Patent ID: 12190917

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 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, and a fifth non-magnetic layer provided between the fourth magnetic layer and the fifth magnetic layer. The fourth magnetic layer includes a first element and at least one of Fe, Co or Ni. The first element including at least one selected from the group consisting of Cr, V, Mn, Ti, N and Sc. The fourth non-magnetic layer including at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The fifth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

Various embodiments are described below with reference to the accompanying drawings.

The drawings are schematic and conceptual; and the relationships between the thickness and width of portions, the proportions of sizes among portions, etc., are not necessarily the same as the actual values. The dimensions and proportions may be illustrated differently among drawings, even for identical portions.

In the specification and drawings, components similar to those described previously or illustrated in an antecedent drawing are marked with like reference numerals, and a detailed description is omitted as appropriate.

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 head130and 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 head130.

The magnetic head130includes a first magnetic pole31, a second magnetic pole32and a magnetic element20. The magnetic head130may 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 head130may 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 head130is 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 head130move relatively along the down-track direction. A recording magnetic field generated by a magnetic head130is 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 head130may 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 head130, 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 value 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, in the magnetic head130, the magnetic element20includes a first magnetic layer21, a second magnetic layer22, a third magnetic layer23, a fourth magnetic layer24, a first non-magnetic layer41, a second non-magnetic layer42, a third non-magnetic layer43, a fourth non-magnetic layer44and a fifth non-magnetic layer45.

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 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 second magnetic pole32.

In the embodiment, the fourth magnetic layer includes at least one of Fe, Co or Ni, and a first element including at least one selected from the group consisting of Cr, V, Mn, Ti, N and Sc. The fourth non-magnetic layer44includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The fifth non-magnetic layer45includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

The fourth magnetic layer has, for example, negative polarization. On the other hand, the first magnetic layer21, the second magnetic layer22and the third magnetic layer23include at least one of Fe, Co or Ni. The first magnetic layer21, the second magnetic layer22and the third magnetic layer23do not include the first element. Alternatively, a concentration of the first element in the first magnetic layer21, the second magnetic layer22and the third magnetic layer23is lower than a concentration of the first element in the fourth magnetic layer24. For example, the first magnetic layer21, the second magnetic layer22and the third magnetic layer23have positive polarization.

The fourth non-magnetic layer44contacts the fourth magnetic layer24. The fifth non-magnetic layer45contacts the fourth magnetic layer24and the second magnetic pole32.

The magnetization of the magnetic pole (e.g., the second magnetic pole32) is not always stable and may oscillate. Even if the magnetization of the second magnetic pole32is unstable, it is preferable that stable oscillation be obtained in the magnetic element20. In the magnetic head130according to the embodiment, by the magnetic element20including the fourth magnetic layer24, stable oscillation can be obtained even when the magnetization of the second magnetic pole32is unstable.

For example, non-magnetic layer (the fourth non-magnetic layer44and the fifth non-magnetic layer45) is provided on both sides of the fourth magnetic layer24. Thereby, the spin torque of the fourth magnetic layer24acts on the second magnetic pole32. For example, the magnetization32M of the second magnetic pole32is easily stabilized. For example, the orientation of the component of the magnetization24M of the fourth magnetic layer24along the first direction D1is opposite to the orientation of the component of the magnetization32M of the second magnetic pole32along the first direction D1.

For example, spin torque of the fourth magnetic layer24acts on the third magnetic layer23. Thereby, the magnetization23M of the third magnetic layer23becomes easy to oscillate. A high oscillation efficiency is obtained in the third magnetic layer23. According to the magnetic element20in the magnetic head130, 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.

FIGS.4A and4Bare schematic plan views illustrating magnetic heads of reference examples.

FIG.4Ashows a magnetic head139aof a reference example.FIG.4Bshows a magnetic head139bof a reference example. In the magnetic heads139aand139b, the fourth magnetic layer24does not include the first element (at least one selected from the group consisting of Cr, V, Mn, Ti, N and Sc). The spin torque of the fourth magnetic layer24acts on the second magnetic pole32in the magnetic head139a. In the magnetic head139a, the fifth non-magnetic layer45includes Cu. The spin torque of the fourth magnetic layer24does not act on the second magnetic pole32in the magnetic head139b. In the magnetic head139b, the fifth non-magnetic layer45includes Ru.

