Magnetic head and magnetic recording device

According to one embodiment, a magnetic head includes a first magnetic pole, a second magnetic pole, and a magnetic element provided between the first and the second magnetic poles. The magnetic element includes first to fifth magnetic layers, and first to sixth non-magnetic layers. The sixth non-magnetic layer is provided between the fifth magnetic layer and the second magnetic pole. The sixth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2023-031361, filed on Mar. 1, 2023; the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a magnetic head and a magnetic recording device.

BACKGROUND

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

DETAILED DESCRIPTION

According to one embodiment, a magnetic head includes a first magnetic pole, a second magnetic pole, and a magnetic element provided between the first magnetic pole and the second magnetic pole. The magnetic element includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic pole, a third magnetic layer provided between the second magnetic layer and the second magnetic pole, a fourth magnetic layer provided between the third magnetic layer and the second magnetic pole, a fifth magnetic layer provided between the fourth magnetic layer and the second magnetic pole, a first non-magnetic layer provided between the first magnetic pole and the first magnetic layer, a second non-magnetic layer provided between the first magnetic layer and the second magnetic layer, a third non-magnetic layer provided between the second magnetic layer and the third magnetic layer, a fourth non-magnetic layer provided between the third magnetic layer and the fourth magnetic layer, a fifth non-magnetic layer provided between the fourth magnetic layer and the fifth magnetic layer, and a sixth non-magnetic layer provided between the fifth magnetic layer and the second magnetic pole. The sixth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

First Embodiment

FIG.1is a schematic cross-sectional view illustrating a magnetic head according to a first embodiment.

FIG.2is a schematic plan view illustrating the magnetic head according to the first embodiment.

FIG.3is a schematic cross-sectional view illustrating the magnetic recording device including the magnetic head according to the first embodiment.

As shown inFIG.3, a magnetic recording device210according to the embodiment includes a magnetic head110and a controller75. The magnetic recording device210may include a magnetic recording medium80. At least a recording operation is performed in the magnetic recording device210. In the recording operation, information is recorded on the magnetic recording medium80using the magnetic head110.

The magnetic head110includes a first magnetic pole31, a second magnetic pole32and a magnetic element20. The magnetic head110may include coil30c. The first magnetic pole31, the second magnetic pole32, the magnetic element20and the coil30care included in the recording section60. As will be described below, the magnetic head110may include a reproducing section. The magnetic element20is provided between the first magnetic pole31and the second magnetic pole32.

For example, the first magnetic pole31and the second magnetic pole32form a magnetic circuit. The first magnetic pole31is, for example, a main magnetic pole. The second magnetic pole32is, for example, a trailing shield. The first magnetic pole31may be the trailing shield and the second magnetic pole32may be the main pole.

A direction from the magnetic recording medium80to the magnetic head110is defined as a Z-axis direction. One direction perpendicular to the Z-axis direction is defined as an X-axis direction. A direction perpendicular to the Z-axis direction and the X-axis direction is defined as a Y-axis direction. The Z-axis direction corresponds to, for example, the height direction. The X-axis direction corresponds to, for example, the down-track direction. The Y-axis direction corresponds to, for example, the cross-track direction. The magnetic recording medium80and the magnetic head110move relatively along the down-track direction. A recording magnetic field generated by a magnetic head110is applied to a desired position on the magnetic recording medium80. Magnetization at a desired position of the magnetic recording medium80is controlled in a direction according to the recording magnetic field. Thus, information is recorded on the magnetic recording medium80.

A direction from the first magnetic pole31to the second magnetic pole32is defined as a first direction D1. The first direction D1is substantially along the X-axis direction. In the embodiments, the first direction D1may be inclined with respect to the X-axis direction. The angle of inclination is, for example, more than 0 degrees and not more than 30 degrees.

