MAMR Recording Head with a High-Damping Tail Shield Seed Layer

Abstract

This application is titled "MAMR Recording Head with a High-Damping Tail Shield Seed Layer". A microwave-assisted magnetic recording (MAMR) write head includes a main pole and a tail shield. A spin-transfer torque oscillator device is disposed between the main pole and the tail shield. The spin-transfer torque oscillator device includes a free layer. A tail shield thermal seed layer is disposed between the spin-transfer torque oscillator device and the tail shield. The tail shield thermal seed layer includes a magnetic material doped with a rare-earth element. In certain embodiments, the tail shield thermal seed layer includes a rare-earth element in an atomic percentage of from about 2% to about 10 atomic percent. In certain embodiments, the tail shield thermal seed layer has an inherent damping of from about 0.02 to about 0.2.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202080006792.7 (PCT / US2020 / 023425), titled "MAMR Recording Head with a High-Damping Tail-Shield Seed Layer", filed on March 18, 2020.

[0002] Cross-Reference to Related Applications

[0003] This patent application claims the priority of U.S. Patent Application No. 16 / 730,713, filed on December 30, 2019, which is assigned to the assignee hereof and is incorporated herein by reference in its entirety. Background Art Technical Field

[0005] Embodiments of the present disclosure generally relate to microwave-assisted magnetic recording (MAMR) write heads having a spin-transfer oscillator (STO) device and a high-damping tail-shield seed layer.

[0006] Description of the related art

[0007] At the core of a computer's functionality and capabilities is the storage and writing of data to a data storage device such as a hard disk drive (HDD). The amount of data processed by computers is increasing rapidly. Higher recording densities of magnetic recording media are needed to enhance the functionality and capabilities of computers.

[0008] To achieve higher recording densities of magnetic recording media (such as a recording density exceeding 1 terabit per inch 2 ), the width and pitch of the write tracks are made narrower, and thus the corresponding magnetic recording bits encoded in each write track are made narrower. One challenge in making the width and pitch of the write tracks narrower is to reduce the surface area of the main pole of the magnetic write head at the medium-facing surface. As the main pole becomes smaller and smaller, the write field also becomes smaller and smaller, thus limiting the effectiveness of the magnetic write head.

[0009] Thermal-assisted magnetic recording (HAMR) and microwave-assisted magnetic recording (MAMR) are two energy-assisted recording techniques for improving the recording density of magnetic recording media such as HDDs. In MAMR, a spin-transfer oscillator (STO) device is located next to or near the write element to generate a high-frequency AC field such as in the microwave band. The high-frequency AC field reduces the effective coercivity of the magnetic recording media for storing data and allows for the writing of the magnetic recording media at a lower magnetic write field emitted from the write pole. Therefore, higher recording densities of magnetic recording media can be achieved through MAMR technology. However, a hard disk drive system having an MAMR write head may have an undesirably high level of bit flips in the magnetic medium. Therefore, there is a need in the art for improved MAMR write heads. Summary of the Invention

[0010] In certain embodiments, a microwave-assisted magnetic recording (MAMR) write head includes a main pole and a trailing shield. A spin-transfer torque oscillator device is disposed between the main pole and the trailing shield. The spin-transfer torque oscillator device includes a free layer. A trailing shield thermal seed layer is disposed between the spin-transfer torque oscillator device and the trailing shield. The trailing shield thermal seed layer includes a magnetic material doped with a rare earth element.

[0011] In certain embodiments, a microwave-assisted magnetic recording (MAMR) write head includes a main pole and a trailing shield. A spin-transfer torque oscillator device is disposed between the main pole and the trailing shield. The spin-transfer torque oscillator device includes a free layer. A trailing shield thermal seed layer is disposed between the spin-transfer torque oscillator device and the trailing shield. The trailing shield thermal seed layer includes a magnetic material doped with a rare earth element. The trailing shield thermal seed layer includes rare earth elements in an atomic percentage of about 2% to about 10 atomic percent.

