in the second direction D2 and the position of the second other end pa2 in the second direction D2.

[0109] In the magnetic head 119, the first side s1 and the second side s2 are also inclined with respect to the medium facing surface 10F. The direction of the inclination of the first side s1 is the same as the direction of the inclination of the second side s2.

[0110] 23, in one example, the first magnetization 41M of the first shield 41 is generally aligned along the second direction D2. The second magnetization 42M of the second shield 42 is generally aligned along the second direction D2. For example, the first magnetization 41M of the first shield 41 includes a component (first shield component) aligned along the second direction D2. For example, the second magnetization 42M of the second shield 42 includes a component (second shield component) aligned along the second direction D2.

[0111] Near the inclined first side s1 of the first shield 41, the magnetization includes a component along the third direction D3 due to the inclination. Near the inclined second side s2 of the second shield 42, the magnetization includes a component along the third direction D3 due to the inclination.

[0112] 24(a), the first shield 41 includes a first region r1 facing the first magnetic element 11. For example, the first region magnetization r1M of the first region r1 includes a component (first region component) along the third direction D3.

[0113] 24(b), the second shield 42 includes a second region r2 facing the first magnetic element 11. For example, the second region magnetization r2M of the second region r2 includes a component (second region component) along the third direction D3.

[0114] In this way, the angled edges may control the orientation of the magnetization in the shield.

[0115] As shown in Fig. 24(a), the first angle θ1 between the first side s1 and the third direction D3 may be, for example, 5 degrees or more and 85 degrees or less. As shown in Fig. 24(b), the second angle θ2 between the second side s2 and the third direction D3 may be, for example, 5 degrees or more and 85 degrees or less.

[0116] In the magnetic head 119, the thickness of the second magnetic film 11b may be different from or the same as the thickness of the first magnetic film 11a.

[0117] FIG. 25 is a schematic perspective view illustrating the magnetic head according to the first embodiment. 25, in the magnetic head 120 according to the embodiment, the reproducing section 70 includes a first conductive member 43C. Except for this, the configuration of the magnetic head 120 (and the magnetic recording device 220) may be similar to that of the magnetic head 110, etc. (and the magnetic recording device 210, etc.).

[0118] The first conductive member 43C electrically connects the third terminal 43T to the first magnetic element 11. In this case, the third shield 43 and the fourth shield 44 may be electrically insulated from the third terminal 43T.

[0119] (Second embodiment) The second embodiment relates to a magnetic recording device. As already explained, the magnetic recording device according to the embodiment (for example, the magnetic recording device 210) includes a magnetic head according to the embodiment (for example, the magnetic head 110) and a magnetic recording medium 80 (see FIG. 2). The magnetic recording device according to the embodiment may include any magnetic head according to the first embodiment.

[0120] The magnetic recording device may further include a first circuit 51 and a second circuit 52. As already described, the first circuit 51 is configured to supply a current between the first terminal 41T and the second terminal 42T. The second circuit 52 is configured to detect a voltage between the third terminal 43T and one of the first terminal 41T and the second terminal 42T. This voltage is configured to change depending on the magnetization state recorded on the magnetic recording medium 80.

[0121] FIG. 26 is a schematic view illustrating the magnetic recording device according to the embodiment. 26 illustrates an example of the configuration of the second circuit 52 in a magnetic recording device 230 according to the embodiment. The second circuit 52 includes a first differential circuit 52a and a second differential circuit 52b. The first differential circuit 52a includes a first input portion 52ap and a first other input portion 52an. The second differential circuit 52b includes a second input portion 52bp and a second other input portion 52bn.

[0122] For example, the first input section 52ap is the positive input of the first differential circuit 52a. For example, the first other input section 52an is the negative input of the first differential circuit 52a. For example, the second input section 52bp is the positive input of the second differential circuit 52b. For example, the second other input section 52bn is the negative input of the second differential circuit 52b.