In this example, a portion of coil30cis provided between the first magnetic pole31and the second magnetic pole32. In this example, a shield33is provided. The first magnetic pole31is provided between the shield33and the second magnetic pole32in the X-axis direction. Another portion of coil30cis provided between the shield33and the first magnetic pole31. An insulating portion30iis provided between these multiple elements. The shield33is, for example, a leading shield. The magnetic head110may also include side shields (not shown).

As shown inFIG.3, the first magnetic pole31includes a medium facing surface30F. The medium facing surface30F is, for example, an ABS (Air Bearing Surface). The medium facing surface30F faces the magnetic recording medium80, for example. The medium facing surface30F extends, for example, along the X-Y plane.

As shown inFIG.3, the controller75includes a recording circuit30D and an element circuit20D. A recording current Iw is supplied from the recording circuit30D to the coil30c. For example, a first coil terminal Tc1and a second coil terminal Tc2are provided on the coil30c. The recording current Iw is supplied to the coil30cvia these coil terminals. The recording magnetic field corresponding to the recording current Iw is applied to the magnetic recording medium80from the first magnetic pole31.

As shown inFIG.3, the element circuit20D is electrically connected to the magnetic element20. In this example, the magnetic element20is electrically connected to the first magnetic pole31and the second magnetic pole32. In the magnetic head110, a first terminal T1and a second terminal T2are provided. The first terminal T1is electrically connected to one end of the magnetic element20via the first wiring W1and the first magnetic pole31. The second terminal T2is electrically connected to the other end of the magnetic element20via the second wiring W2and the second magnetic pole32. For example, an element current ic is supplied to the magnetic element20from the element circuit20D. The element current ic is direct current, for example.

The element circuit20D applies an element voltage Ve1between the first terminal T1and the second terminal T2. The element current ic based on the element voltage Ve1flows through the magnetic element20.

For example, by the element current ic equal to or higher than a threshold flowing through the magnetic element20, oscillation occurs in a magnetic layer included in the magnetic element20. The magnetic element20functions, for example, as an STO (Spin-Torque Oscillator). An alternating magnetic field (for example, a high-frequency magnetic field) is generated from the magnetic element20along with the oscillation. An alternating magnetic field generated by the magnetic element20is applied to the magnetic recording medium80to assist recording on the magnetic recording medium80. For example, MAMR (Microwave Assisted Magnetic Recording) can be performed.

As described above, the controller75is configured to supply the recording current Iw to the coil30cand supply the element current ic to the magnetic element20.

FIG.2corresponds to a plan view of the medium facing surface30F viewed from the magnetic recording medium80.

As shown inFIGS.1and2, the magnetic element20includes a first magnetic layer21, a second magnetic layer22, a third magnetic layer23, a fourth magnetic layer24, a fifth magnetic layer25, and a first non-magnetic layer.41, a second non-magnetic layer42, a third non-magnetic layer43, a fourth non-magnetic layer44, a fifth non-magnetic layer45and a sixth non-magnetic layer46.

The second magnetic layer22is provided between the first magnetic layer21and the second magnetic pole32. The third magnetic layer23is provided between the second magnetic layer22and the second magnetic pole32. The fourth magnetic layer24is provided between the third magnetic layer23and the second magnetic pole32. The fifth magnetic layer25is provided between the fourth magnetic layer24and the second magnetic pole32.

The first non-magnetic layer41is provided between the first magnetic pole31and the first magnetic layer21. The second non-magnetic layer42is provided between the first magnetic layer21and the second magnetic layer22. The third non-magnetic layer43is provided between the second magnetic layer22and the third magnetic layer23. The fourth non-magnetic layer44is provided between the third magnetic layer23and the fourth magnetic layer24. The fifth non-magnetic layer45is provided between the fourth magnetic layer24and the fifth magnetic layer25. The sixth non-magnetic layer46is provided between the fifth magnetic layer25and the second magnetic pole32.

In the embodiments, the sixth non-magnetic layer46includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

By such a configuration, highly efficient and stable oscillation can be obtained. According to the embodiments, it is possible to provide a magnetic head capable of improving the recording density. An example of simulation results of the characteristics of the magnetic element will be described below.

