Headway Technologies, Incorporated

Hitachi Global Storage Technologies Netherlands B.v.

Wenyu Chen

Yan Wu

Shohei Kawasaki

Yuhui Tang

Min Li

Kunliang Zhang

Ying Liu

Tetsuya Roppongi

Joe Smyth

Glen A Garfunkel

Ruhang Ding

Yewhee Chye

Yue Liu

Kowang Liu

Shehrin Sayed

Haowen Ren

Yoshitaka Sasaki

Hiroyuki Ito

Yuchen Zhou

Shigeki Tanemura

Hironori Araki

Kazuki Sato

Moris Musa Dovek

Bruce David Terris

Liesl Folks

Junjie Quan

Yoji Nomura

Tetsuhito Shinohara

Wenjie Chen

Sylvia Helena Florez Marino

Alain Truong

Zhenyao Tang

The present embodiments relate to a magnetic write head structure that improves the maximum allowable bias current to maximize the current-assisted areal density capacity (ADC) gain in hard-disk-drive storage device. The write head can include a magnetic main pole (MP) and a trailing shield (TS) made of magnetic material that collects back the magnetic flux and a write gap (WG) between the MP and the TS that is comprised of a non-magnetic electrical conductor. The WG can include a height that is greater than an eTHd height of the HS that can increase an electrical contact area between the HS and MP for a bias current flow. The WG can further include a first part extending an air-bearing surface (ABS) plane of the write head to a top of the eTHd height and a second part extending from the top of the eTHd height.

Recessed write gap material for enhanced bias current injection and maximizing aerial density capacity in perpendicular magnetic recording

The present embodiments relate to write heads implementing microwave-assisted magnetic recording utilizing multiple spin torque oscillators (STOs). Each STO can include a field-generation layer (FGL) that can oscillate in a same frequency and out of phase with one another. The layers in each STO can enable mutual spin transfer torques between adjacent layers, which can drive the FGLs into a large angle oscillation. The oscillation between the FGLs can cause a magnetic field to be generated that can assist in writing to a magnetic recording medium.

Dual-spin torque oscillator designs in microwave assisted magnetic recording

A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or in another embodiment, the PM layer adjoins a backside of the top shield and has a width equal to or greater than that of the FL.

Adaptive bias control for magnetic recording head

A read head is disclosed wherein a Spin Hall Effect (SHE) layer is formed on a free layer (FL) in a sensor and between the FL and top shield (S). Preferably, the sensor has a seed layer, an APreference layer, antiferromagnetic coupling layer, APreference layer, and a tunnel barrier sequentially formed on a bottom shield (S). When the stripe heights of the FL and SHE layer are equal, a two terminal configuration is employed where a current flows between one side of the SHE layer to a center portion thereof and then to S, or vice versa. As a result, a second spin torque is generated by the SHE layer on the FL that opposes a first spin torque from the APreference layer on the FL.

Reader noise reduction using spin hall effects

The present embodiments can generally provide a magnetic write head structure with optimized gap current distribution to maximize the current-assisted areal density capacity (ADC) gain in hard-disk-drive storage devices. In a first example embodiment, a non-dual-write-shield (nDWS) write head can include a main pole (MP), a trailing shield (TS), and a write gap (WG) disposed between the MP and the TS. The write head can also include a side shield (SS), a leading shield (LS), and a write shield (WS). The write head can include a side gap (SG) between the MP and the SS on both sides of the MP tip, and a leading gap (LG) between the MP and the LS. The write head can also include a coil wrapped around the MP through a PP3 shield that is configured to direct a time-dependent write current to saturate magnetization of the MP.

Optimizing a current distribution in write heads for efficient energy-assisted magnetic recording

A STRAMR structure is disclosed. The STRAMR structure can include a spin torque oscillator (STO) device in a WG provided between the mail pole (MP) trailing side and a trailing shield. The STO device, includes: a flux guiding layer that has a negative spin polarization (nFGL) with a magnetization pointing substantially parallel to the WG field without the current bias and formed between a first spin polarization preserving layer (ppL1) and a second spin polarization preserving layer (ppL2); a positive spin polarization (pSP) layer that adjoins the TS bottom surface; a non-spin polarization preserving layer (pxL) contacting the MP trailing side; a first negative spin injection layer (nSIL1) between the ppL2 and a third spin polarization preserving layer (ppL3); and a second negative spin injection layer (nSIL2) between the ppL3 and the pxL, wherein the nFGL, nSIL1, and nSIL2 have a spin polarization that is negative.