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

FIG.5illustrates simulation results of the characteristics of the magnetic heads130,139aand139b. In the simulation model, the magnetization of the second magnetic pole32is movable. 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 Po1. The higher the oscillation parameter Po1, the higher the intensity of stable oscillation.

As shown inFIG.5, in the region where the applied voltage Vs1is high, the oscillation parameter Po1of the magnetic head130is higher than the oscillation parameter Po1of the magnetic heads139aand139bof the reference example. Similar tendencies are obtained when the thicknesses of the magnetic layers are changed in the configuration of the magnetic heads139aand139b. In the configuration of the magnetic head130, high intensity oscillation can be obtained. According to the embodiments, it is possible to provide a magnetic head capable of improving the recording density.

In the magnetic head130, the first non-magnetic layer41includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W. The second non-magnetic layer42includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The third non-magnetic layer43includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W.

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.

In the magnetic head130, the second thickness t22is thicker than the first thickness t21. The third thickness t23is thicker than the first thickness t21. The fourth thickness t24is thinner than the third thickness t23. The second thickness t22is thinner than the fourth thickness t24.

In the magnetic head130, for example, the second magnetic layer22and the third magnetic layer23function as oscillation layers. The first magnetic layer21and the fourth magnetic layer24function as spin injection layers.

As shown inFIG.2, when the magnetic head130is in operation, an 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 element current ic flows in the direction from the first magnetic pole31to the second magnetic pole32. The element current ic flows in the direction from fifth non-magnetic layer45to first non-magnetic layer41. An element voltage Ve1is applied to the magnetic element20in the operation. The potential of the first magnetic pole31is lower than the potential of the second magnetic pole32when the element voltage Ve1is applied.

In the magnetic head130, for example, the orientation of the component of the magnetization24M of the fourth magnetic layer24along the first direction D1is opposite to the orientation of the component of the magnetization32M of the second magnetic pole32along the first direction D1. The orientation of the component of the magnetization21M of the first magnetic layer21along the first direction D1is the same as the orientation of the component of the magnetization24M of the fourth magnetic layer24along the first direction D1. The magnetization22M of the second magnetic layer22oscillates. The magnetization23M of the third magnetic layer23oscillates.

FIG.6is a schematic plan view illustrating a magnetic head according to the first embodiment.

As shown inFIG.6, in a magnetic head130aaccording to the embodiment, the relationship between the first thickness t21and the second thickness t22is different from that in the magnetic head130. Other configurations of the magnetic head130aare the same as the configurations of the magnetic head130.

In the magnetic head130a, the first thickness t21is thicker than the second thickness t22. The third thickness t23is thicker than the second thickness t22. The fourth thickness t24is thinner than the third thickness t23. High-intensity oscillation is also obtained in the magnetic head130a.

FIG.7is a schematic plan view illustrating a magnetic head according to the first embodiment.

As shown inFIG.7, in a magnetic head131according to the embodiment, the magnetic element20further includes a fifth magnetic layer25with magnetization25M and a sixth non-magnetic layer46. Other configurations of the magnetic head131may be the same as the configurations of the magnetic head130.

In the magnetic head131, the fifth magnetic layer25is provided between the third non-magnetic layer43and the third magnetic layer23. The sixth non-magnetic layer46is provided between the fifth magnetic layer25and the third magnetic layer23. In this example, the fifth magnetic layer25contacts the third non-magnetic layer43. The sixth non-magnetic layer46contacts the fifth magnetic layer25and the third magnetic layer23.

In the magnetic head131, the first non-magnetic layer41includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W. The second non-magnetic layer42includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The third non-magnetic layer43includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W. The sixth non-magnetic layer46includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

A thickness of the fifth magnetic layer25in the first direction D1is defined as a fifth thickness t25. In the magnetic head130, the second thickness t22is thicker than the first thickness t21. The third thickness t23is thicker than the first thickness t21. The fourth thickness t24is thinner than the third thickness t23. The fifth thickness t25is thinner than the third thickness t23.

FIG.8is a schematic plan view illustrating a magnetic head of a reference example.