FIG.4is a schematic plan view illustrating a magnetic head of a reference example.

FIG.4shows a magnetic head119of a reference example. The magnetic head119has four magnetic layers and five non-magnetic layers.

FIG.5is a graph illustrating characteristics of the magnetic heads.

The horizontal axis ofFIG.5is the normalized applied voltage Vs1. The applied voltage Vs1is applied between one end of the magnetic element20and the other end. The vertical axis is the oscillation parameter Pol. The higher the oscillation parameter Pol, the higher the intensity of oscillation. InFIG.5, the characteristics of the magnetic head110according to the embodiment and the characteristics of the magnetic head119of the reference example are shown.

By a configuration in which the number of magnetic layers is five, high-intensity oscillation can be obtained. High efficiency and stable oscillation can be obtained. According to the embodiments, it is possible to provide a magnetic head capable of improving the recording density.

As described above, the sixth non-magnetic layer46includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. Thereby, providing and receiving spins between the fifth magnetic layer25and the second magnetic pole32becomes easy. For example, the second magnetic pole32functions as a spin injection layer for the fifth magnetic layer25.

In the embodiments, the first non-magnetic layer41includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W, for example. For example, the second non-magnetic layer42includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. For example, the third non-magnetic layer43includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. For example, the fourth non-magnetic layer44includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W. For example, the fifth non-magnetic layer45includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

At least one of the first magnetic layer21, the second magnetic layer22, the third magnetic layer23, the fourth magnetic layer24, or the fifth magnetic layer25includes at least one selected from the group consisting of Fr, Co, and Ni. These magnetic layers are, for example, ferromagnetic layers.

As shown inFIG.2, a thickness of the first magnetic layer21in the first direction D1is defined as a first thickness t21. The first direction D1is a direction from the first magnetic pole31to the second magnetic pole32. A thickness of the second magnetic layer22in the first direction D1is defined as a second thickness t22. A thickness of the third magnetic layer23in the first direction D1is defined as a third thickness t23. A thickness of the fourth magnetic layer24in the first direction D1is defined as a fourth thickness t24. A thickness of the fifth magnetic layer25in the first direction D1is defined as a fifth thickness t25.

In the embodiments, the second thickness t22is thicker than the first thickness t21. The second thickness t22is thicker than the third thickness t23. The second thickness t22is thicker than the fourth thickness t24. The fifth thickness t25is thicker than the first thickness t21. The fifth thickness t25is thicker than the third thickness t23. The fifth thickness t25is thicker than the fourth thickness t24.

The second magnetic layer22and the fifth magnetic layer25function, for example, oscillation layers. The first magnetic layer21, the third magnetic layer23, and the fourth magnetic layer24function, for example, as spin injection layers.

For example, when the element current ic equal to or higher than the threshold voltage flows through the magnetic element20, the magnetization22M of the second magnetic layer22and the magnetization25M of the fifth magnetic layer25oscillate. For example, an alternating magnetic field is generated.

For example, a component along the first direction D1of the magnetization24M of the fourth magnetic layer24is opposite to a component along the first direction D1of the magnetization23M of the third magnetic layer23. A component along the first direction D1of the magnetization21M of the first magnetic layer21is opposite to the component along the first direction D1of the magnetization23M of the third magnetic layer23.

As shown inFIG.2, a thickness of the first non-magnetic layer41in the first direction D1is defined as a first non-magnetic layer thickness t41. A thickness of the second non-magnetic layer42in the first direction D1is defined as a second non-magnetic layer thickness t42. A thickness of the third non-magnetic layer43in the first direction D1is defined as a third non-magnetic layer thickness t43. A thickness of the fourth non-magnetic layer44in the first direction D1is defined as a fourth non-magnetic layer thickness t44. A thickness of the fifth non-magnetic layer45in the first direction D1is defined as a fifth non-magnetic layer thickness t45. A thickness of the sixth non-magnetic layer46in the first direction D1is defined as a sixth non-magnetic layer thickness t46.

