Headway Technologies, Incorporated

Seagate Technology Incorporated

Maxtor Corporation

Yan Wu

Wenyu Chen

Moris Musa Dovek

Zhigang Bai

Kowang Liu

Min Li

Glen A Garfunkel

Shohei Kawasaki

Kunliang Zhang

Cherng-Chyi Han

Yuhui Tang

Ying Liu

Jiun-Ting Lee

Urmimala Roy

Tetsuya Roppongi

Yue Liu

Michael L Mallary

Kenichi Takano

Min Zheng

Yewhee Chye

Jianing Zhou

Yuchen Zhou

Po-Kang Wang

Bruce Douglas Buch

Joe Smyth

Gang Herbert Lin

Cherng Chyi Han

Jeffrey Vincent DeRosa

Joseph Francis Smyth

David Hu

John VanLaanen

Junjie Quan

Ruhang Ding

Yuzuru Iwai

A spin injection assisted magnetic recording structure is disclosed wherein a ferromagnetic (FM) layer and at least one spin preservation (SP) layer are formed between a main pole (MP) trailing side and a write shield (WS). Current (Ia) flows between the MP and WS, or is injected into the FM layer. As a result, the spin polarized electrons from the FM layer, which flow across one or two SP layers to generate a magnetization that enhances one or both of a local WS magnetization and return field, and a local MP magnetization and write field, respectively. A lead to the FM layer may be stitched to enable lower resistance and improve reliability. The FM layer may be recessed from the ABS to allow more overlap with the SP layer for lower current density while maintaining performance. Higher linear density and area density capability, and better reliability are achieved.

Spin injection assisted magnetic recording

The present embodiments relate to a perpendicular magnetic recording (PMR) write head with a Tunable Pole Protrusion or Tunable Pole Performance (TPP) side bridge design. A PMR write head can include a main pole including a tip portion configured to be disposed at an air-bearing surface (ABS) and configured to interact with a magnetic recording medium. The PMR write head can also include a hot seed (HS) portion and a first write shield. The PMR write head can also include a first metallic side bridge disposed between the tip portion of the main pole and the HS portion. The PMR write head can also include a bias circuit including at least a first bias electrical pad and a second electrical bias pad directing an electrical current flow along an electrical path between the tip portion of the main pole and the write shield portion via the first metallic side bridge.

Perpendicular magnetic recording writer with tunable pole side bridge design

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

A PMR (perpendicular magnetic recording) write head is configured for measurements at the slider level and wafer-level processing stages that will allow a determination of the pole width at a position A (PWA) using the results of a resistance measurement between a main pole (MP) and surrounding write shields (WS) with a layer of conductor in the write gap and a layer of insulating material replacing the side gaps. Knowledge of an accurate value of PWA allows adjustments to be made in the processing of sliders on each rowbar which, in turn improves the capability of delivering the desired statistical variation (sigma) in the distribution of erasure widths for AC signals (EWACS) in a given design which, in turn, gives better overall performance in hard disk drive (HDD) applications.

Built-in resistance sensor for measuring slider level pole width at point 'A' (PWA) for PMR/MAMR writers

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 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 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.

A perpendicular magnetic recording (PMR) writer is disclosed wherein an insulation layer is formed between a top yoke (TY) and an uppermost (PP3) trailing shield to electrically isolate the main pole (MP) from a trailing loop for magnetic flux return. One or both of a first non-magnetic (NM) metal layer and a second NM metal layer are formed between the MP tip and a hot seed layer and side shields, respectively, to form an electrical path that is in parallel to that of a dynamic fly height (DFH) heater circuit. MP tip protrusion is enhanced and writability is improved especially for track widths &#x3c;40 nm, and is tunable by the volume of the first and second NM layer, and the composition of the NM metals. Existing writer pad layouts may be employed and there is no additional cost to PMR backend processes.

Perpendicular magnetic recording (PMR) writer with tunable pole protrusion (TPP) designs for 2 terabytes/platter (TB/P) and beyond

A spin transfer torque reversal assisted magnetic recording (STRAMR) device is disclosed wherein a flux change layer (FCL) is formed between a main pole (MP) trailing side and a trailing shield (TS). The FCL has a magnetization that flips to a direction substantially opposing the write gap magnetic field when a direct current (DC) of sufficient current density is applied across the STRAMR device thereby increasing reluctance in the WG and producing a larger write field output at the air bearing surface. Heat transfer in the STRAMR device is enhanced and production cost is reduced by enlarging the STRAMR width to be essentially equal to that of the TS, and where the TS and STRAMR widths are formed using the same process steps. Bias voltage is used to control the extent of FCL flipping to a center portion to optimize the gain in area density capability in the recording system.

Spin torque reversal assisted magnetic recording (STRAMR) device having a width substantially equal to that of a traililng shield

A spin torque reversal assisted magnetic recording (STRAMR) structure is disclosed wherein a spin torque oscillator (STO) is formed in the write gap (WG) and generates one or both of a radio frequency (RF) field on a magnetic bit to lower the required write field during a write process, and a spin torque on a field generation layer (FGL) in the STO that flips a FGL magnetization to a direction opposing the WG field thereby increasing reluctance in the WG and causing larger write field output from the main pole (MP). The FGL is between two spin preserving layers that each conduct spin polarized current from an adjoining spin polarization (SP) layer. Current is applied from the MP and trailing shield to the SP layers, and returns to a direct current source through a lead from the FGL. STO sidewalls are self-aligned to a MP tip upper portion.

Growing community of inventors

Cupertino, CA, United States of America

Yan Wu