As shown inFIG.8, in the magnetic head139cof the reference example, the fourth magnetic layer24and the fifth non-magnetic layer45are not provided. The fourth non-magnetic layer44includes Ru. Other configurations are the same as the configurations of the magnetic head131.

FIG.9is a graph illustrating characteristics of the magnetic heads.

FIG.9illustrates simulation results of the characteristics of the magnetic heads131and139c. In the simulation model, the magnetization of the second magnetic pole32is movable. As shown inFIG.9, the oscillation parameter Po1of the magnetic head131is higher than the oscillation parameter Po1of the magnetic head139cof the reference example. Similar tendencies are obtained when the thicknesses of the magnetic layers are changed in the structure of the magnetic head139c. In the configuration of the magnetic head131, high-intensity oscillation can be obtained.

FIG.10is a schematic plan view illustrating a magnetic head according to the first embodiment.

As shown inFIG.10, in a magnetic head131aaccording to the embodiment, the relationship between the first thickness t21and the second thickness t22is different from that in the magnetic head131. Other configurations of the magnetic head131aare the same as the configurations of the magnetic head131. In the configuration of the magnetic head131a, high-intensity oscillation is also obtained.

In the magnetic head131a, the first non-magnetic layer41includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W. The second non-magnetic layer42includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The third non-magnetic layer43includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W. The sixth non-magnetic layer46includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag.

In the magnetic head131a, the first thickness t21is thicker than the second thickness t22. The third thickness t23is thicker than the second thickness t22. The fourth thickness t24is thinner than the third thickness t23. The fifth thickness t25is thinner than the third thickness t23.

FIG.11is a schematic plan view illustrating a magnetic head according to the first embodiment.

As shown inFIG.11, in the magnetic head131baccording to the embodiment, the materials of the third non-magnetic layer43and the sixth non-magnetic layer46are different from the materials of the third non-magnetic layer43and the sixth non-magnetic layer46in the magnetic head131. Other than this, the configuration of the magnetic head131ais the same as the configuration of the magnetic head131. In the configuration of the magnetic head131a, high intensity oscillation is also obtained.

In the magnetic head131b, the first non-magnetic layer41includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W. The second non-magnetic layer42includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The third non-magnetic layer43includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The sixth non-magnetic layer46includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W.

In the magnetic head131b, the second thickness t22is thicker than the first thickness t21. The third thickness t23is thicker than the first thickness t21. The fourth thickness t24is thinner than the third thickness t23. The fifth thickness t25is thinner than the third thickness t23.

FIG.12is a schematic plan view illustrating a magnetic head according to the first embodiment.

As shown inFIG.12, in a magnetic head132according to the embodiment, the magnetic element20further includes a sixth magnetic layer26with magnetization26M and a seventh non-magnetic layer47. Other configurations of the magnetic head132may be the same as the configurations of the magnetic head131. In the configuration of the magnetic head132, high-intensity oscillation is also obtained.

In the magnetic head132, the sixth magnetic layer26is provided between the third non-magnetic layer43and the fifth magnetic layer25. The seventh non-magnetic layer47is provided between the sixth magnetic layer26and the fifth magnetic layer25.

In the magnetic head132, the first non-magnetic layer41includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W. The second non-magnetic layer42includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The third non-magnetic layer43includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The sixth non-magnetic layer46includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag. The seventh non-magnetic layer47includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W.

A thickness of the sixth magnetic layer26in the first direction D1is defined as a sixth thickness t26. In the magnetic head132, the second thickness t22is thicker than the first thickness t21. The third thickness t23is thicker than the first thickness t21. The fourth thickness t24is thinner than the third thickness t23. The fifth thickness t25is thinner than the third thickness t23. The sixth thickness t26is thinner than the second thickness t22.

In the embodiment, as shown inFIG.12, 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 nonmagnetic layer thickness t45. A thickness of the sixth non-magnetic layer46in the first direction D1is defined as a sixth non-magnetic layer thickness t46. A thickness of the seventh non-magnetic layer47in the first direction D1is defined as a seventh non-magnetic layer thickness t47.

In the embodiment, 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 0.5 nm and not more than 6 nm. The fifth non-magnetic 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. The seventh non-magnetic layer thickness t47may be, for example, not less than 1 nm and not more than 10 nm.

