Spin-orbit torque layer and hybrid non-local spin valve read sensor

Abstract

To provide a magnetic recording head including a read head with high signal output for use in a magnetic recording device.SOLUTION: A read head 500 includes a sensor 540 disposed on a media facing surface (MFS) and a spin generator 550 disposed away from the sensor and recessed from the MFS. The sensor and the spin generator are disposed on a non-magnetic layer 406. The sensor includes a free layer, and the spin generator includes at least one spin-orbit-torque (SOT) layer 510. The SOT layer is configured from a topological material such as BiSb. The sensor detects a read signal by using a first voltage lead line V+ and a second voltage lead line V-. The spin generator is configured to inject a spin current into the sensor via the non-magnetic layer by using a first current lead line I+ and a second current lead line I-. The shape of the non-magnetic layer is triangular or trapezoidal to further concentrate the spin current.SELECTED DRAWING: Figure 5A-5B

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 521,819, filed June 19, 2023, and is incorporated herein by reference.

[0002] Background of the disclosure TECHNICAL FIELD Embodiments of the present disclosure relate generally to magnetic recording heads, including read heads, for magnetic media drives or hard disk drives and the like. [Background technology]

[0003] 2. Description of Related Art The heart of a computer is the hard disk drive. Information is written to and read from the disk as it rotates past read and write heads placed very close to the disk's magnetic surface. Various read head designs have been proposed to increase linear density based on different physical mechanisms, including the Tunneling Magneto-Resistive (TMR) effect, Giant Magneto Resistive (GMR) effect, Extraordinary Magneto-Resistive (EMR) effect, Spin Torque Oscillator (STO) effect, and Non-Localized Spin Valve (NLSV) effect.

[0004] In an NLSV design, the read head may include two spatially separated tunnel junction structures, one of which is recessed from the media facing surface (MFS) and the other tunnel junction structure is located at the MFS. The recessed structure often includes a pinned layer with fixed magnetization for spin injection and a ferromagnetic layer. However, the read signal output in such a read head is limited by the spin injection efficiency from the pinned layer, which has a spin polarization less than unity. Thus, the relatively low spin current injection efficiency results in poor signal output, adversely affecting the read head's ability to accurately read data.

[0005] Thus, there is a need in the art for improved read heads having high signal output for use in magnetic recording devices. Summary of the Invention

[0006] The present disclosure generally relates to a magnetic recording head including a read head. The read head includes a sensor disposed at a medium facing surface (MFS) and a spin generator spaced from the sensor and recessed from the MFS. The sensor and spin generator are disposed above a non-magnetic layer. The sensor includes a free layer and the spin generator includes at least one Spin Orbit Torque (SOT) layer. The SOT layer may be constructed of BiSb. The sensor is configured to detect a read signal using a first voltage lead and a second voltage lead. The spin generator is configured to inject a spin current into the sensor through the non-magnetic layer using a first current lead and a second current lead. The shape of the non-magnetic layer is triangular or trapezoidal to further concentrate the spin current.

[0007] In one embodiment, the read head includes a sensor including a first shield, a second shield, a non-magnetic layer disposed between the first and second shields, a free layer disposed at a medium facing surface (MFS) between the non-magnetic layer and the second shield, and a spin generator adjacent to the non-magnetic layer and recessed a first distance from the MFS. The spin generator is spaced from the sensor and includes a spin-orbit torque (SOT) layer. The first distance is greater than a height of the free layer measured from the MFS.

[0008] In another embodiment, a read head of a magnetic recording device includes a first shield including a shield notch, a second shield, a non-magnetic layer disposed between the shield notch and the second shield, a sensor including a free layer disposed at a medium facing surface (MFS) between the non-magnetic layer and the second shield, and a spin generator recessed from the MFS, the spin generator including a first spin-orbit torque (SOT) layer disposed between the first shield and the non-magnetic layer, and a second SOT layer disposed between the non-magnetic layer and the second shield.

[0009] In yet another embodiment, a read head of a magnetic recording device includes a first shield, a second shield, a non-magnetic layer disposed between the first and second shields, a sensor including a first free layer and a second free layer disposed between the first and second shields at a medium facing surface (MFS), and a spin generator remote from the MFS, the spin generator including a first spin-orbit torque (SOT) layer disposed between the first shield and the non-magnetic layer, and a second SOT layer disposed between the non-magnetic layer and the second shield. [Brief description of the drawings]

[0010] So that the above-mentioned features of the present disclosure may be understood in detail, a more particular description of the present disclosure briefly summarized above can be had by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only typical embodiments of the present disclosure, and therefore should not be considered as limiting the scope of the present disclosure, since other equally effective embodiments may be recognized. [Figure 1] FIG. 1 is a diagram illustrating a hard disk drive embodying the present disclosure. [Diagram 2] FIG. 2 is a fragmentary cross-sectional side view through the center of a read / write head facing a magnetic medium, according to one embodiment. [Diagram 3] FIG. 3 shows a prior art NLSV based read head. [Figure 4A-4B] 4A-4B show a read head according to one embodiment. [Fig. 4C-4D] 4C-4D show a read head according to another embodiment. [Figure 5A-5B] 5A-5B are diagrams illustrating a read head of a magnetic recording head according to one embodiment. [Fig. 5C-5D] 5C-5D are diagrams illustrating a read head of a magnetic recording head according to another embodiment. [Figure 6A-6B] 6A-6B are diagrams illustrating a read head of a magnetic recording head according to yet another embodiment. [Figure 6C-6D] 6C-6D are diagrams illustrating a read head of a magnetic recording head according to one embodiment. [Figure 7A-7B] 7A-7B are diagrams illustrating a read head of a magnetic recording head according to another embodiment. [Figure 7C-7D] 7C-7D are diagrams illustrating a read head of a magnetic recording head according to yet another embodiment. [Figure 8A-8B] 8A-8B are diagrams illustrating a read head of a magnetic recording head according to another embodiment. [Fig. 8C-8D]8C-8D are diagrams illustrating a read head of a magnetic recording head according to one embodiment. [Figure 9A-9B] 9A-9B are diagrams showing a read head of a magnetic recording head according to yet another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] To facilitate understanding, the same reference numerals have been used whenever possible to designate identical elements common to the figures. Elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

[0012] Detailed explanation In the following, reference will be made to embodiments of the present disclosure. However, it should be understood that the present disclosure is not limited to the specific described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, is intended to implement and practice the present disclosure. Furthermore, the embodiments of the present disclosure may achieve advantages over other possible solutions and / or over the prior art, but whether or not a particular advantage is achieved by a given embodiment does not limit the present disclosure. Thus, the following aspects, features, embodiments and advantages are merely illustrative and are not considered elements or limitations of the appended claims unless expressly recited in the claim(s). Similarly, reference to "the present disclosure" is not to be construed as a generalization of any inventive subject matter disclosed herein, and is not to be considered elements or limitations of the appended claims unless expressly recited in the claims.

[0013] The present disclosure generally relates to a magnetic recording head including a read head. The read head comprises a sensor disposed at a medium facing surface (MFS) and a spin generator spaced apart from the sensor and spaced apart from the MFS. The sensor and spin generator are disposed on a non-magnetic layer. The sensor comprises a free layer and the spin generator comprises at least one spin-orbit torque (SOT) layer. The SOT layer may be comprised of BiSb. The sensor is configured to detect a read signal using a first voltage lead and a second voltage lead. The spin generator is configured to inject a spin current into the sensor through the non-magnetic layer using a first current lead and a second current lead. The shape of the non-magnetic layer is triangular or trapezoidal to further concentrate the spin current.