For example, the second thickness t22may be not less than 1.5 times and not more than 10 times the first thickness t21. The second thickness t22may be not less than 1.5 times and not more than 10 times the third thickness t23. The second thickness t22may be not less than 1.5 times and not more than 10 times the fourth thickness t24.

For example, the fifth thickness t25may be not less than 1.5 times and not more than 10 times the first thickness t21. The fifth thickness t25may be not less than 1.5 times and not more than 10 times the third thickness t23. The fifth thickness t25may be not less than 1.5 times and not more than 10 times the fourth thickness t24.

For example, the first thickness t21is not less than 0.5 nm and not more than 5 nm. For example, the second thickness t22is not less than 4 nm and not more than 15 nm. For example, the third thickness t23is not less than 0.5 nm and not more than 5 nm. For example, the fourth thickness t24is not less than 0.5 nm and not more than 5 nm. For example, the fifth thickness t25is not less than 4 nm and not more than 15 nm.

The first non-magnetic layer thickness t41may be, for example, not less than 1 nm and not more than 10 nm. The second non-magnetic layer thickness t42may be, for example, not less than 0.5 nm and not more than 6 nm. The third non-magnetic layer thickness t43may be, for example, not less than 0.5 nm and not more than 6 nm. The fourth non-magnetic layer thickness t44may be, for example, not less than 1 nm and not more than 10 nm. The fifth nonmagnetic layer thickness t45may be, for example, not less than 0.5 nm and not more than 6 nm. The sixth non-magnetic layer thickness t46may be, for example, not less than 0.5 nm and not more than 6 nm.

As shown inFIG.2, when the magnetic head110is in operation, the element current ic equal to or higher than the threshold value is supplied to the magnetic element20. The element current ic flows in the direction from the second magnetic pole32to the first magnetic pole31, for example. An electron flow je corresponding to the device current ic flows in the direction from the first magnetic pole31to the second magnetic pole32. The element current ic flows in the direction from the sixth non-magnetic layer46to the first non-magnetic layer41.

The element voltage Ve1is applied to the magnetic element20in the operation. A potential of the second magnetic pole32is higher than a potential of the first magnetic pole31.

The element current ic and the element voltage Ve1are supplied by the element circuit20D. For example, one end of the magnetic element20is electrically connected to the first magnetic pole31. The other end of the magnetic element20is electrically connected to the second magnetic pole32. The element circuit20D is configured to apply the element voltage Ve1between the first magnetic pole31and the second magnetic pole32. The potential of the first magnetic pole31is lower than the potential of the second magnetic pole32when the element voltage Ve1is applied.

FIG.6is a graph illustrating characteristics of the magnetic head.

FIG.6illustrates a differential electrical resistance of the magnetic element20when the voltage Vat applied to the magnetic element20is changed. The horizontal axis ofFIG.6is the voltage Vat. The vertical axis is the differential electrical resistance Rd1. The voltage Val may be the voltage between the first terminal T1and the second terminal T2. For example, a voltage corresponding to voltage Val is applied to the magnetic element20.

As shown inFIG.6, the differential electrical resistance Rd1when the voltage Val is changed includes three or more peaks. These peaks are considered to correspond to discontinuous changes in electrical resistance accompanying reversal of magnetization of the multiple magnetic layers included in the magnetic element20.

The magnetic recording device210(seeFIG.3) includes the magnetic head according to the embodiment and the controller75. The controller75includes the element circuit20D. For example, one end of the magnetic element20is electrically connected to the first magnetic pole31. The other end of the magnetic element20is electrically connected to the second magnetic pole32. The potential of the first magnetic pole31is lower than the potential of the second magnetic pole32when the element voltage Ve1is applied.