[0012] In certain embodiments, a microwave-assisted magnetic recording (MAMR) write head includes a main pole and a trailing shield. A spin-transfer torque oscillator device is disposed between the main pole and the trailing shield. The spin-transfer torque oscillator device includes a free layer. A trailing shield thermal seed layer is disposed between the spin-transfer torque oscillator device and the trailing shield. The trailing shield thermal seed layer includes a magnetic material doped with a rare earth element. In certain embodiments, the trailing shield thermal seed layer has an intrinsic damping of about 0.02 to about 0.2. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Accordingly, a more particular description of the above-described features of the present disclosure, a more specific description of the present disclosure, and the above brief summary can be obtained by reference to the embodiments, some of which are illustrated in the drawings. It should be noted, however, that the drawings only illustrate typical embodiments of the present disclosure and should not be considered as limiting its scope, as the present disclosure may admit other equally effective embodiments.

[0014] Figure 1 is a schematic diagram of certain embodiments of a magnetic media drive including a write head.

[0015] Figure 2 is a schematic diagram of certain embodiments of a cross-sectional side view of a disk-facing magnetic head assembly.

[0016] Figure 3 is Figure 2 a schematic diagram of certain embodiments of a plan view of the media-facing surface of a MAMR head, wherein a spin-transfer torque oscillator (STO) device is disposed between a main pole and a trailing shield in a track direction.

[0017] Figures 4A to 4DSide cross-sectional views of various embodiments of a STO device of a MAMR write head configured to oscillate due to spin transfer torque.

[0018] Figure 5 is Figures 4A to 4D Schematic diagram of a MAMR write head 210.

[0019] Figure 6 Graph of the AC field amplitude for a STO device with a TS thermal seed layer that does not have high damping.

[0020] Figure 7 Graph of the AC field amplitude for a STO device with a TS thermal seed layer that has high damping.

[0021] For the sake of understanding, wherever possible, the same reference numerals are used to denote the same elements common to the drawings. It is contemplated that elements disclosed in one embodiment can be advantageously used in other embodiments without specific recitation. Detailed Description

[0022] Hereinafter, reference is made to embodiments of the present disclosure. However, it should be understood that the present disclosure is not limited to the specifically described embodiments. Instead, any combination of the following features and elements (whether or not associated with different embodiments) is contemplated to implement and practice the present disclosure. Additionally, although embodiments of the present disclosure may achieve advantages over other possible solutions and / or over the prior art, whether a particular advantage is achieved by a given embodiment is not a limitation of the present disclosure. Thus, the following aspects, features, embodiments, and advantages are illustrative only and are not to be considered elements or limitations of the appended claims unless expressly recited in the claims. Similarly, references to "the present disclosure" should not be construed as a generalization of any inventive subject matter disclosed herein and should not be considered an element or limitation of the appended claims unless expressly recited in the claims.

[0023] As used herein, the terms "above", "below", "between", "on", and other similar terms refer to the relative position of one layer with respect to other layers. Thus, for example, a layer disposed above or below another layer may be in direct contact with the other layer or may have one or more intermediate layers. Additionally, a layer disposed between layers may be in direct contact with both layers or may have one or more intermediate layers. In contrast, a first layer "on a second layer" is in contact with the second layer. The relative positions of these terms do not limit or confine these layers to a particular vector space orientation of these layers.

[0024] The term "comprising / including" includes the subset meaning of "consisting of / consisting essentially of", and includes the subset meaning of "consisting of / formed of".