[0014] FIG. 1 is a schematic diagram of a magnetic recording device 100 according to one embodiment. The magnetic recording device 100 includes a magnetic recording head, such as a write head. The magnetic recording device 100 is a magnetic media drive, such as a hard disk drive (HDD). Such a magnetic media drive may be a single drive / device or may include multiple drives / devices. For ease of illustration, a single disk drive is shown as the magnetic recording device 100 in the implementation shown in FIG. The magnetic recording device 100 (e.g., a disk drive) includes at least one rotatable magnetic disk 112 supported on a spindle 114 and rotated by a drive motor 118. The magnetic recording on each rotatable magnetic disk 112 is in the form of any suitable pattern of data tracks, such as an annular pattern of concentric data tracks on the rotatable magnetic disk 112.

[0015] At least one slider 113 is disposed proximate to the rotatable magnetic disk 112. Each slider 113 supports a head assembly 121. The head assembly 121 includes one or more magnetic recording heads (e.g., read / write heads), such as a write head including a spintronics device. As the rotatable magnetic disk 112 rotates, the slider 113 moves radially in and out over the disk surface 122 so that the head assembly 121 can access different tracks on the rotatable magnetic disk 112 where desired data is written. Each slider 113 is attached to an actuator arm 119 via a suspension 115. The suspension 115 provides a slight spring force that biases the slider 113 toward the disk surface 122. Each actuator arm 119 is attached to an actuator 127. The actuator 127 shown in FIG. 1 may be a voice coil motor (VCM). The VCM comprises a coil movable within a fixed magnetic field, with the direction and speed of coil movement controlled by motor current signals provided by a control unit 129 .

[0016] Head assembly 121, such as a write head of head assembly 121, includes a media facing surface (MFS), such as an air bearing surface (ABS), that faces disk surface 122. During operation of magnetic recording device 100, rotation of rotatable magnetic disk 112 creates an air or gas bearing between slider 113 and disk surface 122, which exerts an upward force or lift on slider 113. In this manner, the air or gas bearing counters the slight spring force of suspension 115 and supports slider 113 slightly above and off disk surface 122 by a small, substantially constant spacing during operation.

[0017] Each component of the magnetic recording device 100 is controlled by control signals generated by a control unit 129, such as access control signals and internal clock signals. The control unit 129 includes a logic control circuit, a storage means, and a microprocessor. The control unit 129 generates control signals for controlling various system operations, such as drive motor control signals on line 123, head position and seek control signals on line 128. The control signals on line 128 provide desired current profiles to optimally move and position the slider 113 to a desired data track on the rotatable magnetic disk 112. Write and read signals are communicated to and from the head assembly 121 by a recording channel 125. An embodiment can be combined with other embodiments, and the magnetic recording device 100 can further include multiple media, or disks, multiple actuators, and / or multiple sliders.

[0018] Figure 2 is a schematic diagram of a cross-sectional side view of a head assembly 200 facing the rotatable magnetic disk 112 or other magnetic storage medium shown in Figure 1, according to one embodiment. Head assembly 200 can correspond to head assembly 121 described in Figure 1. Head assembly 200 includes an MFS 212, such as an ABS, facing the rotatable magnetic disk 112. As shown in Figure 2, the rotatable magnetic disk 112 moves relatively in the direction indicated by arrow 232, and head assembly 200 moves relatively in the direction indicated by arrow 234.

[0019] One embodiment may be combined with other embodiments, head assembly 200 includes magnetic read head 211. Magnetic read head 211 may include sensing element 204 disposed between shields S1 and S2. Sensing element 204 and related structures are further described with respect to various embodiments shown in this disclosure. Magnetic fields of magnetized regions in rotatable magnetic disk 112, such as perpendicularly recorded bits or longitudinally recorded bits, are detectable by sensing element 204 as recorded bits.

[0020] The head assembly 200 includes a write head 210. In one embodiment, which may be combined with other embodiments, the write head 210 includes a main pole 220, a leading shield 206, a trailing shield (TS) 240, and a spintronics device 250 disposed between the main pole 220 and the TS 240. Each of the main pole 220, the spintronics device 250, the leading shield 206, and the TS 240 has a front portion at the MFS.

[0021] The main pole 220 includes a magnetic material such as CoFe, CoFeNi, NiFe, or FeNiRe, or other suitable magnetic material. An embodiment may be combined with other embodiments, in which the main pole 220 includes small grains of a randomly textured magnetic material, such as a body-centered cubic (BCC) material formed with a random texture. In one example, the random texture of the main pole 220 is formed by plating. The write head 210 includes a coil 218 around the main pole 220 that energizes the main pole 220 to generate a write magnetic field to affect the magnetic recording medium of the rotatable magnetic disk 112. The coil 218 may be a spiral structure or one or more sets of pancake structures.

[0022] An embodiment may be combined with other embodiments, where the main pole 220 includes a trailing taper 242 and a leading taper 244. The trailing taper 242 extends from a position set back from the MFS 212 toward the MFS 212. The leading taper 244 extends from a position set back from the MFS 212 toward the MFS 212. The trailing taper 242 and the leading taper 244 may have the same degree of taper or different degrees of taper relative to the longitudinal axis 260 of the main pole 220. An embodiment may be combined with other embodiments, where the main pole 220 does not include the trailing taper 242 and the leading taper 244. In such an embodiment, the main pole 220 includes a trailing side and a leading side, where the trailing side and the leading side are substantially parallel.

[0023] The TS 240 includes a magnetic material such as FeNi or other suitable magnetic material and serves as a second pole and a return pole for the main pole 220. The leading shield 206 may provide electromagnetic shielding functionality and is separated from the main pole 220 by a leading gap 254.

[0024] 3 shows a prior art read head 300 using NLSV. The read head 300 includes a read sensor 340 disposed in an MFS adjacent to the medium 301 and a spin generator 350 recessed from the MFS. The read sensor 340 and the spin generator 350 are disposed and separated between a first shield (not shown) and a second shield (not shown), respectively, such that the read sensor 340 is exposed to the MFS and the spin generator 350 is recessed from the MFS. The read sensor 340 and the spin generator 350 are separated from each other by a finite distance. A non-magnetic layer 306 is disposed adjacent to each of the sensor 340 and the spin generator 350. The non-magnetic layer 306 may be made of, for example, Al.

[0025] The read sensor 340 includes a first free layer 344 and a first tunnel barrier layer 342 disposed between the first free layer 344 and the non-magnetic layer 306. Voltage leads are connected to the non-magnetic layer 306 and the first free layer 344 for detecting read signals through the read sensor 340.

[0026] The spin generator 350 includes a reference layer 336, a cap layer 332 disposed on the reference layer 336, and a second magnetic (FM) layer 334 disposed between the non-magnetic layer 306 and the second tunnel barrier layer 332. The spin generator 350 is spaced from the read sensor 340 by a distance equal to the spin diffusion length of the non-magnetic layer 306. For example, if the non-magnetic layer 306 is made of Cu, the distance can be from about 100 nm to about 300 nm. Current leads are connected to the non-magnetic layer 306 and the reference layer 336. In operation, when a current is applied and forced through the spin generator 350, a spin current travels from the spin generator 350 through the non-magnetic layer 306 to the read sensor 340. Spin injection causes a spin current to flow through the read sensor 340, enabling signal detection from magnetization changes in the first free layer 344 during data reading.

[0027] However, because the spin generator 350 includes a reference layer 336 with a fixed magnetization direction, the spin injection efficiency is limited by the spin polarization of the reference layer 336 (which is less than about 1), and as such, the read signal output of the read head 300 is limited.