In the operation, the element current ic greater than or equal to the threshold value is supplied to the magnetic element20. The element voltage Ve1is applied to the magnetic element20in the operation. 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. In the magnetic heads130,130a,131,131a,131band132, the potential of the first magnetic pole31is lower than the potential of the second magnetic pole32when the element voltage Ve1is applied.

FIGS.13to18are graphs illustrating characteristics of the magnetic heads.

These figures illustrate a differential electrical resistance of the magnetic element20when a voltage Va1applied to the magnetic element20is changed. The horizontal axis is the voltage Va1. The vertical axis is the differential electrical resistance Rd1. The voltage Va1may be the voltage between the first terminal T1and the second terminal T2. For example, a voltage corresponding to voltage Va1is applied to the magnetic element20.FIGS.13-18correspond to magnetic heads130,130a,131,131a,131band132.

As shown inFIG.13, in the magnetic head130, the differential electrical resistance Rd1includes a first positive bottom b1and a first positive peak p1. The first positive bottom b1is, for example, a negative peak. The voltage Va1corresponding to the first positive bottom b1is a first positive bottom voltage Vb1. The voltage Va1corresponding to the first positive peak p1is a first positive peak voltage Vp1. The first positive bottom voltage Vb1, the first positive peak voltage Vp1, and the element voltage Ve1are positive. The potential of the first magnetic pole31is lower than the potential of the second magnetic pole32when the voltage Va1being positive is applied. In this example, the first positive peak voltage Vp1is higher than the first positive bottom voltage Vb1. The first positive peak voltage Vp1may be lower than the first positive bottom voltage Vb1. The element voltage Ve1is higher than the first positive peak voltage Vp1and higher than the first positive bottom voltage Vb1.

Thus, the differential electrical resistance Rd1includes at least one peak and at least one bottom. In this example, the at least one peak is the first positive peak p1. At least one bottom is the first positive bottom b1. It is considered that the peaks and bottoms correspond to discontinuous changes in electrical resistance accompanying reversal of magnetization of multiple magnetic layers included in the magnetic element20.

The voltage Va1corresponding to at least one peak is the peak voltage (in this example, the first positive peak voltage Vp1). The voltage Va1corresponding to at least one bottom is the bottom voltage (in this example, the first positive bottom voltage Vb1). The element voltage Ve1is higher than the peak voltage and higher than the bottom voltage. Thereby, stable and high-intensity oscillation can be obtained.

As shown inFIG.14, in the magnetic head130a, the differential electrical resistance Rd1includes a first negative peak n1and the first positive bottom b1. The voltage Va1corresponding to the first negative peak n1is a first negative peak voltage Vn1. The first negative peak voltage Vn1is negative. The potential of the first magnetic pole31is higher than the potential of the second magnetic pole32when the negative voltage Va1is applied. The element voltage Ve1is higher than the peak voltage (first negative peak voltage Vn1) and higher than the bottom voltage (first positive bottom voltage Vb1). A stable and high-intensity oscillation can be obtained.

As shown inFIG.15, in the magnetic head131, the differential electrical resistance Rd1includes the first positive bottom b1, the first positive peak p1and a second positive peak p2. The voltage Va1corresponding to the second positive peak p2is a second positive peak voltage Vp2. The first positive bottom voltage Vb1, the first positive peak voltage Vp1and the second positive peak voltage Vp2are positive. The element voltage Ve1is higher than the peak voltage (the first positive peak voltage Vp1and the second positive peak voltage Vp2) and higher than the bottom voltage (the first positive bottom voltage Vb1). A stable and high-intensity oscillation can be obtained.

As shown inFIG.16, in the magnetic head131a, the differential electrical resistance Rd1includes the first negative peak n1, the first positive bottom b1and the first positive peak p1. The element voltage Ve1is higher than the peak voltage (first negative peak voltage Vn1and first positive peak voltage Vp1) and higher than the bottom voltage (first positive bottom voltage Vb1). A stable and high-intensity oscillation can be obtained.

As shown inFIG.17, in the magnetic head131b, the differential electrical resistance Rd1includes the first negative peak n1, the first positive bottom b1and the first positive peak p1. The element voltage Ve1is higher than the peak voltage (first negative peak voltage Vn1and first positive peak voltage Vp1) and higher than the bottom voltage (first positive bottom voltage Vb1). A stable and high-intensity oscillation can be obtained.