[0025] Certain embodiments include a spin torque oscillator (STO) device for a microwave-assisted magnetic recording (MAMR) write head, the MAMR write head being disposed in a trailing shield gap between a main pole and a trailing shield (TS). The TS includes a high-damping TS thermal seed layer. The free layer of the STO device of the MAMR head oscillates during writing to provide an assist AC field. However, the free layer can also cause oscillations in the magnetization direction together with other components of the MAMR write head. These oscillations can generate an additional AC field, which can result in increased bit flips at the magnetic medium in the region near the MAMR recording spot and / or reduced assist AC field at the MAMR recording spot. Compared with a low-damping TS thermal seed layer, the lower magnetic moment (Ms) and high damping in the TS thermal seed layer reduce the AC field near the TS thermal seed layer and reduce bit flips.

[0026] Figure 1 FIG. is a schematic diagram of certain embodiments of a magnetic medium drive including a magnetic write head (such as a MAMR head). Such a magnetic medium drive can be a single drive / device or include multiple drives / devices. For purposes of illustration, a single disk drive 100 is shown according to one embodiment. The disk drive 100 includes at least one rotatable disk 112, the at least one rotatable disk being supported on a spindle 114 and rotated by a drive motor 118. The magnetic recording on each disk 112 is in the form of any suitable pattern of data tracks, such as an annular pattern of concentric data tracks (not shown) on the disk 112.

[0027] At least one slider 113 is positioned near the disk 112. Each slider 113 supports a head assembly 121, the head assembly including one or more read / write heads, such as a MAMR head having an STO device. As the disk 112 rotates, the slider 113 moves radially in and out over the disk surface 122 such that the head assembly 121 can access different tracks of the disk 112 for writing desired data. Each slider 113 is attached to an actuator arm 119 by 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. As Figure 1 shown, the actuator 127 can be a voice coil motor (VCM). The VCM includes a coil that can move within a fixed magnetic field, and the direction and speed of the coil movement are controlled by a motor current signal supplied by a control unit 129.

[0028] During operation of the disk drive 100, rotation of the disk 112 generates an air or air bearing between the slider 113 and the disk surface 122, and the air or air bearing exerts an upward force or lift on the slider 113. Thus, during normal operation, the air or air bearing counteracts the slight spring force of the suspension 115 and holds the slider 113 off and slightly above the disk surface 122 by a relatively small substantially constant spacing.

[0029] The various components of the disk drive 100 are controlled in operation by control signals (such as access control signals and internal clock signals) generated by the control unit 129. Generally, the control unit 129 includes a logic control circuit, a storage device, and a microprocessor. The control unit 129 generates control signals that control various system operations, such as a drive motor control signal on line 123 and a head position and seek control signal on line 128. The control signal on line 128 provides a desired current distribution to optimally move and position the slider 113 to a desired data track on the disk 112. Write signals and read signals are transmitted to and from the head assembly 121 through the recording channel 125. Figure 1 Certain embodiments of the magnetic media drive may also include multiple media or disks, multiple actuators, and / or multiple sliders.

[0030] Figure 2 is a schematic diagram of certain embodiments of a cross-sectional side view of a head assembly 200 that is oriented towards the disk 112 or other magnetic storage medium. The head assembly 200 may correspond to Figure 1 the head assembly 121 described in Figure 2 As shown, the disk 112 moves relatively in the direction indicated by arrow 232, and the head assembly 200 moves relatively in the direction indicated by arrow 233.

[0031] In some embodiments, the head assembly 200 includes a magnetic read head 211. The magnetic read head 211 may include a sensing element 204 disposed between shields S1 and S2. In certain embodiments, the sensing element 204 is a magnetoresistive (MR) sensing element, such as an element that utilizes the tunneling magnetoresistance (TMR) effect, the giant magnetoresistance (GMR) effect, the extraordinary magnetoresistance (EMR) effect, or the spin torque oscillator (STO) effect. The magnetic field of a magnetized region in the disk 112 (such as a vertically recorded bit or a longitudinally recorded bit) can be detected as a recorded bit by the sensing element 204.

[0032] The head assembly 200 includes a MAMR write head 210. In certain embodiments, the MAMR write head 210 includes a main pole 220, a front shield 206, a TS 240, and a spin-transfer torque oscillator (STO) device 230 disposed between the main pole 220 and the TS 240. The main pole 220 serves as a first electrode and has a front portion at the MBS.