[0028] 4A-4B show a read head 400 according to one embodiment. FIG. 4A shows a cross-sectional view of the read head 400, and FIG. 4B shows a top view of the read head 400. The read head 400 may be within the read head 211 of FIG. 2. The read head 400 may be part of the magnetic recording device 100 of FIG. 1. In the top view of FIG. 4B, the first shield (S1) 402 and the second shield (S2) 404 are not shown for clarity. The first shield 402 may be S1 of FIG. 2, and the second shield 404 may be S2 of FIG. 2.

[0029] The read head 400 includes a read sensor 440 disposed at the MFS and a spin generator 450 recessed from the MFS. The read sensor 440 is disposed between a first shield 402 and a second shield 404. A non-magnetic spin transport layer 406 is disposed between the second shield 404 and between the read sensor 440 and the spin generator 450. The non-magnetic layer 406 extends from the MFS to the back end of the spin generator 450 and may have the same height from the MFS as the first and second shields 402, 404.

[0030] In some embodiments, the non-magnetic layer 406 can have a height greater than the first and second shields 402, 404 or a height less than the first and second shields 402, 404 (the configuration shown in FIG. 4A). The non-magnetic layer 406 has a height 452 less than or close to the spin diffusion length of the non-magnetic layer 406, typically about 100 nm to about 300 nm, depending on the material used for the non-magnetic layer 406. The non-magnetic layer 406 can be made of Cu, Al, or other 2D materials such as graphene, and MoS 2 , HfS 2 The read sensor 440 may be constructed of materials with long spin diffusion lengths, such as other van der Waals materials such as ZnO, ZnS, ZnO ...

[0031] Depending on (1) the respective heights of the first shield 402 and the second shield 404, and (2) the spin diffusion properties of the non-magnetic layer 406 (which affect the setback distance of the spin generator 450), the spin generator 450 may or may not be between the two shields. Although FIGS. 4A-9B show one or more spin generators between the shields, and the shields are relatively similar or of the same dimensions, the disclosure is not so limited and other embodiments exist in which the spin generator 450 may not be between the two shields. In those embodiments, a portion of the non-magnetic layer 406 that overlaps the sensor may be between the two shields, but another portion of the non-magnetic layer 406 that overlaps the spin generator 450 may not be between the two shields.

[0032] The read sensor 440 includes a free layer 418 disposed adjacent to the first shield 402 and a tunnel barrier layer 442 disposed between the free layer 418 and the nonmagnetic layer 406. The free layer 418 may be comprised of a magnetic material such as one or more layers of Co-Fe, Co-Fe-B, Pt, or a Heusler alloy. The tunnel barrier layer 442 may be comprised of, for example, MgO or AlOx (where x is a number greater than 1). Voltage leads are connected to the first and second shields 402, 404 for detecting a read signal via the read sensor 440.

[0033] The spin generator 450 is a multi-layer structure. The spin generator 450, or separate read sensor 450, refers to any of the read sensors 500-900 described below in Figures 5A-9B. Current leads are connected to the spin generator 450 for spin injection. In operation, when a current is applied in the plane of the spin generator 450 inside the read head 400, the spin Hall effect generates a spin current that flows across the spin generator 450 and into the non-magnetic layer 406. This spin current flows from the spin generator 450 through the non-magnetic layer 406 to the read sensor 440. This spin current through the read sensor 440 allows the generation of an electrical signal across the sensor 440 as the free layer 418 rotates its magnetization when reading data.

[0034] As shown in FIG. 4B, the non-magnetic layer 406 can have a triangular or trapezoidal shape that is wider as the non-magnetic layer 406 moves away from the MFS and narrower as the non-magnetic layer 406 moves closer to the MFS. In such an embodiment, the wide portion of the non-magnetic layer 406 has a width 454 of about 100 nm or less and the narrow portion of the non-magnetic layer 406 has a width 456 of about 10 nm to about 20 nm, which is close to the track width (TW) of the read sensor 440. The free layer 418 of the sensor 440 may have the same width 456 as the narrow portion of the non-magnetic layer 406. The spin generator 450 is located at the wider portion of the non-magnetic layer 406 if the width of the non-magnetic layer 406 changes. Side shields 448 are located on either side of the read sensor 440 at the MFS for proper biasing of the free layer 418.

[0035] 4C-4D show a read head 401 according to one embodiment. FIG. 4C shows a cross-sectional view of the read head 401, and FIG. 4D shows a top view of the read head 401. The read head 401 may be within the read head 211 of FIG. 2. The read head 401 may be part of the magnetic recording device 100 of FIG. 1. In the top view of FIG. 4D, the first shield (S1) 402 and the second shield (S2) 404 are not shown for clarity.

[0036] The read head 401 of Figures 4C-4D is similar to the read head 400 of Figures 4A-4B, except that the spin generator 450 performs the function of spin detection, referred to herein as the spin detector 450 or spin detection layer 450, and the current and voltage leads are reversed so that the generated spin current flows in the opposite direction through the non-magnetic layer 406. In the read head 401, an input current lead (I) is connected to the first shield 402 and the second shield 404, and a voltage lead (V) is connected to the spin detector 450. In operation, when a current is applied to the read head 401, a spin current (I s) flows across the read sensor 440 into the non-magnetic layer 406. The spin current flows from the read sensor 440 through the non-magnetic layer 406 to the spin detector 450. The perpendicular spin current through the spin detector 450 allows the generation of an electrical signal / voltage across the side (cross-track direction) of the spin detector 450 due to the inverse spin Hall effect. When the free layer 418 rotates its magnetization direction when reading data, the spin polarization (I s ) changes, resulting in an output voltage (V out ) reflects the magnetic bit information on the recording track.

[0037] Furthermore, when the current lead (I) is connected to the first shield 402 and the second shield 404 and the voltage lead (V) is connected to the spin detector 450, the non-magnetic layer 406 has a rectangular shape. In such an embodiment, the non-magnetic layer 406 has a consistent narrow width 456 of about 10 nm to about 20 nm, which is close to the track width (TW) of the read sensor 440.

[0038] 5A-9B show various embodiments of read heads 500, 501, 600, 601, 700, 701, 800, 801, 900, respectively, according to various embodiments. Each read head 500, 600, 700, 800, 900 may be individually the read head 400 of FIGS. 4A-4B. Each read head 501, 601, 701, 801 may be individually the read head 401 of FIGS. 4C-4D. Each read head 500, 501, 600, 601, 700, 701, 800, 801, 900 may be individually within the read head 211 of FIG. 2. Each read head 500, 501, 600, 601, 700, 701, 800, 801, 900 may be individually part of the magnetic recording device 100 of FIG. 1. The aspects of Figures 5A-9B may not be shown to scale, such as the height of the first and second shields 402, 404 in the X-direction. Additionally, the aspects of each read head 500, 501, 600, 601, 700, 701, 800, 801, 900 may be used in combination with each other and / or with the read head 400 of Figures 4A-4B and / or the read head 401 of Figures 4C-4D. As such, the various layers and / or aspects of the read head 400, 401, 500, 501, 600, 601, 700, 701, 800, 801, 900 may have consistent reference numerals.

[0039] 5A-5B are diagrams illustrating a read head 500 of a magnetic recording head according to one embodiment. Figure 5A shows a cross-sectional view of the read head 500, and Figure 5B shows an MFS view of the read head 500.