[0123] The first input portion 52ap is electrically connected to the first terminal 41T. The first other input portion 52an is electrically connected to the third terminal 43T. The second input portion 52bp is electrically connected to the second terminal 42T. The second other input portion 52bn is electrically connected to the third terminal 43T.

[0124] 26, the first differential circuit 52a further includes a first output section 52ao. The second differential circuit 52b further includes a second output section 52bo. At least a portion of the signal (reproduced signal) from the reproducing section 70 is obtained from the first differential circuit 52a. At least a portion of the signal (reproduced signal) from the reproducing section 70 is obtained from the second differential circuit 52b.

[0125] For example, the voltage of the first output section 52ao and the voltage of the second output section 52bo change according to the information (magnetization) recorded on the magnetic recording medium 80. When the voltage of the first output section 52ao increases, the voltage of the second output section 52bo decreases. When the voltage of the first output section 52ao decreases, the voltage of the second output section 52bo increases.

[0126] The second circuit 52 may further include a third differential circuit 52c. The third differential circuit 52c includes a third input port 52cp and a third other input port 52cn. The third input port 52cp is, for example, the positive input of the third differential circuit 52c. The third other input port 52cn is, for example, the negative input of the third differential circuit 52c. The third input port 52cp is electrically connected to one of the first output port 52ao and the second output port 52bo. The third other input port 52cn is electrically connected to the other of the first output port 52ao and the second output port 52bo.

[0127] For example, the difference between the potential of the first output port 52ao and the potential of the second output port 52bo is output from the third output port 52co of the third differential circuit 52c. Differential processing can, for example, obtain a signal with higher strength. For example, a signal with reduced noise can be obtained. Generation can be performed with higher accuracy. The signal obtained from the third output port 52co can be supplied to a voltmeter 52d.

[0128] The configuration described with respect to the magnetic recording device 230 may be applied to any magnetic recording device according to the embodiment.

[0129] An example of the configuration of the magnetic head and magnetic recording device according to the embodiment will be described below. In the following example, a magnetic head 110 is used as the magnetic head according to the embodiment.

[0130] FIG. 27 is a schematic perspective view illustrating the magnetic head according to the embodiment. 27, the magnetic head 110 according to the embodiment may further include a recording unit 90. The recording unit 90 of the magnetic head 110 records information on the magnetic recording medium 80. The reproducing unit 70 reproduces the information recorded on the magnetic recording medium 80.

[0131] The magnetic recording medium 80 includes, for example, a medium substrate 82 and a magnetic recording layer 81 provided on the medium substrate 82. The magnetization 83 of the magnetic recording layer 81 is controlled by a recording unit 90. The recording unit 90 includes, for example, a first magnetic pole 91 and a second magnetic pole 92. The first magnetic pole 91 is, for example, a main magnetic pole. The second magnetic pole 92 is, for example, a trailing shield. The recording unit 90 may include a recording element 93. The recording element 93 may include a magnetic field control element, a heating element, a high-frequency oscillation element, or the like. The recording element 93 may be omitted.

[0132] The reproducing unit 70 includes, for example, a first shield 41, a second shield 42, and a first magnetic element 11. The first magnetic element 11 can output a signal according to the magnetization 83 of the magnetic recording layer 81. In FIG. 27, the third shield 43 and the fourth shield 44 are omitted.

[0133] 27, magnetic recording medium 80 moves relative to magnetic head 110 in medium movement direction 85. Information corresponding to magnetization 83 of magnetic recording layer 81 is controlled at any position by magnetic head 110. Information corresponding to magnetization 83 of magnetic recording layer 81 is reproduced at any position by magnetic head 110.

[0134] FIG. 28 is a schematic perspective view illustrating a part of the magnetic recording device according to the embodiment. FIG. 28 illustrates a head slider. The magnetic head 110 is provided 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 while floating above or in contact with the magnetic recording medium.

[0135] The head slider 159 has, for example, an air inflow side 159A and an air outflow side 159B. The magnetic head 110 is disposed on the side of the air outflow side 159B of the head slider 159. This allows the magnetic head 110 to move relative to the magnetic recording medium while floating above or in contact with the magnetic recording medium.