[0033] The main pole 220 includes a magnetic material such as CoFe, CoFeNi, or FeNi, or other suitable magnetic materials. In certain embodiments, the main pole 220 includes small grains of a magnetic material having a random texture, such as a body-centered cubic (BCC) material formed with a random texture. For example, the random texture of the main pole 220 can be formed by electrodeposition. The MAMR write head 210 includes a coil 218 surrounding the main pole 220 that energizes the main pole 220 to generate a write magnetic field structure for influencing the magnetic medium of the rotatable disk 112. The coil 218 can be a spiral structure or one or more sets of planar structures.

[0034] In certain embodiments, the main pole 220 includes a tail cone 242 and a front cone 244. The tail cone 242 extends from a position recessed in the MFS212 to the MFS 212. The front cone 244 extends from a position recessed in the MFS 212 to the MFS 212. The tail cone 242 and the front cone 244 can have the same or different tapers relative to the longitudinal axis 260 of the main pole 220. In some embodiments, the main pole 220 does not include a tail cone 242 and a front cone 244. Instead, the main pole 220 includes a tail side (not shown) and a front side (not shown), where the tail side and the front side are substantially parallel.

[0035] The TS 240 is a magnetic material such as FeNi or other suitable magnetic materials that serves as a second electrode and a return pole for the main pole 220. The front shield 206 can provide electromagnetic shielding and separates a front gap 254 from the main pole 220.

[0036] The STO device 230 is positioned close to the main pole 220 and reduces the coercivity of the magnetic medium such that a smaller write field can be used to record data. An electronic current is applied from a power supply 270 to the STO device 230 to generate a microwave field. The electronic current can be a direct current (DC) waveform, a pulsed DC waveform, a pulsed current waveform that alternates between a positive voltage and a negative voltage, or other suitable waveforms.

[0037] In some embodiments, the STO device 230 may be electrically coupled to the main pole 220 and the TS 240, where the main pole 220 and the TS are separated by an insulating layer 272. The power supply 270 may provide an electron current to the STO device 230 through the main pole 220 and the TS 240. For a direct current or pulsed current, the power supply 270 may cause the electron current to flow from the main pole 220 through the STO device 230 to the TS 240, or may cause the electron current to flow from the TS 240 through the STO device 230 to the main pole 220, depending on the orientation of the STO device 230. In other embodiments, the STO device 230 may be coupled to electrical leads that provide an electron current that does not originate from the main pole and / or the TS.

[0038] Figure 3 Yes Figure 2 Schematic diagram of certain embodiments of a plan view of the medium-facing surface of the MAMR write head 210, where the STO device 230 is between the main pole 220 and the TS 240 in the track direction. The main pole 220 of the write head 210 can be of any suitable shape (i.e., trapezoidal, triangular, etc.) and suitable size. The STO device 230 can be formed in any suitable shape, any suitable size, and at any suitable position between the main pole 220 and the TS 240. For example, the width 230W of the STO device 230 can be greater than, equal to, or less than the width 220W of the main pole 220 at the interface with the STO device 230.

[0039] The front shield 206 can be positioned on one or more sides of the main pole 220 with a front gap 254 therebetween. The side gap 246 can be positioned on the sides of the STO device 230. The side gap 246 can include an insulating material.

[0040] The track direction is labeled as the x coordinate, and the cross-track direction is labeled as the x coordinate. The vertical direction of the medium-facing surface will be the z coordinate entering / leaving the X-Y plane.