[0040] The read head 500 includes a first shield 402, a second shield 404, a non-magnetic layer 406, a read sensor 540 disposed in the MFS, and a spin generator or spin generating structure 550 recessed from the MFS. A notch 516 is disposed between the first shield 402 recessed from the MFS and the non-magnetic layer 406. The notch 516 may be recessed from the MFS by a distance of about 0 nm to about 20 nm. The notch 516 has a thickness in the Y direction of about 5 nm to about 20 nm and a height in the X direction of about 5 nm to about 20 nm. A dielectric layer 515 is recessed in front of the notch 516 at the MFS and from the MFS, and is disposed behind the notch 516. The dielectric layer 515 separates the first shield 402 from the non-magnetic layer 406. The dielectric layer 515 may be made of SiN, SiO 2 , MgO, AlO, AlN, or a combination thereof. The read sensor 540 includes a first tunnel barrier layer 520 disposed on the non-magnetic layer 406, a free layer 418 disposed on the first tunnel barrier layer 520, and a cap layer 522, which may be composed of a conductive material, disposed on the free layer 418 and in contact with the second shield 404. As shown in FIG. 5B, the spin-orbit torque (SOT) layer 510 has a larger overall size along the X and Z directions than the free layer 418. The magnetization (M) direction of the free layer 418 is in the -Z direction during operation, which is the same direction as the magnetization direction of the soft bias (SB) side shield 526.

[0041] As shown in FIG. 5A, the insulating layer 514 is recessed from the MFS behind the sensor 540. The spin generator 550 is disposed adjacent to the insulating layer 514. The spin generator 550 comprises a seed layer 508 disposed on the non-magnetic layer 406, an SOT layer 510 (in certain embodiments where the SOT layer is comprised of BiSb, it may be referred to herein as a BiSb layer 510) disposed on the seed layer 508, and a cap layer 512 disposed on the SOT layer 510. The cap layer 512 may be comprised of a non-magnetic, high resistivity material, such as, for example, Ru, NiFeGe, or some oxide material. In some embodiments, the insulating layer 514 extends over the cap layer 512 and behind the spin generator 550, as shown in FIG. 5A. The insulating layer 514 may be made of a material such as SiN, SiO 2 , MgO, AlO, ALN, or combinations thereof. As mentioned above, the first voltage lead (V - ) is connected to the first shield 402 and the second voltage lead (V + ) is connected to the second shield 404 for read signal detection across the first read sensor 540. The first shield 402, the second shield 404, and the notch 516 may each individually be constructed of a magnetic material similar to the soft bias material, such as, for example, NiFe, NiFe / CoFe stacks, NiFe / NiFeCr stacks, or NiFe / W stacks (where " / " refers to each layer in a multi-layer stack).

[0042] As shown in the MFS diagram of FIG. 5B, the read head 500 further comprises a first soft bias (SB) side shield 524 and a second SB side shield 526, respectively, adjacent the sensor 540. The first and second SB side shields 524, 526 may each be individually constructed from NiFe, CoFe, and other magnetic materials for proper free layer bias across the tracks (i.e., Z direction in FIG. 5B). A first current lead (I + ) and the second current lead (I -) is connected to the SOT layer 510 for spin injection. From FIG. 4A, a current flows through the SOT layer 510 into the page, i.e., in the Z direction. In operation, when this in-plane (in the plane of the SOT layer 510) current is applied to the read head 500, spin accumulation occurs, which results in the generation of spin current in the non-magnetic layer 406 due to the spin Hall effect. This spin current flows from the spin generator 550 through the non-magnetic layer 406 to the read sensor 540. This spin current flowing to the read sensor 540 enables the generation of an electrical signal across the sensor 540 as the free layer 418 rotates its magnetization when reading data.

[0043] The SOT layer 510 is composed of a heavy metal with strong spin-orbit coupling, such as Ta, Pt, W, or Hf. The SOT layer 510 may be composed of a topological insulating material, such as BiSe, WTe, YBiPt, or BiSb. The SOT layer 510 may be composed of BiSb with a (012) orientation. The SOT layer 510 may be composed of undoped BiSb or doped BiSbX, where the dopant is less than about at. 10%, and X is derived from an element that does not readily react with Bi, e.g., B, N, Al, Si, Ti, V, Cr, Fe, Ni, Cu, Ge, Y, Zr, Ru, Mo, Ag, Hf, Ta, W, or Ir, or an alloy combination with one or more of the aforementioned elements, such as CuAg, CuNi, RuGe, etc. More generally, some of the listed dopants can be used with other topological insulating materials besides BiSb. The SOT layer 510 has a Y-direction (e.g., down-track direction) thickness 558 of about 5 nm to about 20 nm, an X-direction height 560 (e.g., stripe height) of about 100 nm to about 1 μm, and a Z-direction width 562 (e.g., cross-track direction) of less than about 100 nm.

[0044] A number of materials are available as the seed layer 508 for growing a textured SOT layer 510 (012) using a textured (100) or amorphous seed layer. One group of materials, group A, includes V, V 3 Al, Mn 3 Al, Nb, Mo, W, Ta, WTi 50, body-centered cubic (BCC), such as NiAl, RhAl, or alloy combinations of these materials with similar lattice constants, or Cr (heated above about 250°C), RuAl, IrAl, CoAl, B2 phase, NiAl-B2 phase, CrMo (Mo is about 20-50 at.%) or B2 phase, A2CrX (X is about 10 at.%, heated above about 250°C, and selected from Ru, Ti, W, and Mo).

[0045] Group A materials provide texturing for subsequent layers and are sometimes called MgO(100) textured layer stacks. Generally speaking, deposition of a boron-affinity element or alloy, such as an alloy of tantalum, tungsten, or titanium, followed by deposition of a boron-containing magnetic layer results in the formation of an amorphous magnetic layer material, such as cobalt iron boron or cobalt boron, but the boron is extracted leaving a magnetic cobalt iron or cobalt layer. On top of that layer, MgO can be formed with a (100) texture. Other methods of making MgO(100) include growing heated chromium or ruthenium aluminum in a textured form. MgO(100) textured layer stacks can also be fabricated by depositing a magnetic boron alloy of CoFeB or CoB on a thin high-B gettering alloy seed layer of Hf, Ta, W, Ti, or alloys containing these elements, followed by a magnetic bilayer of Co or CoFe and a thin layer of MgO.

[0046] Another material group B includes face-centered cubic (FCC) oxide materials such as FeO, CoO, NiO, ZrO, MgO, TiO, MgTiO, and MnO. Another material group C includes ScN, TiN, NbN, ZrN, HfN, TaN, VN, CrN, ScC, TiC, NbC, ZrC, HfC, TaC, WC, VC, and W. 0.8 Zr 0.2 Group C materials include FCC nitrides and carbides such as C. Depending on deposition conditions, group C materials can be deposited as amorphous to nanocrystalline thin films. The resistivity of group C materials is in the range of 100-200 μΩ cm.

[0047] Another group, D, is Fe 2 Val, Cr 2 CoAl, CoTiSb, Mn 2 VSi, V 2 Al, [Mn 0.5 Co 0.5 ] 2 VAl, [Mn 0.75 Co 0.25 ] 2 VSi, CoMnNbAl, CoZrFeAl, Ti 2 Group E includes non-magnetic Heusler materials such as MnAl. 2 MnSb, CoFeX, NiFeX, (X is one or more of Si, Al, Mn, and Ge.) CoFe, NiFe, Co 2 MnGe, CoMnSb, NiMnSb, Co 2 FeGe, Co 2 MnSn, Co 2 The other group, group F, is made up of amorphous non-magnetic highly resistive electrical shunt block layers that do not promote strong (012) BiSbX texture or growth. These are SiO 2 , Al 2 O 3 , SiN, AlN, SiC, SiCrOx, NiX, FeX, and CoX, where X can be one or more of these elements including Fe, Co, Ni, Ta, Hf, W, Ir, Pt, Ti, Zr, N, Ru, Ge, and / or B.