[0136] FIG. 29 is a schematic perspective view illustrating the magnetic recording device according to the embodiment. 30A and 30B are schematic perspective views illustrating a part of the magnetic recording device according to the embodiment. The magnetic recording device may be a magnetic recording and reproducing device. As shown in FIG. 29, a rotary actuator is used in the magnetic recording device 150 according to the embodiment. The recording medium disk 180 is mounted on a spindle motor 180M. The recording medium disk 180 is rotated in the direction of the arrow AR by the spindle motor 180M. The spindle motor 180M responds to a control signal from a drive control unit. The magnetic recording device 150 according to the embodiment may include a plurality of recording medium disks 180. The magnetic recording device 150 may include a recording medium 181. The recording medium 181 is, for example, an SSD (Solid State Drive). The recording medium 181 may be, for example, a non-volatile memory such as a flash memory. For example, the magnetic recording device 150 may be a hybrid HDD (Hard Disk Drive).

[0137] The head slider 159 records and reproduces information to be recorded on the recording medium disk 180. The head slider 159 is provided at the tip of the thin-film suspension 154. Near the tip of the head slider 159, a magnetic head according to the embodiment is provided.

[0138] When the recording medium disk 180 rotates, the pressing pressure from the suspension 154 and the pressure generated at the air bearing surface (ABS) of the head slider 159 are balanced. The distance between the air bearing surface of the head slider 159 and the surface of the recording medium disk 180 is a predetermined flying height. In an embodiment, the head slider 159 may be in contact with the recording medium disk 180. For example, a contact traveling type may be applied.

[0139] The suspension 154 is connected to one end of an arm 155 (e.g., an actuator arm). The arm 155 has, for example, a bobbin portion. The bobbin portion 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 portion 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. The magnetic head is provided at one end of the suspension 154. The arm 155 is connected to the other end of the suspension 154.

[0140] Arm 155 is held by ball bearings. The ball bearings are provided at two locations, above and below bearing portion 157. Arm 155 can rotate and slide using voice coil motor 156. The magnetic head can be moved to any position on recording medium disk 180.

[0141] FIG. 30(a) is an enlarged perspective view of a head stack assembly 160, illustrating the configuration of a portion of the magnetic recording device. FIG. 30(b) is a perspective view illustrating a magnetic head assembly (head gimbal assembly: HGA) 158 that is part of the head stack assembly 160.

[0142] 30(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 in the opposite direction to the extension direction of the head gimbal assembly 158. The support frame 161 supports a coil 162 of the voice coil motor 156.

[0143] As shown in FIG. 30( b ), the head gimbal assembly 158 has an arm 155 extending from a bearing portion 157 and a suspension 154 extending from the arm 155 .

[0144] A head slider 159 is provided at the tip of the suspension 154. The head slider 159 is provided with the magnetic head according to the embodiment.

[0145] A magnetic head assembly (head gimbal assembly) 158 according to the embodiment includes a magnetic head according to the embodiment, a head slider 159 provided with the magnetic head, 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.

[0146] The suspension 154 has, for example, lead wires (not shown) for recording and reproducing signals. The suspension 154 may also have, for example, lead wires (not shown) for a heater for adjusting the flying height. The suspension 154 may also have lead wires (not shown) for an oscillation element, for example. These lead wires are electrically connected to a plurality of electrodes provided on the magnetic head.

[0147] The magnetic recording device 150 is provided with a signal processing unit 190. The signal processing unit 190 uses a magnetic head to record and reproduce signals on a magnetic recording medium. Input / output lines of the signal processing unit 190 are connected to, for example, electrode pads of the head gimbal assembly 158, and are electrically connected to the magnetic head.