The differential electrical resistance Rd1of the magnetic element20when the voltage Val between the first magnetic pole31and the second magnetic pole32is changed includes a first negative peak n1, a first positive peak p1and a second positive peak p2. The voltage Val corresponding to the first negative peak n1is defined as a first negative peak voltage Vn1. The voltage Val corresponding to the first positive peak p1is defined as a first positive peak voltage Vp1. The voltage Val corresponding to the second positive peak p2is defined as a second positive peak voltage Vp2.

The first negative peak voltage Vn1is negative, and the first positive peak voltage Vp1and the second positive peak voltage Vp2are positive. The potential of the first magnetic pole31is higher than the potential of the second magnetic pole32when the negative voltage Vat is applied. The potential of the first magnetic pole31is lower than the potential of the second magnetic pole32when the positive voltage Vat is applied.

The first positive peak voltage Vp1is higher than the first negative peak voltage Vn1and lower than the second positive peak voltage Vp2. The element voltage Ve1is equal to or higher than the second positive peak voltage Vp2. A stable and high-intensity oscillation can be obtained. The absolute value of the first negative peak voltage Vn1may be greater than the second positive peak voltage Vp2.

Thus, the differential electrical resistance Rd1includes three or more peaks (e.g., first peak, second peak and third peak). The “first peak” is, for example, the first negative peak n1. The “second peak” is, for example, the first positive peak p1. The “third peak” is, for example, the second positive peak p2. The first negative peak voltage Vn1is, for example, the first voltage. The first positive peak voltage Vp1is, for example, the second voltage. The second positive peak voltage Vp2is, for example, the third voltage. The second voltage is between the first voltage and the third voltage. The element voltage Ve1is equal to or higher than the third voltage.

In the magnetic head110, for example, the absolute value of the element voltage Ve1is ten times or less the absolute value of the first negative peak voltage Vn1. For example, the absolute value of the element voltage Ve1may be eight times or less the absolute value of the first negative peak voltage Vn1. For example, the absolute value of the element voltage Ve1is ten times or less the absolute value of the first positive peak voltage Vp1. The absolute value of the element voltage Ve1may be eight times or less the absolute value of the first positive peak voltage Vp1.

In the magnetic head110, for example, the absolute value of the third voltage is four times or less the absolute value of the first negative peak voltage Vn1. For example, the absolute value of the third voltage may be less than or equal to three times the absolute value of the first negative peak voltage Vn1. For example, the absolute value of the third voltage is four times or less the absolute value of the first positive peak voltage Vp1. The absolute value of the third voltage may be three times or less the absolute value of the first positive peak voltage Vp1.

In the embodiments, the tail of the first positive peak p1may overlap the second positive peak p2. The tail of the second positive peak p2may overlap the first positive peak p1.

In the embodiments, the first magnetic pole31may include a plurality of magnetic regions arranged along the X-axis direction. The second magnetic pole32may include a plurality of magnetic regions arranged along the X-axis direction. The boundaries between multiple magnetic regions may be clear or unclear. For example, the multiple magnetic regions are continuous.

Examples of other configurations of the magnetic recording device according to the embodiment will be described below. An example in which the magnetic head110is used will be described below. In the following description, the “magnetic head” may be any magnetic head (or any variation thereof) according to the embodiment.

FIG.7is a schematic perspective view illustrating the magnetic recording device according to the embodiment.

As shown inFIG.7, the magnetic head (for example, the magnetic head110) according to the embodiment is used together with the magnetic recording medium80. In this example, the magnetic head110includes a recording section60and a reproducing section70. Information is recorded on the magnetic recording medium80by the recording section60of the magnetic head110. Information recorded on the magnetic recording medium80is reproduced by the reproducing section70.

The magnetic recording medium80includes, for example, a medium substrate82and a magnetic recording layer81provided on the medium substrate82. The magnetization83of the magnetic recording layer81is controlled by the recording section60.