[0048] Another group, G, includes metallic or ceramic amorphous materials with nearest neighbor X-ray diffraction peaks in the d-spacing range of 2.19 Å to 2.02 Å. Such materials include the non-magnetic and magnetic materials of groups A, D, or E, which are layered or alloyed with one or more of the elements Cu, Ag, Ge, Al, Mg, Si, Mn, Ni, Co, Mo, Zr, Y, Bi, Hf, Ta, W, Ir, Pt, Ti, or B. These effectively form non-magnetic amorphous layers, producing amorphous materials, or starting with an amorphous material such as a-Ge, a-NiPX alloys (X is one of Ru, Rh, Y, Zr, Mo, Hf, Ta, W, Re, Pt, or Ir). Group G also includes a-Ge, a-NiP and amorphous / nanocrystalline alloys with one or more elements of Cu, Ag, Ge, Al, Mg, Si, Mn, Ni, Co, Mo, Zr, Y, Bi, Hf, Ta, W, Ir, Pt, Ti, or B that promote a strong BiSb(012) texture.

[0049] Yet another group, H, is high perpendicular magnetic anisotropy (PMA) materials, which can be amorphous or crystalline materials. Amorphous rare earth transition metals (RE-TM) with high PMA, such as TbFeCo, TbFeB, Nd, Pr, Sm(Fe,Co)B, or heavy metals, such as CoZrTaB, can be used. Multilayer polycrystalline stacks of Co / Pt, Co / Pd, CoFe / Pt, Co / Tb, or CoFe / Tb (" / " indicates layer separation), or single layer PMA materials with high Ku, such as CoPt, CoPtCr, CoFePt, and FePt, can be used with an amorphous high spin polarization layer next to the spin Hall layer for (012) texture growth.

[0050] Figures 5C-5D show a read head 501 of a magnetic recording head according to one embodiment. Figure 5C shows a cross-sectional view of the read head 501, and Figure 5D shows an MFS view of the read head 501. In the read head 501, the non-magnetic layer 406 may be rectangular as shown in Figures 4A-4D and described above.

[0051] The read head 501 is similar to the read head 500 of FIGS. 5A-5B, except that the current and voltage leads are reversed. In the read head 501, a first current lead (I + ) is connected to the second shield 404 and the second current lead (I - ) is connected to the first shield 402. The first voltage lead (V - ) and the second voltage lead (V + ) is connected to the SOT layer 510 for read signal detection via the spin detector 550.

[0052] From FIG. 5C, a current flows through the read sensor 540 and the non-magnetic layer 406 in the X-direction. In operation, when a current is applied to the read head 501, spin accumulation occurs, and thus spin current is injected from the free layer 418 into the non-magnetic layer 406, generating a spin current along the non-magnetic layer 406. The spin current travels through the non-magnetic layer 406 across the read sensor 540 to the spin detector 550, where the spin current flows out of plane (i.e., in the Y-direction) through the SOT layer 510. The spin current flowing through the spin detector 550 enables the generation of an electrical signal across the SOT layer 510 along the Z-direction as the free layer 418 rotates its magnetization direction when reading data.

[0053] 6A-6B are diagrams illustrating a read head 600 of a magnetic recording head according to another embodiment, in which FIG 6A illustrates a cross-sectional view of the read head 600 and FIG 6B illustrates an MFS view of the read head 600.

[0054] 5A-5B, except that the read head 600 does not include a notch 516. Rather, a dielectric layer 515 extends between the first shield 402 and the non-magnetic layer 406. Additionally, a first voltage lead (V - ) is connected to the back surface of the nonmagnetic layer 406 instead of the first shield 402.

[0055] Figures 6C-6D show a read head 601 of a magnetic recording head according to one embodiment. Figure 6C shows a cross-sectional view of the read head 601, and Figure 6D shows an MFS diagram of the read head 601. In the read head 601, the non-magnetic layer 406 may be rectangular as shown in Figures 4A-4D and described above.

[0056] Read head 601 is similar to read head 600 of FIGS. 6A-6B, except that the current and voltage leads are reversed. In read head 601, a first current lead (I + ) is connected to the second shield 404 and the second current lead (I - ) is connected to the spin injection nonmagnetic layer 406. The first voltage lead (V - ) and the second voltage lead (V + ) is connected to the SOT layer 510 for read signal detection via the spin detector 650.

[0057] In operation, when a current is applied to the read head 601, spin accumulation occurs, which generates a spin current that flows from the sensor 640 into the non-magnetic layer 406. The spin current travels through the non-magnetic layer 406 across the read sensor 640 to the spin detector 650, where the spin current flows out of the plane (i.e., in the Y direction) through the SOT layer 510. The spin current flowing in the spin detector 650 enables the generation of an electrical signal across the SOT layer 510 due to the inverse spin Hall effect as the free layer 418 rotates its magnetization orientation when reading data.

[0058] Figures 7A-7B show a read head 700 of a magnetic recording head according to yet another embodiment. Figure 7A shows a cross-sectional view of the read head 700, and Figure 7B shows an MFS view of the read head 700. The read head 700 is similar to the read head 500 of Figures 5A-5B, except that the sensor 740 and spin generator 750 of the read head 700 are misaligned in both the X and Y directions.

[0059] In the read head 700, a spin generator 750 is disposed above the first shield 402. The spin generator 750 is set back from the MFS by a shield notch 702. The shield notch 702 can be considered part of the first shield 402. The shield notch 702 may be composed of the same material as the first shield 402 and / or the notch 516. A first insulating layer 715 is disposed between the shield notch 702 and the spin generator 750. The first insulating layer 715 may also extend between the first shield 402 and the seed layer 508. The notch 516 is disposed above the shield notch 702. A non-magnetic layer 406 is disposed above the notch 516, the spin generator 750, and the first insulating layer 715. A sensor 740 is disposed above the non-magnetic layer 406 in the MFS. The second insulating layer 714 is disposed on the nonmagnetic layer 406 behind the sensor 740. Portions of the first and second insulating layers 715, 714 may be exposed at the MFS, as shown in FIG. 7B, and each may be individually composed of the same material as the insulating layer 514. The first SB-side shield 524 and the second SB-side shield 526 are disposed adjacent to the sensor 740 at the MFS.

[0060] Negative voltage lead (V - ) is connected to the first shield 402, and the positive voltage lead (V + ) is connected to the second shield 404. The negative current lead (I - ) and positive current lead (I +) is connected to the SOT layer 510 for spin injection. A current flows through the SOT layer 510 in the page (with respect to FIG. 5A), i.e., in the Z direction. In operation, when this in-plane (in the plane of the SOT layer 510) current is applied to the read head 700, spin accumulation occurs, and thus a spin current is generated in the non-magnetic layer 406 due to the spin Hall effect. This spin current flows from the spin generator 750 through the non-magnetic layer 406 to the read sensor 740. This spin current flowing to the read sensor 740 enables the generation of an electrical signal across the sensor 740 as the free layer 418 rotates its magnetization when reading data.

[0061] Figures 7C-7D are diagrams illustrating a read head 701 of a magnetic recording head according to one embodiment. Figure 7C illustrates a cross-sectional view of the read head 701, and Figure 7D illustrates an MFS diagram of the read head 701. In the read head 701, the non-magnetic layer 406 may be rectangular as shown in Figures 4A-4D and described above.

[0062] Read head 701 is similar to read head 700 of FIGS. 7A-7B, except that the current and voltage leads are reversed. In read head 701, a first current lead (I + ) is connected to the second shield 404 and the second current lead (I - ) is connected to the first shield 402 for spin injection. The first voltage lead (V - ) and the second voltage lead (V + ) is connected to the SOT layer 510 for read signal detection via the spin detector 750.