[0148] The magnetic recording device 150 according to the embodiment includes a magnetic recording medium, a magnetic head according to the embodiment, a movable unit, a position control unit, and a signal processing unit. The movable unit enables the magnetic recording medium and the magnetic head to be moved relatively while being separated from each other or in contact with each other. The position control unit aligns the magnetic head with 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.

[0149] For example, the magnetic recording medium is a recording medium disk 180. The movable part includes, for example, a head slider 159. The position control unit includes, for example, a head gimbal assembly 158.

[0150] The embodiments may include the following technical solutions. (Technical proposal 1) a reproducing section including a medium-facing surface; The playback unit A first shield; a second shield, the direction from the first shield to the second shield being along a first direction along the medium facing surface; The third shield, a fourth shield, wherein a second direction from the third shield to the fourth shield is along the medium facing surface and intersects with the first direction; a first magnetic element provided between the first shield and the second shield and between the third shield and the fourth shield; a first nonmagnetic layer provided between the first shield and the first magnetic element; a second nonmagnetic layer provided between the first magnetic element and the second shield; a first terminal electrically connected to the first shield; a second terminal electrically connected to the second shield; a third terminal electrically connected to the first magnetic element; Including, the first nonmagnetic layer includes a first surface facing the first shield; the second nonmagnetic layer includes a second surface facing the second shield, a first ratio of a second length in the second direction of the first magnetic element to a first distance in the first direction between the first surface and the second surface is 0.6 or greater;

[0151] (Technical proposal 2) the first nonmagnetic layer is in contact with the first magnetic element; the second nonmagnetic layer is in contact with the first magnetic element, The magnetic head described in Technical Solution 1, wherein at least one of the first non-magnetic layer and the second non-magnetic layer contains at least one selected from the group consisting of Cu, Al, Au, Ag, W, Ta, Si, C, AlO, and MgO.

[0152] (Technical proposal 3) the reproducing section further includes a third nonmagnetic layer provided between the third shield and the first magnetic element, the third nonmagnetic layer is electrically connected to the third shield and the first magnetic element; the third terminal is electrically connected to the third shield; The magnetic head according to Technical Solution 1 or 2, wherein the third non-magnetic layer contains at least one selected from the group consisting of Cu, Al, Au, and Ag.

[0153] (Technical proposal 4) a reproducing section including a medium-facing surface; The playback unit A first shield; a second shield, the direction from the first shield to the second shield being along a first direction along the medium facing surface; The third shield, a fourth shield, wherein a second direction from the third shield to the fourth shield is along the medium facing surface and intersects with the first direction; a first magnetic element provided between the first shield and the second shield and between the third shield and the fourth shield; a first nonmagnetic layer provided between the first shield and the first magnetic element; a second nonmagnetic layer provided between the first magnetic element and the second shield; a first terminal electrically connected to the first shield; a second terminal electrically connected to the second shield; a third terminal electrically connected to the first magnetic element; Including, the first nonmagnetic layer includes a first surface facing the first shield; the second nonmagnetic layer includes a second surface facing the second shield, The second ratio is 0.7 or more, the second ratio is a ratio of a ½ power of a product of a second length of the first magnetic element in the second direction and a third length of the first magnetic element in the third direction to a first distance in the first direction between the first surface and the second surface; The magnetic head, wherein the third direction intersects with the medium-facing surface.

[0154] (Technical proposal 5) the first magnetization of the first shield includes a first component in a third direction that intersects with the medium facing surface; The magnetic head according to any one of Technical Solutions 1 to 3, wherein the second magnetization of the second shield includes a second component in a fourth direction opposite to the third direction.

[0155] (Technical proposal 6) The first magnetic element is a first magnetic film; a second magnetic film provided between the first magnetic film and the second shield; a first non-magnetic film provided between the first magnetic film and the second magnetic film; Including, the first non-magnetic film includes at least one selected from the group consisting of Cu, Ru, Ir, and Au; a first non-magnetic film thickness along the first direction of the first non-magnetic film is 0.1 nm or more and 10 nm or less; the first magnetic film has a first magnetic film thickness along the first direction, the second magnetic film has a second magnetic film thickness along the first direction, The magnetic head according to any one of Technical Solutions 1 to 3, wherein the first magnetic film thickness is thinner than the second magnetic film thickness.