[0041] Figures 4A to 4D Is a side cross-sectional view of various embodiments of the STO device 230 of the MAMR write head 210, which is configured to oscillate due to spin transfer torque. The MAMR write head 210 can be Figure 2 of the MAMR write head or other suitable MAMR write head. The STO device 230 is positioned close to the main pole 220 and reduces the coercivity of the disk 112 or other magnetic storage medium magnetic medium, such that a smaller write field (H Writing Field ) can be used to record data. From Figure 2 the power supply 270 to the STO device 230 applies a bias current (I STO ) that generates an auxiliary AC field (H Assisting Field), such as a microwave field. The auxiliary AC field is formed by the oscillation of the magnetization of the field generation layer (FGL) of the STO device 230 or the free layer 450. The chirality or the direction of rotation of the free layer 450 switches in response to the switching in the write field direction of the main pole 220.

[0042] In some embodiments, as Figure 4A shown, the STO device 230 includes a seed layer 420 above or over the main pole 220, a free layer 450 above or over the seed layer 420, a spacer layer 440 above or over the free layer 450, a high-damping TS thermal seed layer 235 above or over the spacer layer 440, and a TS 240 above or over the high-damping TS thermal seed layer 235. The electron current from the main pole 220 through the STO device 230 to the TS 240 causes polarized electrons to be reflected back from the TS 240 to the free layer 450. The reflected polarized electrons generate a spin-transfer torque on the magnetization of the free layer 450 and cause the magnetization oscillation of the free layer 450.

[0043] In some embodiments, as Figure 4B shown, the STO device 230 includes a spacer layer 440 above or over the main pole 220, a free layer 450 above or over the spacer layer 440, a capping layer 470 above or over the free layer 450, a high-damping TS thermal seed layer 235 above or over the capping layer 470, and a TS 240 above the TS thermal seed layer 235. The electron current from the TS 240 through the STO device 230 to the main pole 220 causes polarized electrons to be reflected back from the main pole 220 to the free layer 450. The reflected polarized electrons generate a spin-transfer torque on the magnetization of the free layer 450 and cause the magnetization oscillation of the free layer 450.

[0044] In some embodiments, as Figure 4C shown, the STO device 230 includes a seed layer 420 above or over the main pole 220, a spin-polarized layer (SPL) 430 above or over the seed layer 420, a spacer layer 440 above or over the SPL 430, a free layer 450 above or over the spacer layer 440, a capping layer 470 above or over the free layer 450, a high-damping TS thermal seed layer 235 above or over the capping layer 470, and a TS 240 above or over the high-damping TS thermal seed layer 235. The electron current from the main pole 220 through the STO device 230 to the TS 240 imparts spin polarization to the electrons from the SPL 430. The polarized electrons from the SPL 430 generate a spin-transfer torque on the magnetization of the free layer 450 and cause the magnetization oscillation of the free layer 450. The TS 240 can reflect the polarized electrons towards the free layer 450 to increase the spin-transfer torque on the free layer 450.

[0045] In some embodiments, such as Figure 4D shown, the STO device 230 includes a first spacer layer 440A above or over the main pole 220, a free layer 450 above or over the first spacer layer 440A, a second spacer layer 440B above or over the free layer 450, a spin-polarized layer (SPL) 430 above or over the second spacer layer 440B, a capping layer 470 above or over the SPL 430, a high-damping TS thermal seed layer 235 above or over the capping layer 470, and a TS 240 above or over the high-damping TS thermal seed layer 235. An electron current from the TS 240 through the STO device 230 to the main pole 220 imparts spin polarization to electrons from the SPL 430. The polarized electrons from the SPL 430 generate a spin-transfer torque on the magnetization of the free layer 450 and cause magnetization oscillation of the free layer 450. The main pole 220 may reflect the polarized electrons toward the free layer 450 to increase the spin-transfer torque on the free layer 450.

[0046] In some embodiments, Figures 4A to 4D the free layer 450 of the STO device 230 of includes one or more magnetic alloy layers that include Fe, Co, FeCo, NiFe, CoFeAl, CoFeGe, CoMnGe, CoFeSi, CoMnSi, and other magnetic materials. For example, in some embodiments, the free layer 450 includes ferromagnetic materials having a high magnetic moment and high spin polarization, such as FeCo and FeCo alloys.