The reproducing section70includes, for example, a first reproducing magnetic shield72a, a second reproducing magnetic shield72b, and a magnetic reproducing element71. The magnetic reproducing element71is provided between the first reproducing magnetic shield72aand the second reproducing magnetic shield72b. The magnetic reproducing element71is configured to output a signal corresponding to the magnetization83of the magnetic recording layer81.

As shown inFIG.7, the magnetic recording medium80moves relative to the magnetic head110in a direction of medium movement85. Information corresponding to the magnetization83of the magnetic recording layer81is controlled at an arbitrary position by the magnetic head110. Information corresponding to the magnetization83of the magnetic recording layer81is reproduced at an arbitrary position by the magnetic head110.

FIG.8is a schematic perspective view illustrating a part of the magnetic recording device according to the embodiment.

FIG.8illustrates a head slider.

The magnetic head110is provided on the head slider159. The head slider159includes, for example, Al2O3/TiC or the like. The head slider159moves relative to the magnetic recording medium while floating or in contact with the magnetic recording medium.

The head slider159includes, for example, an air inflow side159A and an air outflow side159B. The magnetic head110is arranged on the side surface of the air outflow side159B of the head slider159or the like. As a result, the magnetic head110moves relative to the magnetic recording medium while flying above or in contact with the magnetic recording medium.

FIG.9is a schematic perspective view illustrating the magnetic recording device according to the embodiment.

FIGS.10A and10Bare schematic perspective views illustrating a part of the magnetic recording device according to the embodiment.

As shown inFIG.9, in a magnetic recording device150according to the embodiment, a rotary actuator is used. The recording medium disk180is connected to a spindle motor180M. The recording medium disk180is rotated in a direction of arrow AR by the spindle motor180M. The spindle motor180M is responsive to control signals from the drive device controller. The magnetic recording device150according to the embodiment may include the multiple recording medium disks180. The magnetic recording device150may include a recording medium181. The recording medium181is, for example, an SSD (Solid State Drive). A non-volatile memory such as a flash memory is used for the recording medium181, for example. For example, the magnetic recording device150may be a hybrid HDD (Hard Disk Drive).

The head slider159records and reproduces information to be recorded on the recording medium disk180. The head slider159is provided at an end of a thin-film suspension154. A magnetic head according to the embodiment is provided near the end of the head slider159.

While the recording medium disk180is rotating, the pressing pressure by the suspension154and the floating pressure generated at the medium facing surface (ABS) of the head slider159are balanced. The distance between the medium facing surface of the head slider159and the surface of the recording medium disk180is the predetermined fly height. In the embodiment, the head slider159may contact the recording medium disk180. For example, a contact sliding type may be applied.

The suspension154is connected to one end of an arm155(e.g., an actuator arm). The arm155includes, for example, a bobbin part or the like. The bobbin part holds a drive coil. A voice coil motor156is provided at the other end of the arm155. The voice coil motor156is a type of linear motor. The voice coil motor156includes, for example, a drive coil and a magnetic circuit. The drive coil is wound on the bobbin part of the arm155. The magnetic circuit includes permanent magnets and opposing yokes. The drive coil is provided between the permanent magnet and the opposing yoke. The suspension154includes one end and the other end. The magnetic head is provided at one end of the suspension154. The arm155is connected to the other end of the suspension154.

The arm155is held by ball bearings. Ball bearings are provided at two locations above and below a bearing part157. The arm155can be rotated and slid by the voice coil motor156. The magnetic head can move to any position on the recording medium disk180.

FIG.10Ais an enlarged perspective view of the head stack assembly160, illustrating the configuration of a part of the magnetic recording device.

FIG.10Bis a perspective view illustrating the magnetic head assembly (head gimbal assembly: HGA)158that forms part of the head stack assembly160.

As shown inFIG.10A, the head stack assembly160includes the bearing part157, the magnetic head assembly158and a support frame161. The magnetic head assembly158extends from the bearing part157. The support frame161extends from the bearing part157. A direction in which the support frame161extends is opposite to a direction in which the magnetic head assembly158extends. The support frame161supports a coil162of the voice coil motor156.