[0156] (Technical proposal 7) The first magnetic element is a first magnetic film; a second magnetic film provided between the first magnetic film and the second shield; a first non-magnetic film provided between the first magnetic film and the second magnetic film; Including, the first non-magnetic film includes at least one selected from the group consisting of Cu, Ru, Ir, and Au; a first non-magnetic film thickness along the first direction of the first non-magnetic film is 0.1 nm or more and 10 nm or less; the first magnetic film has a first magnetic film thickness along the first direction and a first saturation magnetization; the second magnetic film has a second magnetic film thickness along the first direction and a second saturation magnetization; The magnetic head according to any one of Technical Solutions 1 to 3, wherein a first product of the first magnetic film thickness and the first saturation magnetization is smaller than a second product of the second magnetic film thickness and the second saturation magnetization.

[0157] (Technical proposal 8) The first magnetic element is a first magnetic film; a second magnetic film provided between the first magnetic film and the second shield; a first non-magnetic film provided between the first magnetic film and the second magnetic film; Including, the first non-magnetic film includes at least one selected from the group consisting of Cu, Ru, Ir, and Au; a first non-magnetic film thickness along the first direction of the first non-magnetic film is 0.1 nm or more and 10 nm or less; the first magnetic film has a first magnetic film thickness along the first direction, the second magnetic film has a second magnetic film thickness along the first direction, The magnetic head according to any one of Technical Solutions 1 to 3, wherein the first magnetic film thickness is substantially the same as the second magnetic film thickness.

[0158] (Technical proposal 9) The first magnetic element is a first magnetic film; a second magnetic film provided between the first magnetic film and the second shield; a first non-magnetic film provided between the first magnetic film and the second magnetic film; Including, the first non-magnetic film includes at least one selected from the group consisting of Cu, Ru, Ir, and Au; a first non-magnetic film thickness along the first direction of the first non-magnetic film is 0.1 nm or more and 10 nm or less; the first magnetic film has a first magnetic film thickness along the first direction and a first saturation magnetization; the second magnetic film has a second magnetic film thickness along the first direction and a second saturation magnetization; A magnetic head described in any one of technical proposals 1 to 3, wherein a first product of the first magnetic film thickness and the first saturation magnetization is substantially the same as a second product of the second magnetic film thickness and the second saturation magnetization.

[0159] (Technical proposal 10) the reproducing unit further includes a first magnetic layer and a second magnetic layer; the first magnetic element is provided between the first magnetic layer and the second magnetic layer in the first direction; the first magnetic layer magnetization of the first magnetic layer includes a first magnetic layer component along a third direction intersecting the medium facing surface, A magnetic head described in any one of technical proposals 1 to 3, wherein the second magnetic layer magnetization of the second magnetic layer includes a second magnetic layer component, and the second magnetic layer component is along the third direction or along a fourth direction opposite to the third direction.

[0160] (Technical proposal 11) The playback unit a third magnetic layer containing IrMn; a fourth magnetic layer containing IrMn; further comprising the first magnetic layer is provided between the third magnetic layer and the first non-magnetic layer, The magnetic head described in Technical Solution 10, wherein the second magnetic layer is provided between the second non-magnetic layer and the fourth magnetic layer.

[0161] (Technical proposal 12) the third magnetic layer is provided between the first shield and the first magnetic layer, The magnetic head described in Technical Solution 11, wherein the fourth magnetic layer is provided between the second magnetic layer and the second shield.