[0047] In some embodiments, Figures 4A to 4D the spacer layer 440 of the STO device 230 of includes one or more non-magnetic conductive materials, such as Au, Ag, Cu, AgSn, NiAl, other non-magnetic conductive materials, their alloys, or multiple layers thereof. The spacer layer 440 may be made of a material having high spin transmissivity for spin torque transfer on the free layer 450.

[0048] In some embodiments, Figure 4B the SPL 430 of the STO device 230 of or 4D includes NiFe, CoFe, CoFeNi, CoMnGe, NiCo, NiFeCu, CoFeMnGe, CoMnSi, CoFeSi, other soft or hard ferromagnetic materials, other Heusler alloys, other suitable magnetic layers, or multiple layers thereof. The SPL 430 may include a material having magnetic anisotropy that is oriented along any generally direction (such as perpendicular, angled, or longitudinal) with respect to the plane of the disk 112 or other magnetic recording medium.

[0049] In some embodiments, Figure 4AThe seed layer 420 of the STO device 230 of 4C or 4D comprises ruthenium, copper, tantalum, other non-magnetic materials, alloys thereof, or multiple layers thereof. In certain embodiments, the seed layer 420 resets or provides texture fissures for the growth of the SPL 430, which has low structural defects on the seed layer 420. The low structural defects of the SPL 430 result in greater magnetic uniformity of the SPL 430, reduce the critical current required for the SPL 430 to reverse, and increase the yield of the formation of the SPL 430. For example, a seed layer comprising tantalum over copper provides a nanocrystalline structure formed over the random texture of the main pole 220. The nanocrystalline structure provides a smooth surface for the formation of a structured layer or a crystalline layer having low structural / crystalline defects thereover. In certain embodiments, the seed layer 420 provides a surface to facilitate the good growth of a structured layer and / or a crystalline layer such as a face-centered cubic (FCC) metal alloy, a body-centered cubic (BCC) metal alloy, and an ordered phase alloy. For example, the seed layer 420 comprising ruthenium has a hexagonal close-packed structure. The hexagonal close-packed (HCP) structure provides a good template surface to facilitate the growth of or interface contact with an FCC layer, a BCC layer, or a Heusler layer having low structural defects. In certain embodiments, the seed layer 420 removes electron spin polarization from the main pole 220.

[0050] In certain embodiments, Figure 4B The capping layer 470 of the STO device 230 of 4D or 4D comprises one or more layers of a non-magnetic conductive material, a metal or a metal alloy of Ru, Ir, Ta, Ti, and other non-magnetic metals. During the formation of the STO device and the formation of the MAMR write head 210, such as during deposition, annealing, patterning, cleaning, etc., the capping layer 470 can protect the STO device 230.

[0051] In certain embodiments, a notch structure can be formed above the TS thermal seed layer 235, or the TS thermal seed layer 235 and the TS 240 can form a pedestal structure (collectively referred to as the notch tail shield). The notch tail shield can reflect polarized electrons towards the free layer 450 to increase the spin transfer torque on the free layer 450, such as in Figure 4A and Figure 4C the STO device of.

[0052] Figures 4A to 4D The high-damping TS thermal seed layer 235 of the STO device 230 of Figures 4A to 4D comprises a magnetic material doped with one or more rare-earth metals. Examples of the magnetic material include CoFe and CoFe alloys. The rare-earth metals include holmium (Ho), dysprosium (Dy), terbium (Tb), samarium (Sm), other rare-earth metals, or combinations thereof. A specific example of the high-damping TS thermal seed layer 235 is CoFeHo.