As shown inFIG.18, in the magnetic head132, the differential electrical resistance Rd1includes the first negative peak n1, the first positive bottom b1, the first positive peak p1and the second positive peak p2. The element voltage Ve1is higher than the peak voltages (first negative peak voltage Vn1, first positive peak voltage Vp1, and second positive peak voltage Vp2) and higher than the bottom voltage (first positive bottom voltage Vb1). A stable and high-intensity oscillation can be obtained.

In the magnetic heads130,130a,131,131a,131b, and132, the absolute value of the element voltage Ve1is 10 times or less the absolute value of the peak voltage, which is the reference for setting the element voltage Ve1. The absolute value of the element voltage Ve1is 10 times or less the absolute value of the bottom voltage, which is the reference for setting the element voltage Ve1. The absolute value of the element voltage Ve1may be 8 times or less of the absolute value of the peak voltage, which is the reference for setting the element voltage Ve1. The absolute value of the element voltage Ve1may be eight times or less of the absolute value of the bottom voltage, which is the reference for setting the element voltage Ve1.

In embodiments, the tail of one peak may overlap the adjacent peak. The tail of one peak may overlap one bottom. The tail of one bottom may overlap adjacent peaks. The tail of one bottom may overlap adjacent bottom.

In the magnetic heads131,131a,131b, and132, the absolute value of the peak voltage, which is the reference for setting the element voltage Ve1, may be 4 times or less than the absolute value of the other peak voltages. The absolute value of the above peak voltage, which is the reference for setting the element voltage Ve1, may be 3 times or less the absolute value of the other peak voltages.

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 head130is 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.19is a schematic perspective view illustrating the magnetic recording device according to the embodiment.

As shown inFIG.19, the magnetic head (for example, the magnetic head130) according to the embodiment is used together with the magnetic recording medium80. In this example, the magnetic head130includes a recording section60and a reproducing section70. Information is recorded on the magnetic recording medium80by the recording section60of the magnetic head130. 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.19, the magnetic recording medium80moves relative to the magnetic head130in a direction of medium movement85. Information corresponding to the magnetization83of the magnetic recording layer81is controlled at an arbitrary position by the magnetic head130. Information corresponding to the magnetization83of the magnetic recording layer81is reproduced at an arbitrary position by the magnetic head130.

FIG.20is a schematic perspective view illustrating a part of the magnetic recording device according to the embodiment.

FIG.20illustrates a head slider.

The magnetic head130is 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 head130is arranged on the side surface of the air outflow side159B of the head slider159or the like. As a result, the magnetic head130moves relative to the magnetic recording medium while flying above or in contact with the magnetic recording medium.

FIG.21is a schematic perspective view illustrating the magnetic recording device according to the embodiment.

FIGS.22A and22Bare schematic perspective views illustrating a part of the magnetic recording device according to the embodiment.

As shown inFIG.21, 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.22Ais an enlarged perspective view of the head stack assembly160, illustrating the configuration of a part of the magnetic recording device.

FIG.22Bis a perspective view illustrating the magnetic head assembly (head gimbal assembly: HGA)158that forms part of the head stack assembly160.

As shown inFIG.22A, 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.22B, 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).

Configuration 1

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 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, anda fifth non-magnetic layer provided between the fourth magnetic layer and the fifth magnetic layer,the fourth magnetic layer including a first element and at least one of Fe, Co or Ni, the first element including at least one selected from the group consisting of Cr, V, Mn, Ti, N and Sc,the fourth non-magnetic layer including at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag, andthe fifth 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 magnetic layer, the second magnetic layer and the third magnetic layer include at least one of Fe, Co or Ni, andthe first magnetic layer, the second magnetic layer, and the third magnetic layer do not include the first element, or a concentration of the first element in the first magnetic layer, the second magnetic layer, and the third magnetic layer is lower than a concentration of the first element in the fourth magnetic layer.

Configuration 3

The magnetic head according to Configuration 2, whereinthe fourth non-magnetic layer contacts the fourth magnetic layer, andthe fifth non-magnetic layer contacts the fourth magnetic layer and the second magnetic pole.

Configuration 4

The magnetic head according to Configuration 3, 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, andthe third non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W.