[0162] (Technical proposal 13) the first shield includes a first side including a first end and a first other end; the second shield includes a second side including a second end and a second other end; a distance along the third direction between the first end and the medium facing surface is shorter than a distance along the third direction between the first other end and the medium facing surface; the third direction intersects with the medium facing surface, a position of the first end in the second direction is between a position of at least a portion of the third shield in the second direction and a position of the first other end in the second direction, a distance along the third direction between the second end and the medium facing surface is shorter than a distance along the third direction between the second other end and the medium facing surface; A magnetic head described in any one of technical proposals 1 to 3, wherein the position of the second end in the second direction is between the position of the second other end in the second direction and the position of at least a portion of the fourth shield in the second direction.

[0163] (Technical proposal 14) the first shield includes a first side including a first end and a first other end; the second shield includes a second side including a second end and a second other end; a distance along the third direction between the first end and the medium facing surface is shorter than a distance along the third direction between the first other end and the medium facing surface; the third direction intersects with the medium facing surface, a position of the first end in the second direction is between a position of at least a portion of the third shield in the second direction and a position of the first other end in the second direction, a distance along the third direction between the second end and the medium facing surface is shorter than a distance along the third direction between the second other end and the medium facing surface; A magnetic head described in any one of technical proposals 1 to 3, wherein the position of the second end in the second direction is between the position of at least a portion of the third shield in the second direction and the position of the second other end in the second direction.

[0164] (Technical proposal 15) the first magnetization of the first shield includes a first shield component along the second direction; A magnetic head according to technical proposal 13 or 14, wherein the second magnetization of the second shield includes a second shield component along the second direction.

[0165] (Technical proposal 16) the first shield includes a first region facing the first magnetic element; the second shield includes a second region facing the first magnetic element; a first region magnetization of the first region including a first region component along the third direction; The magnetic head according to any one of Technical Solutions 13 to 15, wherein the second region magnetization of the second region includes a second region component along a fourth direction opposite to the third direction.

[0166] (Technical proposal 17) the reproducing unit further includes a first conductive member electrically connecting the third terminal to the first magnetic element; The magnetic head according to any one of Technical Solutions 1 to 16, wherein the third shield and the fourth shield are electrically insulated from the third terminal.

[0167] (Technical proposal 18) A magnetic head according to any one of technical proposals 1 to 17; a magnetic recording medium facing the magnetic head; The first circuit, A second circuit; Equipped with the first circuit is configured to supply a current between the first terminal and the second terminal; the second circuit is configured to detect a voltage between the third terminal and one of the first terminal and the second terminal; A magnetic recording device configured such that the voltage changes depending on the magnetization state recorded on the magnetic recording medium.

[0168] (Technical proposal 19) The second circuit is a first differential circuit including a first input section and a first other input section; a second differential circuit including a second input section and a second other input section; Including, the first input unit is electrically connected to the first terminal, the first other input unit is electrically connected to the third terminal, the second input unit is electrically connected to the second terminal, The magnetic recording device according to Technical Solution 18, wherein the second other input unit is electrically connected to the third terminal.

[0169] (Technical proposal 20) the first differential circuit further includes a first output section; the second differential circuit further includes a second output section; the second circuit further includes a third differential circuit including a third input section and a third other input section; the third input unit is electrically connected to one of the first output unit and the second output unit; The magnetic recording device described in Technical Solution 19, wherein the third other input unit is electrically connected to the other of the first output unit and the second output unit.

[0170] According to the embodiment, it is possible to provide a magnetic head and a magnetic recording device that can obtain stable characteristics.

[0171] In this specification, "vertical" and "parallel" do not only mean strictly vertical and strictly parallel, but also include variations in the manufacturing process, and may mean substantially vertical and substantially parallel.

[0172] 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 configurations of the elements included in the magnetic head and magnetic recording device, such as the shield, magnetic element, and terminals, are within the scope of the present invention as long as a person skilled in the art can implement the present invention in a similar manner and obtain similar effects by appropriately selecting them from known ranges.

[0173] Any combination of two or more elements of each embodiment to the extent technically possible is also included within the scope of the present invention as long as it encompasses the gist of the present invention.