[0053] The damping in the TS thermal seed layer is affected by the combination of certain magnetic materials and certain doping materials. In certain embodiments, the TS thermal seed layer 235 includes an atomic percentage content of rare earth metals in the range of about 2% to about 10%. A high-damping TS thermal seed layer 235 with a rare earth metal content greater than 10% may be undesirable because this rare earth metal content extremely reduces the magnetic moment (Bs) of the TS thermal seed layer, thereby reducing the write field gradient, and / or makes the TS thermal seed layer prone to corrosion during manufacturing and / or during operation. A high-damping TS thermal seed layer 235 with a rare earth metal content less than 2% may be undesirable because a certain amount of damping may not be achievable to reduce the oscillation of the TS thermal seed layer caused by the oscillation of the free layer 450.

[0054] In certain embodiments, the TS thermal seed layer 235 has an inherent damping of about 0.02 to about 0.2. The inherent damping in a magnetic system (thin film, multilayer stack, or structural device) is a physical property of the magnetic system. The damping in the TS thermal seed layer of a MAMR write head is determined by separating the TS thermal seed layer or forming a similar sample of the TS thermal seed layer and measuring the inherent damping in the separated TS thermal seed layer or the similar sample of the TS thermal seed layer using ferromagnetic resonance (FMR) measurements at 20 °C with a PhaseFMR tool available from NanOsc Instruments AB, Kista, Sweden. The inherent damping, also known as Gilbert damping, is a dimensionless parameter determined by the Landau-Lifschitz-Gilbert equation. An inherent damping greater than 0.2 may be undesirable because the magnetic moment (B) of the TS thermal seed layer may be too low and may reduce the write field gradient. An inherent damping less than 0.02 may be undesirable because a certain amount of damping may not be achievable to reduce the oscillation of the TS thermal seed layer caused by the oscillation of the free layer 450.

[0055] Figure 5 is a MAMR write head such as Figures 4A to 4DSchematic diagram of the MAMR write head 210). The main pole 220 is energized through the write coil 218 in the magnetization direction 220A, which causes the TS thermal seed layer 235 to be in the magnetization direction 235A. The current applied to the STO device 230 causes the magnetization direction 450A of the free layer 450 to oscillate. The oscillation of the free layer 450 causes the oscillation of the TS thermal seed layer 235. The oscillation of the thermal seed layer generates an additional AC field near the thermal seed layer. When the TS thermal seed layer includes a low-damping material, the additional AC field near the TS thermal seed layer may be relatively large, such as greater than 400 Oe in a direction perpendicular to the surface facing the medium, which may inadvertently cause bit flips in the magnetic medium, such as inadvertently writing to the magnetic medium or inadvertently erasing the magnetic medium. When the TS thermal seed layer 235 includes a high-damping material, the additional AC field near the TS thermal seed layer is reduced in the vertical direction, such as reduced to 400 Oe or less, reduced to about 200 Oe or less. This reduces bit flips in the magnetic medium, such as reducing inadvertent writing to and / or inadvertent erasing of the magnetic medium.

[0056] By minimizing the amplitude of the oscillation of the TS thermal seed layer, the contribution of the AC field from the thermal seed layer can be reduced. Doping the TS thermal seed layer with rare earth metals reduces the magnetic moment (M s ) of the TS thermal seed layer and reduces the amplitude of the oscillation of the TS thermal seed layer by providing high damping in the TS thermal seed layer.

[0057] In some embodiments, a microwave-assisted magnetic recording (MAMR) write head includes a main pole and a trailing shield. A spin torque oscillator device is disposed between the main pole and the trailing shield. The spin torque oscillator device includes a free layer. A trailing shield thermal seed layer is disposed between the spin torque oscillator device and the trailing shield. The trailing shield thermal seed layer includes a magnetic material doped with a rare earth element. In some embodiments, the trailing shield thermal seed layer includes a rare earth element in an atomic percentage of about 2% to about 10% atomic percentage. In some embodiments, the trailing shield thermal seed layer has an intrinsic damping of about 0.02 to about 0.2.