Configuration 5

The magnetic head according to Configuration 4, 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,a third thickness of the third magnetic layer in the first direction is thicker than the first thickness, anda fourth thickness of the fourth magnetic layer in the first direction is thinner than the third thickness.

Configuration 6

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

Configuration 7

The magnetic head according to Configuration 3, whereinthe magnetic element further includes a fifth magnetic layer and a sixth non-magnetic layer,the fifth magnetic layer is provided between the third non-magnetic layer and the third magnetic layer, andthe sixth non-magnetic layer is provided between the fifth magnetic layer and the third magnetic layer.

Configuration 8

The magnetic head according to Configuration 7, 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 sixth non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W,a 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,a third thickness of the third magnetic layer in the first direction is thicker than the first thickness,a fourth thickness of the fourth magnetic layer in the first direction is thinner than the third thickness, anda fifth thickness of the fifth magnetic layer in the first direction is thinner than the third thickness.

Configuration 9

The magnetic head according to Configuration 7, 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 Ru, Ir, Ta, Rh, Pd, Pt and W,the sixth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,a first thickness of the first magnetic layer in a first direction from the first magnetic pole to the second magnetic pole is thicker than a second thickness of the second magnetic layer in the first direction,a third thickness of the third magnetic layer in the first direction is thicker than the second thickness,a fourth thickness of the fourth magnetic layer in the first direction is thinner than the third thickness, anda fifth thickness of the fifth magnetic layer in the first direction is thinner than the third thickness.

Configuration 10

The magnetic head according to Configuration 7, 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 Ru, Ir, Ta, Rh, Pd, Pt and W,the sixth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,a 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,a third thickness of the third magnetic layer in the first direction is thicker than the first thickness,a fourth thickness of the fourth magnetic layer in the first direction is thinner than the third thickness, andthe fifth thickness of the fifth magnetic layer in the first direction is thinner than the third thickness.

Configuration 11

The magnetic head according to Configuration 7, whereinthe magnetic element further includes a sixth magnetic layer and a seventh non-magnetic layer,the sixth magnetic layer is provided between the third non-magnetic layer and the fifth magnetic layer, andthe seventh non-magnetic layer is provided between the sixth magnetic layer and the fifth magnetic layer.

Configuration 12

The magnetic head according to Configuration 11, 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 sixth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,the seventh non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W,a 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,a third thickness of the third magnetic layer in the first direction is thicker than the first thickness,a fourth thickness of the fourth magnetic layer in the first direction is thinner than the third thickness,a fifth thickness of the fifth magnetic layer in the first direction is thinner than the third thickness, anda sixth thickness of the sixth magnetic layer in the first direction is thinner than the second thickness.

Configuration 13

The magnetic head according to any one of Configurations 1-12, 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 changing a voltage between the first magnetic pole and the second magnetic pole includes at least one peak and at least one bottom.

Configuration 14

A magnetic recording device, comprising:the magnetic head according to any one of Configurations 1-12; 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 being applied, a potential of the first magnetic pole being lower than a potential of the second magnetic pole.

Configuration 15

The magnetic recording device according to Configuration 14, whereina differential electrical resistance of the magnetic element when a voltage between the first magnetic pole and the second magnetic pole is changed includes at least one peak and at least one bottom,the voltage corresponding to the at least one peak is a peak voltage,the voltage corresponding to the at least one bottom is a bottom voltage, andthe element voltage is higher than the peak voltage and higher than the bottom voltage.

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

In the specification of the application, “perpendicular” and “parallel” refer to not only strictly perpendicular and strictly parallel but also include, for example, the fluctuation due to manufacturing processes, etc. It is sufficient to be substantially perpendicular and substantially parallel.

Hereinabove, exemplary embodiments of the invention are described with reference to specific examples. However, the embodiments of the invention are not limited to these specific examples. For example, one skilled in the art may similarly practice the invention by appropriately selecting specific configurations of components included in magnetic heads 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.

Further, any two or more components of the specific examples may be combined within the extent of technical feasibility and are included in the scope of the invention to the extent that the purport of the invention is included.

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

Various other variations and modifications can be conceived by those skilled in the art within the spirit of the invention, and it is understood that such variations and modifications are also encompassed within the scope of the invention.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.