[0174] In addition, all magnetic heads and magnetic recording devices that can be implemented by a person skilled in the art by appropriately modifying the design based on the magnetic heads and magnetic recording devices described above as embodiments of the present invention also fall within the scope of the present invention, as long as they include the gist of the present invention.

[0175] In addition, within the scope of the concept of the present invention, a person skilled in the art may come up with various modifications and alterations, and it will be understood that these modifications and alterations also fall within the scope of the present invention.

[0176] Although several 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 embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0177] 10F: medium facing surface, 11: first magnetic element, 11a, 11b: first and second magnetic films, 11c: first non-magnetic film, 21-24: first to fourth magnetic layers, 21M, 22M: first and second magnetic layer magnetizations, 30i: insulating member, 31-33: first to third non-magnetic layers, 31F, 32F: first and second surfaces, 41-44: first to fourth shields, 41M, 42M: first and second magnetizations, 41T-43T: first to third terminals, 43C: first conductive member, 51, 52: first and second circuits, 52a, 52b, 52c: first to third differential circuits, 52an, 52bn, 52cn: first to third other input sections, 52ao, 52bo, 52co: first to third output sections, 52ap, 52bp, 52cp: first to third input sections, 52d: voltmeter, 70: reproduction section, 80: magnetic recording medium, 81: magnetic recording layer, 82: medium substrate, 83: magnetization, 85: medium movement direction, 90: recording section, 91, 92: first and second magnetic poles, 93: recording section element, 110-120: 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, 210-220, 230: magnetic recording device, AR: arrow, D1-D4: first to fourth directions, H1: magnetic field, LN1: first distance, LN2: second length, M, Mz: magnetization, P1: parameter, R1: first ratio, p1, p2: first and second ends, pa1, pa2: first and second other ends, r1, r2: first and second regions, r1M, r2M: first and second region magnetization, s1, s2: first and second sides, t1, t2: first and second magnetic film thicknesses, t3...first non-magnetic film thickness, θ1, θ2: first and second angles

Claims

1. a reproducing section including a medium-facing surface; The playback unit A first shield; a second shield, the direction from the first shield to the second shield being along a first direction along the medium facing surface; A third shield; and a fourth shield, wherein a second direction from the third shield to the fourth shield is along the medium facing surface and intersects with the first direction; a first magnetic element provided between the first shield and the second shield and between the third shield and the fourth shield; a first nonmagnetic layer provided between the first shield and the first magnetic element; a second nonmagnetic layer provided between the first magnetic element and the second shield; a first terminal electrically connected to the first shield; a second terminal electrically connected to the second shield; a third terminal electrically connected to the first magnetic element; Including, the first nonmagnetic layer includes a first surface facing the first shield, the second nonmagnetic layer includes a second surface facing the second shield, A magnetic head, wherein a first ratio of a second length in the second direction of the first magnetic element to a first distance in the first direction between the first surface and the second surface is 0.6 or greater.

2. a reproducing section including a medium-facing surface; The playback unit A first shield; a second shield, the direction from the first shield to the second shield being along a first direction along the medium facing surface; A third shield; and a fourth shield, wherein a second direction from the third shield to the fourth shield is along the medium facing surface and intersects with the first direction; a first magnetic element provided between the first shield and the second shield and between the third shield and the fourth shield; a first nonmagnetic layer provided between the first shield and the first magnetic element; a second nonmagnetic layer provided between the first magnetic element and the second shield; a first terminal electrically connected to the first shield; a second terminal electrically connected to the second shield; a third terminal electrically connected to the first magnetic element; Including, the first nonmagnetic layer includes a first surface facing the first shield, the second nonmagnetic layer includes a second surface facing the second shield, the second ratio is equal to or greater than 0.7; the second ratio is a ratio of a ½ power of a product of a second length of the first magnetic element in the second direction and a third length of the first magnetic element in the third direction to a first distance in the first direction between the first surface and the second surface; The magnetic head, wherein the third direction intersects with the medium-facing surface.