[0058] Embodiment

[0059] Figure 6 is a graph of the amplitude of the AC field of an STO device having a TS thermal seed layer without high damping along the down-track position from the main pole region (-40) to the TS thermal seed region (+40). The amplitude of the AC field is measured by the magnetic field intensity in the down magnetic field (hd), the cross magnetic field (hc), and the perpendicular field (hp) of the surface facing the medium. The measurement is performed at a frequency of 20 GHz. The TS thermal seed without high damping includes an intrinsic damping (α int) The CoFe. STO device has an AC field with a vertical component of approximately 500 Oe in the TS thermal seeding region.

[0060] Figure 7 It is an amplitude curve graph of the AC field of an STO device having a TS thermal seeding layer with high damping along the down-track position from the main pole region (-40) to the TS thermal seeding region (+40). The amplitude of the AC field is measured by the magnetic field strength in the downward magnetic field (hd), the cross magnetic field (hc), and the vertical field (hp) facing the surface of the medium. The measurement is carried out at a frequency of 20 GHz. The TS thermal seeding with high damping includes CoFeHo having an intrinsic damping of 0.10 (α int ) The CoFeHo. STO device has an AC field with a vertical component of approximately 375 Oe in the TS thermal seeding region.

[0061] While the foregoing is directed to embodiments of the present disclosure, other and additional embodiments of the present disclosure may be envisioned without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the appended claims.

Claims

1. A microwave-assisted magnetic recording write head, i.e., a MAMR write head, comprising: A main pole and a trailing shield; A spin torque oscillator device disposed between the main pole and the trailing shield, the spin torque oscillator device including a free layer; and A high-damping trailing shield thermal seed layer disposed between the spin torque oscillator device and the trailing shield, the high-damping trailing shield thermal seed layer having an intrinsic damping of from about 0.02 to about 0.

2.

2. The MAMR write head according to claim 1, wherein the high-damping trailing shield thermal seed layer is configured to generate an AC field of about 400 Oe or less in a direction perpendicular to the medium-facing surface of the high-damping trailing shield thermal seed layer.

3. The MAMR write head according to claim 1, wherein the high-damping trailing shield thermal seed layer is configured to generate an AC field of about 200 Oe or less in a direction perpendicular to the medium-facing surface of the high-damping trailing shield thermal seed layer.

4. The MAMR write head according to claim 1, wherein the spin torque oscillator device is configured to oscillate the magnetization direction of the free layer due to spin transfer torque from polarized electrons directed at the free layer.

5. The MAMR write head according to claim 1, wherein the spin torque oscillator device further includes a spin-polarized layer configured to direct polarized electrons toward the free layer to oscillate the magnetization direction of the free layer due to spin transfer torque.

6. A magnetic medium drive comprising the MAMR write head according to claim 1.

7. A magnetic write head, comprising: A main pole and a trailing shield; And A high-damping trailing shield thermal seed layer disposed between the main pole and the trailing shield, the high-damping trailing shield thermal seed layer having an intrinsic damping of from about 0.02 to about 0.

2.

8. The magnetic write head according to claim 7, wherein the high-damping trailing shield thermal seed layer is configured to generate an AC field of about 400 Oe or less in a direction perpendicular to the medium-facing surface of the high-damping trailing shield thermal seed layer.

9. The magnetic write head according to claim 7, wherein the high-damping trailing shield thermal seed layer is configured to generate an AC field of about 200 Oe or less in a direction perpendicular to the medium-facing surface of the high-damping trailing shield thermal seed layer.

10. The magnetic write head according to claim 7, further comprising a free layer disposed between the main pole and the trailing shield, wherein the magnetization direction of the free layer is configured to oscillate due to spin transfer torque from polarized electrons directed at the free layer.

11. The magnetic write head according to claim 10, further comprising a spin-polarized layer configured to direct polarized electrons toward the free layer to oscillate the magnetization direction of the free layer due to spin transfer torque.

12. A magnetic medium drive comprising the magnetic write head according to claim 7.

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