Magnetic flux guiding device with spin torque oscillator (STO) film having negative spin polarization layers in assisted writing application

A read head is disclosed wherein a Spin Hall Effect (SHE) layer is formed on a free layer (FL) in a sensor and between the FL and top shield (S). Preferably, the sensor has a seed layer, an AP2 reference layer, antiferromagnetic coupling layer, AP1 reference layer, and a tunnel barrier sequentially formed on a bottom shield (S). When the stripe heights of the FL and SHE layer are equal, a two terminal configuration is employed where a current flows between one side of the SHE layer to a center portion thereof and then to S, or vice versa. As a result, a second spin torque is generated by the SHE layer on the FL that opposes a first spin torque from the AP1 reference layer on the FL.

A read head is disclosed wherein a Spin Hall Effect (SHE) layer is formed on a free layer (FL) in a sensor and between the FL and top shield (S2). Preferably, the sensor has a seed layer, an AP2 reference layer, antiferromagnetic coupling layer, AP1 reference layer, and a tunnel barrier sequentially formed on a bottom shield (S1). In a three terminal configuration, a first current flows between S1 and S2 such that the AP1 reference layer produces a first spin torque on the FL, and a second current flows across the SHE layer thereby generating a second spin torque on the FL that opposes the first spin torque. When the stripe heights of the FL and SHE layer are equal, a two terminal configuration is employed where a current flows between one side of the SHE layer to a center portion thereof and then to S1, or vice versa.

A method of forming a spin transfer torque reversal assisted magnetic recording (STRAMR) writer is disclosed wherein a spin torque oscillator (STO) has a flux guiding layer (FGL) wherein magnetization flips to a direction substantially opposing the write gap (WG) field when sufficient current (I) density is applied across the STO between a trailing shield and main pole (MP) thereby enhancing the MP write field. The FGL has a center portion with a larger magnetization saturation&#xd7;thickness (MsT) than in FGL outer portions proximate to STO sidewalls. Accordingly, lower Idensity is necessary to provide a given amount of FGL magnetization flipping and there is reduced write bubble fringing compared with writers having a FGL with uniform MsT. Lower MsT is achieved by partially oxidizing FGL outer portions. In some embodiments, there is a gradient in outer FGL portions where MsT increases with increasing distance from FGL sidewalls.

Writer with laterally graded spin layer MsT

A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or a width equal to the cross-track distance between outer sides of the longitudinal bias layers. In another embodiment, the PM layer adjoins a backside of the top shield.

A spin transfer torque reversal assisted magnetic recording (STRAMR) writer is disclosed wherein a spin torque oscillator has a flux guiding layer (FGL) wherein magnetization flips to a direction substantially opposing the write gap (WG) field when sufficient current (I) density is applied across the STO between a trailing shield and main pole (MP) thereby enhancing the MP write field. A key feature is that the FGL has a center portion with a larger magnetization saturation&#xd7;thickness (MsT) than in FGL outer portions proximate to STO sidewalls. Accordingly, lower Idensity is necessary to provide a given amount of FGL magnetization flipping and there is reduced write bubble fringing compared with writers having a FGL with uniform MsT. Lower MsT is achieved by partially oxidizing FGL outer portions. In some embodiments, there is a gradient in outer FGL portions where MsT increases with increasing distance from FGL sidewalls.

A magnetic head includes a medium facing surface, a main pole, a trailing shield, and a spin torque oscillator. A bottom surface of the trailing shield includes a first portion that includes an end located in the medium facing surface and is in contact with the spin torque oscillator at least in part. An element height that is a dimension of the spin torque oscillator in a direction perpendicular to the medium facing surface and a writer height that is a dimension of the first portion in the direction perpendicular to the medium facing surface are different from each other.

Magnetic head including spin torque oscillator

A read head is disclosed wherein a Spin Hall Effect (SHE) layer is formed on a free layer (FL) in a sensor and between the FL and top shield (S). Preferably, the sensor has a seed layer, an AP2 reference layer, antiferromagnetic coupling layer, AP1 reference layer, and a tunnel barrier sequentially formed on a bottom shield (S). In a three terminal configuration, a first current flows between Sand Ssuch that the AP1 reference layer produces a first spin torque on the FL, and a second current flows across the SHE layer thereby generating a second spin torque on the FL that opposes the first spin torque. When the stripe heights of the FL and SHE layer are equal, a two terminal configuration is employed where a current flows between one side of the SHE layer to a center portion thereof and then to S, or vice versa.

Growing community of inventors

San Jose, CA, United States of America

Wenyu Chen