[0063] In operation, when a current is applied to the read head 701, spin accumulation occurs, causing a spin current to emerge from the sensor 740 and flow into the non-magnetic layer 406. The spin current travels through the non-magnetic layer 406 across the read sensor 740 to the spin detector 750, where the spin current flows out of plane (i.e., in the Y direction) through the SOT layer 510. The spin current flowing in the spin detector 750 enables the generation of an electrical signal across the SOT layer 510 due to the inverse spin Hall effect as the free layer 418 rotates its magnetization orientation when reading data.

[0064] 8A-8B illustrate a read head 800 of a magnetic recording head according to another embodiment. Figure 8A illustrates a cross-sectional view of the read head 800, and Figure 8B illustrates an MFS view of the read head 800. The read head 800 is similar to the read head 500 of Figures 5A-5B, except that the read head 800 includes a second seed layer 808, a second SOT layer 810, and a second cap layer 812.

[0065] In the read head 800, the first shield 402 further comprises a shield notch 802 disposed at the MFS between the first shield 402 and the notch 516. The shield notch 802 may be composed of the same material as the first shield 402. A second cap layer 812 is disposed on the first shield 402 behind the shield notch 802, a second SOT layer 810 is disposed on the second cap layer 812, and a second seed layer 808 is disposed on the second SOT layer 810. The second cap layer 812 may be composed of the same material as the cap layer 512. A non-magnetic layer 406 is disposed on the second seed layer 808. A second insulating layer 814 is disposed between the shield notch 802 and the second cap layer 812, the second SOT layer 810, and the second seed layer 808. The second insulating layer 814, similar to the insulating layer 514, may be disposed between the first shield 402 and the second cap layer 812 and behind the second cap layer 812, the second SOT layer 810, and the second seed layer 808. The second insulating layer 814 may be composed of the same material as the first insulating layer 514. The second SOT layer 810 has the same dimensions as the first SOT layer 510 (i.e., the same dimensions as the SOT layer 510 of FIGS. 5A-7B).

[0066] A first seed layer 508 is disposed on the non-magnetic layer 406, a first SOT layer 510 is disposed on the first seed layer 508, and a first cap layer 512 is disposed on the first SOT layer 510. A second shield 404 is disposed on the first cap layer 512. The first cap layer 512 may be comprised of the same material as the second cap layer 812, the first SOT layer 510 may be comprised of the same material as the second SOT layer 810, and the first seed layer 508 may be comprised of the same material as the second seed layer 808. The first cap layer 512, the first SOT layer 510, the first seed layer 508, a portion of the non-magnetic layer 406 disposed in contact with the first seed layer 508, the second seed layer 808, the second SOT layer 810, and the second cap layer 812 collectively form a spin generator 850.

[0067] First signal voltage lead (V -) is connected to the shield notch 802 and the second signal voltage lead (V + ) is connected to the second shield 404. The first negative current lead (I 1- ) and the first positive current lead (I 1+ ) is connected to the second SOT layer 810, and the second negative current lead (I 2- ) and the second positive current lead (I 2+ ) is connected to the first SOT layer 510. The first negative current lead (I 1- ) is the second positive current lead (I 2+ ) and the first positive current lead (I 1+ ) is the second negative current lead (I 2- During operation, a first current (I 1 ) flows through the second SOT layer 810 out of the page (with respect to FIG. 8A), i.e., in the Z direction, resulting in a second current (I 2 ) flows through the first SOT layer 510 into the page (with respect to FIG. 8A ), i.e., in the −Z direction. By including two SOT layers on either side of the non-magnetic layer 406, the amount of spin current generated from the spin generator 850, and therefore into the non-magnetic layer 406, is doubled.

[0068] Figures 8C-8D are diagrams illustrating a read head 801 of a magnetic recording head according to one embodiment. Figure 8C illustrates a cross-sectional view of the read head 801, and Figure 8D illustrates an MFS diagram of the read head 801. In the read head 801, the non-magnetic layer 406 may be rectangular as shown in Figures 4A-4D and described above.

[0069] Read head 801 is similar to read head 800 of FIGS. 8A-8B, except that the current and voltage leads are reversed. In read head 801, a first input current lead (I + ) is connected to the second shield 404 and the second input current lead (I - ) is connected to the shield notch 802 for spin injection. The first negative voltage lead (V 1- ) and the first positive voltage lead (V 1+) is connected to the second SOT layer 810 and the second negative voltage lead (V 2- ) and the second positive voltage lead (V 2+ ) is connected to the first SOT layer 510 for read signal detection via the spin detector 850. A first positive voltage lead (V 1+ ) is the second negative voltage lead (V 2- ) and the first negative voltage lead (V 1- ) is the second positive voltage lead (V 2+ ) adjacent to the first positive voltage lead (V 1+ ) and the second negative voltage lead (V 2- ) indicates that the final signal readout is from the first negative voltage lead (V 1- ) and the second positive voltage lead (V 2+ ) are connected as in

[0070] In operation, when an input current is applied to the read head 801, spin accumulation occurs, causing a spin current to be generated from the sensor 840 and flow into the non-magnetic layer 406. The spin current travels across the read sensor 840, through the non-magnetic layer 406, and to the spin detector 850. The spin current is then split such that half the spin current flows down through the second SOT layer 810 and half the spin current flows up through the first SOT layer 510 (I s 8D ) and the voltage lead V in FIG. 8D . The spin current flows out of plane (i.e., in the Y direction) through each SOT layer 510, 810. The perpendicular spin current flowing through the SOT layers 510, 810 enables the generation of an electrical signal across the SOT layers 510, 810 via the inverse spin Hall effect when the free layer 418 rotates its magnetization orientation when reading data. Since the two split spin currents flow in opposite directions in the Y direction, the voltage lead V in FIG. 8D 2+ / V 2- and V 1+ / V 1- The signal polarity generated is also reversed, as shown in Figure 1. The first positive voltage lead (V 1+ ) and the second negative voltage lead (V 2- ) indicates that the final signal is connected to the first negative voltage lead (V 1-) and the second positive voltage lead (V 2+ ) are connected together.

[0071] 9A-9B illustrate a read head 900 of a magnetic recording head according to yet another embodiment. FIG. 9A illustrates a cross-sectional view of the read head 900, and FIG. 9B illustrates an MFS view of the read head 900. The read head 900 is similar to the read head 800 of FIGS. 8A-8B, but does not include the shield notch 802, and the sensor 940 includes a first free layer 418 and a second free layer 918 for a Dual Free Layer (DFL) configuration. Additionally, similar to the read heads 600 and 700 of FIGS. 6A-7B, the read head 900 does not include the notch 516.

[0072] In the read head 900, the sensor 940 includes a seed layer 920 disposed on the first shield 402, a second free layer 918 disposed on the seed layer 920, a second tunnel barrier layer 922 disposed on the second free layer 918, a first tunnel barrier layer 520 disposed on the non-magnetic layer 406, the first free layer 418 disposed on the first tunnel barrier layer 520, and a cap layer 522 disposed on the first free layer 418. The second tunnel barrier layer 922 and a portion of the non-magnetic layer 406 disposed in contact with the first tunnel barrier layer 520 may also be considered part of the sensor 940. The second free layer 918 may be composed of the same material as the first free layer 418.

[0073] The second insulating layer 914 is disposed below the non-magnetic layer 406 between the sensor 940 and the spin generator 950. The second insulating layer 914 may be disposed between the second cap layer 812 and the first shield 402, and behind the second cap layer 812, the second SOT layer 810, and the second seed layer 808. The second insulating layer 914 can be composed of the same material as the insulating layer 514. The first and second tunnel barrier layers 520, 922 may each be composed of the same material. The seed layer 920 and the cap layer 522 may be composed of the same material.