As shown inFIG.10B, the magnetic head assembly158includes the arm155extending from the bearing part157and the suspension154extending from the arm155.

The head slider159is provided at the end of the suspension154. The head slider159is provided with the magnetic head according to the embodiment.

The magnetic head assembly158(head gimbal assembly) according to the embodiment includes the magnetic head according to the embodiment, the head slider159provided with the magnetic head, the suspension154and the arm155. The head slider159is provided at one end of the suspension154. The arm155is connected to the other end of the suspension154.

The suspension154may include, for example, a wiring (not shown) for recording and reproducing signals. The suspension154may include, for example, a heater wiring (not shown) for adjusting the fly height. The suspension154may include a wiring (not shown) for, for example, an oscillator element or the like. These wires may be electrically connected to multiple electrodes provided on the magnetic head.

A signal processor190is provided in the magnetic recording device150. The signal processor190uses a magnetic head to record and reproduce signals on a magnetic recording medium. Input/output lines of the signal processor190are connected to, for example, electrode pads of the magnetic head assembly158and electrically connected to the magnetic head.

The magnetic recording device150according to the embodiment includes the magnetic recording medium, the magnetic head according to the embodiment, a movable part, a position controller, and a signal processor. The movable part separates the magnetic recording medium from the magnetic head or makes them relatively movable while they are in contact with each other. The position controller aligns the magnetic head with a predetermined recording position on the magnetic recording medium. The signal processor records and reproduces signals on the magnetic recording medium using the magnetic head.

For example, the recording medium disk180is used as the above magnetic recording medium. The movable part includes, for example, the head slider159. The position controller described above includes, for example, the magnetic head assembly158.

The embodiments may include the following configurations (for example, technical proposals).

A magnetic head, comprising:a first magnetic pole;a second magnetic pole; anda magnetic element provided between the first magnetic pole and the second magnetic pole,the magnetic element includinga first magnetic layer,a second magnetic layer provided between the first magnetic layer and the second magnetic pole,a third magnetic layer provided between the second magnetic layer and the second magnetic pole,a fourth magnetic layer provided between the third magnetic layer and the second magnetic pole,a fifth magnetic layer provided between the fourth magnetic layer and the second magnetic pole,a first non-magnetic layer provided between the first magnetic pole and the first magnetic layer,a second non-magnetic layer provided between the first magnetic layer and the second magnetic layer,a third non-magnetic layer provided between the second magnetic layer and the third magnetic layer,a fourth non-magnetic layer provided between the third magnetic layer and the fourth magnetic layer,a fifth non-magnetic layer provided between the fourth magnetic layer and the fifth magnetic layer, anda sixth non-magnetic layer provided between the fifth magnetic layer and the second magnetic pole,the sixth non-magnetic layer including at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.
Configuration 2

The magnetic head according to Configuration 1, whereinthe first non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W,the second non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,the third non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,the fourth non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W, andThe fifth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.
Configuration 3

The magnetic head according to Configuration 2, whereina second thickness of the second magnetic layer in a first direction from the first magnetic pole to the second magnetic pole is thicker than a first thickness of the first magnetic layer in the first direction,the second thickness is thicker than a third thickness of the third magnetic layer in the first direction,the second thickness is thicker than a fourth thickness of the fourth magnetic layer in the first direction, anda fifth thickness of the fifth magnetic layer in the first direction is thicker than the first thickness, thicker than the third thickness, and thicker than the fourth thickness.
Configuration 4

The magnetic head according to Configuration 3, whereinthe second thickness is not less than 1.5 times and not more than 10 times the first thickness,the second thickness is not less than 1.5 times and not more than 10 times the third thickness,the second thickness is not less than 1.5 times and not more than 10 times the fourth thickness,the fifth thickness is not less than 1.5 times and not more than 10 times the first thickness,the fifth thickness is not less than 1.5 times and not more than 10 times the third thickness, andthe fifth thickness is not less than 1.5 times and not more than 10 times the fourth thickness.
Configuration 5