3. the first magnetization of the first shield includes a first component in a third direction that intersects with the medium facing surface; The magnetic head of claim 1 , wherein the second magnetization of the second shield includes a second component in a fourth direction opposite the third direction.

4. The first magnetic element is a first magnetic film; a second magnetic film provided between the first magnetic film and the second shield; a first non-magnetic film provided between the first magnetic film and the second magnetic film; Including, the first non-magnetic film includes at least one selected from the group consisting of Cu, Ru, Ir, and Au; a first non-magnetic film thickness along the first direction of the first non-magnetic film is 0.1 nm or more and 10 nm or less; the first magnetic film has a first magnetic film thickness along the first direction, the second magnetic film has a second magnetic film thickness along the first direction, 2. The magnetic head according to claim 1, wherein the first magnetic film thickness is thinner than the second magnetic film thickness.

5. The first magnetic element is a first magnetic film; a second magnetic film provided between the first magnetic film and the second shield; a first non-magnetic film provided between the first magnetic film and the second magnetic film; Including, the first non-magnetic film includes at least one selected from the group consisting of Cu, Ru, Ir, and Au; a first non-magnetic film thickness along the first direction of the first non-magnetic film is 0.1 nm or more and 10 nm or less; the first magnetic film has a first magnetic film thickness along the first direction, the second magnetic film has a second magnetic film thickness along the first direction, 2. The magnetic head according to claim 1, wherein the first magnetic film thickness is substantially the same as the second magnetic film thickness.

6. the reproducing section further includes a first magnetic layer and a second magnetic layer; the first magnetic element is provided between the first magnetic layer and the second magnetic layer in the first direction; the first magnetic layer magnetization of the first magnetic layer includes a first magnetic layer component along a third direction intersecting the medium facing surface, 2. The magnetic head of claim 1, wherein the second magnetic layer magnetization of the second magnetic layer includes a second magnetic layer component, and the second magnetic layer component is aligned along the third direction or along a fourth direction opposite to the third direction.

7. the first shield includes a first side including a first end and a first other end; the second shield includes a second side including a second end and a second other end; a distance along the third direction between the first end and the medium facing surface is shorter than a distance along the third direction between the first other end and the medium facing surface; the third direction intersects with the medium facing surface, a position of the first end in the second direction is between a position of at least a portion of the third shield in the second direction and a position of the first other end in the second direction, a distance along the third direction between the second end and the medium facing surface is shorter than a distance along the third direction between the second other end and the medium facing surface; The magnetic head according to claim 1 , wherein the position of the second end in the second direction is between the position of the second other end in the second direction and the position of at least a portion of the fourth shield in the second direction.

8. the first shield includes a first side including a first end and a first other end; the second shield includes a second side including a second end and a second other end; a distance along the third direction between the first end and the medium facing surface is shorter than a distance along the third direction between the first other end and the medium facing surface; the third direction intersects with the medium facing surface, a position of the first end in the second direction is between a position of at least a portion of the third shield in the second direction and a position of the first other end in the second direction, a distance along the third direction between the second end and the medium facing surface is shorter than a distance along the third direction between the second other end and the medium facing surface; The magnetic head of claim 1 , wherein the position of the second end in the second direction is between the position of the at least part of the third shield in the second direction and the position of the second other end in the second direction.

9. A magnetic head according to any one of claims 1 to 8, a magnetic recording medium facing the magnetic head; A first circuit; A second circuit; Equipped with the first circuit is configured to supply a current between the first terminal and the second terminal; the second circuit is configured to detect a voltage between the third terminal and one of the first terminal and the second terminal; A magnetic recording device configured such that the voltage changes depending on the magnetization state recorded on the magnetic recording medium.

10. The second circuit is a first differential circuit including a first input section and a first other input section; a second differential circuit including a second input section and a second other input section; Including, the first input unit is electrically connected to the first terminal, the first other input unit is electrically connected to the third terminal, the second input unit is electrically connected to the second terminal, The magnetic recording device according to claim 9 , wherein the second other input section is electrically connected to the third terminal.

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