[0074] The first and second SB-side shields 524, 526 are disposed adjacent to the first free layer 418 in the MFS. The third SB-side shield 924 and the fourth SB-side shield 926 are disposed adjacent to the second free layer 918 in the MFS. The first, second, third and fourth SB-side shields 524, 526, 924, 926 can all be made of the same material. The first SB-side shield 524 is disposed above the third SB-side shield 924, and the second SB-side shield 526 is disposed above the fourth SB-side shield 926. The first Ru layer 925 is disposed between the first SB-side shield 524 and the third SB-side shield 924, and the second Ru layer 927 is disposed between the second SB-side shield 526 and the fourth SB-side shield 926. The first Ru layer 925 is tuned to enable antiferromagnetic coupling of the first and third SB-side shields 524, 924, and the second Ru layer 927 is tuned to enable antiferromagnetic coupling of the second and fourth SB-side shields 526, 926. The magnetizations of the third and fourth SB-side shields 924, 926 relative to the magnetizations of the first and second SB-side shields 524, 526 are opposite such that the first free layer 418 and the second free layer 918 have opposite magnetization orientations in the cross-track direction (along the Z direction).

[0075] First signal voltage lead (V - ) is connected to the first shield 402 and the second signal voltage lead (V + ) is connected to the second shield 404. The first negative current lead (I 1- ) and the first positive current lead (I 1+ ) is connected to the second SOT layer 810, and the second negative current lead (I 2- ) and the second positive current lead (I 2+ ) is connected to the first SOT layer 510. The first negative current lead (I 1- ) is the second positive current lead (I 2+ ) and the first positive current lead (I 1+ ) is the second negative current lead (I 2- ) is placed next to it.

[0076] During operation, the first current (I 1 ) flows through the second SOT layer 810 to the outside of the page (with respect to FIG. 9A), i.e., in the Z direction, resulting in a second current (I 2 ) flows through the first SOT layer 510 towards the inside of the page (with respect to FIG. 9A), i.e., in the −Z direction. The magnetization direction of the second free layer 918 is in the Z direction, and the magnetization direction of the first free layer 418 is in the −Z direction. Thus, the first free layer 418 and the second free layer 918 have antiparallel magnetization directions. By including two SOT layers in the spin generator 950, the spin current is doubled. The signal coming from each free layer 418, 918 is determined by the relative angle between the magnetization of the free layer and the spin polarization (P) of the nonmagnetic layer 406. By including two free layers 418, 918 in the sensor 940, the generated signal is doubled.

[0077] By including at least one SOT layer in the read sensor away from the MFS, the above-described read head can achieve higher spin current injection / polarization by increasing the effective spin injection efficiency significantly above 1. Additionally, the trapezoidal shape of the non-magnetic transport layer allows for better concentration of the spin current, increasing the signal output at the read sensor located at the MFS.

[0078] In one embodiment, the read head includes a first shield, a second shield, a non-magnetic layer disposed between the first and second shields, a sensor including a free layer disposed between the non-magnetic layer and the second shield at a medium facing surface (MFS), and a spin generator disposed adjacent to the non-magnetic layer and recessed a first distance from the MFS, the spin generator including a spin-orbit torque (SOT) layer, the first distance being greater than a height of the free layer measured from the MFS.

[0079] The spin generator is disposed between the non-magnetic layer and the second shield. The read head further comprises a negative voltage lead connected to the first shield, a positive voltage lead connected to the second shield, a positive current lead connected to the SOT layer, and a negative current lead connected to the SOT layer, the positive and negative current leads being aligned to provide a current path through the SOT layer in the cross-track direction. The read head further comprises a negative voltage lead connected to the non-magnetic layer, a positive voltage lead connected to the second shield, a positive current lead connected to the SOT layer, and a negative current lead connected to the SOT layer, the positive and negative current leads being aligned to provide a current path through the SOT layer in the cross-track direction.

[0080] The read head further comprises a negative current lead connected to the first shield, a positive current lead connected to the second shield, a positive voltage lead connected to the SOT layer, and a negative voltage lead connected to the SOT layer. The read head further comprises a negative current lead connected to the non-magnetic layer, a positive current lead connected to the second shield, a positive voltage lead connected to the SOT layer, and a negative voltage lead connected to the SOT layer. The SOT layer comprises a topological insulating material. The topological insulating material is BiSb. The non-magnetic layer comprises a first portion and a second portion, the first portion having a greater width than the second portion, the first portion being disposed adjacent to the spin generator, and the second portion being disposed adjacent to the sensor. The spin generator further comprises a seed layer disposed on the non-magnetic layer and a cap layer disposed on the SOT layer. The sensor further comprises a first tunnel barrier layer disposed on the non-magnetic layer and a cap layer disposed on the free layer. The spin generator is disposed between the non-magnetic layer and the first shield. The magnetic recording head includes a read head. The magnetic recording device includes a magnetic recording head.

[0081] In another embodiment, a magnetic recording device includes a read head including a first shield including a shield notch, a second shield, a non-magnetic layer disposed between the shield notch and the second shield, a sensor including a free layer disposed at a medium facing surface (MFS) between the non-magnetic layer and the second shield, and a spin generator recessed from the MFS, the spin generator including a first spin-orbit torque (SOT) layer disposed between the first shield and the non-magnetic layer, and a second SOT layer disposed between the non-magnetic layer and the second shield.

[0082] The first SOT layer is disposed adjacent to the shield notch and the second SOT layer is disposed adjacent to the free layer. The non-magnetic layer extends between the sensor and the spin generator and has a height of about 100 nm to about 300 nm. The read head further includes a first negative current lead connected to the first SOT layer, a first positive current lead connected to the first SOT layer, a second positive current lead connected to the second SOT layer and disposed adjacent to the first negative current lead, and a second negative current lead connected to the second SOT layer and disposed adjacent to the first positive current lead.

[0083] The read head further comprises a first negative voltage lead connected to the first SOT layer, a first positive voltage lead connected to the first SOT layer, a second positive voltage lead connected to the second SOT layer and disposed adjacent to the first negative voltage lead, and a second negative voltage lead connected to the second SOT layer and disposed adjacent to the first positive voltage lead. The read head further comprises a non-magnetic notch disposed between the shield notch and the non-magnetic layer. The spin generator is disposed between the first shield and the second shield. The magnetic recording device comprises a magnetic recording head.

[0084] In yet another embodiment, a magnetic recording device includes a read head including a first shield, a second shield, a non-magnetic layer disposed between the first and second shields, a sensor including a first free layer and a second free layer disposed between the first and second shields at a medium facing surface (MFS), and a spin generator recessed from the MFS, the spin generator including a first spin-orbit torque (SOT) layer disposed between the first shield and the non-magnetic layer, and a second SOT layer disposed between the non-magnetic layer and the second shield.

[0085] The read head further comprises a first negative current lead connected to the first SOT layer, a first positive current lead connected to the first SOT layer, a second positive current lead connected to the second SOT layer and positioned adjacent to the first negative current lead, a second negative current lead connected to the second SOT layer and positioned adjacent to the first positive current lead, The read head further comprises a first negative voltage lead connected to the first SOT layer, a first positive voltage lead connected to the first SOT layer, a second positive voltage lead connected to the second SOT layer and positioned adjacent to the first negative voltage lead, and a second negative voltage lead connected to the second SOT layer and positioned adjacent to the first positive voltage lead.