The magnetic head according to Configuration 3, whereinthe first thickness is not less than 0.5 nm and not more than 5 nm,the second thickness is not less than 4 nm and not more than 10 nm,the third thickness is not less than 0.5 nm and not more than 5 nm,the fourth thickness is not less than 0.5 nm and not more than 5 nm, andthe fifth thickness is not less than 4 nm and not more than 10 nm.
Configuration 6

The magnetic head according to any one of Configurations 3-5, whereina first non-magnetic layer thickness of the first non-magnetic layer in the first direction is not less than 1 nm and not more than 10 nm,a second non-magnetic layer thickness of the second non-magnetic layer in the first direction is not less than 0.5 nm and not more than 6 nm,a third non-magnetic layer thickness of the third non-magnetic layer in the first direction is not less than 0.5 nm and not more than 6 nm,a fourth non-magnetic layer thickness of the fourth non-magnetic layer in the first direction is not less than 1 nm and not more than 10 nm,a fifth non-magnetic layer thickness of the fifth non-magnetic layer in the first direction is not less than 0.5 nm and not more than 6 nm, anda sixth non-magnetic layer thickness of the sixth non-magnetic layer in the first direction is not less than 0.5 nm and not more than 6 nm or less.
Configuration 7

The magnetic head according to any one of Configurations 1-6, whereinone end of the magnetic element is electrically connected to the first magnetic pole,another end of the magnetic element is electrically connected to the second magnetic pole, anda differential electrical resistance of the magnetic element when a voltage between the first magnetic pole and the second magnetic pole is changed includes 3 or more peaks.
Configuration 8

A magnetic recording device, comprising:the magnetic head according to any one of Configurations 1-6; anda controller including an element circuit,one end of the magnetic element being electrically connected to the first magnetic pole,another end of the magnetic element being electrically connected to the second magnetic pole,the element circuit being configured to apply an element voltage between the first magnetic pole and the second magnetic pole,when the element voltage is applied, a potential of the first magnetic pole being lower than a potential of the second magnetic pole.
Configuration 9

The magnetic recording device according to Configuration 8, whereina differential electrical resistance of the magnetic element when changing a voltage between the first magnetic pole and the second magnetic pole includes a first peak, a second peak and a third peak,the voltage corresponding to the first peak is a first voltage,the voltage corresponding to the second peak is a second voltage,the voltage corresponding to the third peak is a third voltage,the second voltage is between the first voltage and the third voltage, andthe element voltage is equal to or higher than the third voltage.
Configuration 10

The magnetic recording device according to Configuration 8, whereina differential electrical resistance of the magnetic element when changing a voltage between the first magnetic pole and the second magnetic pole includes a first negative peak, a first positive peak and a second positive peak,the voltage corresponding to the first negative peak is a first negative peak voltage,the voltage corresponding to the first positive peak is a first positive peak voltage,the voltage corresponding to the second positive peak is a second positive peak voltage,the first positive peak voltage is between the first negative peak voltage and the second positive peak voltage, andthe element voltage is equal to or higher than the second positive peak voltage.

According to the embodiments, it is possible to provide a magnetic head and a magnetic recording device capable of improving the recording density.

Hereinabove, exemplary embodiments of the invention are described with reference to specific examples. However, the embodiments of the invention are not limited to these specific examples. For example, one skilled in the art may similarly practice the invention by appropriately selecting specific configurations of components included in magnetic heads and magnetic recording devices such as magnetic poles, magnetic elements, magnetic layers, non-magnetic layers, terminals, controllers, etc., from known art. Such practice is included in the scope of the invention to the extent that similar effects thereto are obtained.

Moreover, all magnetic heads and magnetic recording devices practicable by an appropriate design modification by one skilled in the art based on the magnetic heads and the magnetic recording devices described above as embodiments of the invention also are within the scope of the invention to the extent that the purport of the invention is included.