[0086] The first free layer is disposed between the first shield and the non-magnetic layer, and the second free layer is disposed between the non-magnetic layer and the second shield. The read head further comprises a first soft-bias side shield disposed adjacent to the first free layer at the MFS, a second soft-bias side shield disposed adjacent to the first free layer at the MFS, a third soft-bias side shield disposed adjacent to the second free layer at the MFS, a fourth soft-bias side shield disposed adjacent to the second free layer at the MFS, a first Ru layer disposed between the first soft-bias side shield and the third soft-bias side shield, and a second Ru layer disposed between the second soft-bias side shield and the fourth soft-bias side shield. The first free layer is separated from the first SOT layer by a first insulating layer, and the second free layer is separated from the second SOT layer by a second insulating layer. The first SOT layer and the second SOT layer each individually have a thickness of about 5 nm to about 20 nm, a height of about 100 nm to about 1 μm, and a width of less than about 100 nm. The non-magnetic layer extends between the sensor and the spin generator, the non-magnetic layer has a height of about 100 nm to about 300 nm, the non-magnetic includes a first portion and a second portion, the first portion has a width greater than the second portion, the first portion is disposed adjacent to the spin generator, and the second portion is disposed adjacent to the sensor. The spin generator is disposed between the first shield and the second shield. The magnetic recording device includes a magnetic recording head.

[0087] While the forgoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof, which scope is determined by the claims which follow.

Claims

1. A first shield; A second shield; and a nonmagnetic layer disposed between the first shield and the second shield; a sensor including a free layer disposed between the nonmagnetic layer and the second shield at a media facing surface (MFS); a spin generator disposed adjacent to the nonmagnetic layer and recessed a first distance from the MFS; the spin generator is remote from the sensor and includes a Spin Orbit Torque (SOT) layer; the first distance is greater than a height of the free layer as measured from the MFS; Read head.

2. the spin generator is disposed between the nonmagnetic layer and the second shield.

2. The read head of claim 1.

3. a negative voltage lead connected to the first shield; a positive voltage lead connected to the second shield; a positive current lead connected to the SOT layer; a negative current lead connected to the SOT layer, the positive current lead and the negative current lead are aligned to provide a current path through the SOT layer in a cross-track direction.

2. The read head of claim 1.

4. a negative voltage lead connected to the nonmagnetic layer; a positive voltage lead connected to the second shield; a positive current lead connected to the SOT layer; a negative current lead connected to the SOT layer, the positive current lead and the negative current lead are aligned to provide a current path through the SOT layer in a cross-track direction.

2. The read head of claim 1.

5. a negative current lead connected to the first shield; a positive current lead connected to the second shield; a positive voltage lead connected to the SOT layer; a negative voltage lead connected to the SOT layer; 2. The read head of claim 1.

6. a negative current lead connected to the nonmagnetic layer; a positive current lead connected to the second shield; a positive voltage lead connected to the SOT layer; a negative voltage lead connected to the SOT layer; 2. The read head of claim 1.

7. The SOT layer includes a topological insulating material.

2. The read head of claim 1.

8. The topological insulating material is BiSb.

8. A read head as claimed in claim 7.

9. the nonmagnetic layer includes a first portion and a second portion; the first portion has a width greater than the second portion; the first portion is disposed adjacent to the spin generator; The second portion is disposed adjacent to the sensor.

2. The read head of claim 1.

10. the spin generator further includes a seed layer disposed on the nonmagnetic layer and a cap layer disposed on the SOT layer; the sensor further includes a first tunnel barrier layer disposed over the nonmagnetic layer and a cap layer disposed over the free layer.

2. The read head of claim 1.

11. the spin generator is disposed between the nonmagnetic layer and the first shield.

2. The read head of claim 1.

12. A read head according to claim 1, Magnetic recording head.

13. A magnetic recording head comprising: Magnetic recording device.

14. A read head is provided, The read head comprises: a first shield including a shield notch; A second shield; and a nonmagnetic layer disposed between the shield notch and the second shield; a sensor including a free layer disposed between the nonmagnetic layer and the second shield at a media facing surface (MFS); a spin generator disposed back from the MFS and spaced from the sensor; the spin generator includes a first spin orbit torque (SOT) layer disposed between the first shield and the nonmagnetic layer, and a second SOT layer disposed between the nonmagnetic layer and the second shield. Magnetic recording head.

15. the first SOT layer is disposed adjacent to the shield notch; the second SOT layer is disposed adjacent to the free layer; The magnetic recording head of claim 14.

16. the non-magnetic layer extends between the sensor and the spin generator and has a height of 100 nm to 300 nm; The magnetic recording head of claim 14.

17. The read head comprises: a first negative current lead connected to the first SOT layer; a first positive current lead connected to the first SOT layer; a second positive current lead connected to the second SOT layer and disposed adjacent to the first negative current lead; a second negative current lead connected to the second SOT layer and disposed adjacent to the first positive current lead; The magnetic recording head of claim 14.

18. The read head comprises: a first negative voltage lead connected to the first SOT layer; a first positive voltage lead connected to the first SOT layer; a second positive voltage lead connected to the second SOT layer and disposed adjacent to the first negative voltage lead; a second negative voltage lead connected to the second SOT layer and disposed adjacent to the first positive voltage lead; The magnetic recording head of claim 14.

19. the read head further comprises a non-magnetic notch disposed between the shield notch and the non-magnetic layer. The magnetic recording head of claim 14.

20. the spin generator is disposed between the first shield and the second shield. The magnetic recording head of claim 14.

21. A magnetic recording head comprising: Magnetic recording device.

22. A read head is provided, The read head comprises: A first shield; A second shield; and a nonmagnetic layer disposed between the first shield and the second shield; a sensor including a first free layer and a second free layer disposed between the first shield and the second shield at a media facing surface (MFS); a spin generator disposed back from the MFS and spaced from the sensor; the spin generator includes a first spin orbit torque (SOT) layer disposed between the first shield and the nonmagnetic layer, and a second SOT layer disposed between the nonmagnetic layer and the second shield. Magnetic recording device.

23. The read head comprises: a first negative current lead connected to the first SOT layer; a first positive current lead connected to the first SOT layer; a second positive current lead connected to the second SOT layer and disposed adjacent to the first negative current lead; a second negative current lead connected to the second SOT layer and disposed adjacent to the first positive current lead; 23. The magnetic recording device according to claim 22.

24. The read head comprises: a first negative voltage lead connected to the first SOT layer; a first positive voltage lead connected to the first SOT layer; a second positive voltage lead connected to the second SOT layer and disposed adjacent to the first negative voltage lead; a second negative voltage lead connected to the second SOT layer and disposed adjacent to the first positive voltage lead; 23. The magnetic recording device according to claim 22.

25. the first free layer is disposed between the first shield and the nonmagnetic layer; the second free layer is disposed between the nonmagnetic layer and the second shield.

23. The magnetic recording device according to claim 22.

26. The read head comprises: a first soft bias side shield disposed adjacent to the first free layer in the MFS; a second soft bias side shield disposed adjacent to the first free layer in the MFS; a third soft bias side shield disposed adjacent to the second free layer in the MFS; a fourth soft bias side shield disposed adjacent to the second free layer in the MFS; a first Ru layer disposed between the first soft bias side shield and the third soft bias side shield; a second Ru layer disposed between the second soft bias side shield and the fourth soft bias side shield; 23. The magnetic recording device according to claim 22.

27. the first free layer is separated from the first SOT layer by a first insulating layer; the second free layer is separated from the second SOT layer by a second insulating layer; 23. The magnetic recording device according to claim 22.

28. the first SOT layer and the second SOT layer each individually have a thickness of 5 nm to 20 nm, a height of 100 nm to 1 μm, and a width of less than 100 nm; 23. The magnetic recording device according to claim 22.

29. the non-magnetic layer extends between the sensor and the spin generator, has a height between 100 nm and 300 nm, and includes a first portion and a second portion; the first portion has a width greater than the second portion and is disposed adjacent to the spin generator; The second portion is disposed adjacent to the sensor.

23. The magnetic recording device according to claim 22.

30. the spin generator is disposed between the first shield and the second shield.

23. The magnetic recording device according to claim 22.

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