Headway Technologies, Incorporated

International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Glen A Garfunkel

Min Li

Moris Musa Dovek

Kunliang Zhang

Yan Wu

Edward Hinpong Lee

Yewhee Chye

Joseph Francis Smyth

Junjie Quan

Neil Leslie Robertson

Wenyu Chen

Douglas Johnson Werner

Po Kang Wang

Samuel Wonder Yuan

Yuchen Zhou

Edward Hin Pong Lee

Albert John Wallash

Shohei Kawasaki

Devendra S Chhabra

Robert G Biskeborn

David John Seagle

Cherng-Chyi Han

Kenichi Takano

Thomas Young Chang

Rod Lee

Donald E Horne

Sanford J Lewis

Carol Yoshiko Inouye

Robert Owen Barr

Po-Kang Wang

John Thomas Contreras

Cherngye Hwang

Daniele Mauri

Wen-Chien David Hsiao

Yuhui Tang

Yue Liu

Andrew Ching Tam

A David Erpelding

Surya Narayan Pattanaik

Joe Smyth

Yaguang Wei

Kowang Liu

Kenji Kuroki

Akihiko Aoyagi

Chie Ching Poon

Christopher H Bajorek

Michael Paul Salo

Hiroshi Yanagisawa

David Hu

Alain M Desouches

Wen Yaung Lee

Robert Langland Smith

Ruhang Ding

Calvin Shizuo Nomura

Saad K Doss

Yuzuru Iwai

Mor Dovek

Wen-Chien (David) Hsiao

Wen Chien David Hsiao

Wen Chien Hsiao

Hiroshima Terashima

Mike P Salo

John P Herber

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 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 hard magnet stabilization scheme is disclosed for a top shield and junction shields for double or triple dimension magnetic reader structures. In one design, the hard magnet (HM) adjoins a top or bottom surface of all or part of a shield domain such that the HM is recessed from the air bearing surface to satisfy reader-to-reader spacing requirements and stabilizes a closed loop magnetization in the top shield. The HM may have a height and width greater than that of the top shield. The top shield may have a ring shape with a HM formed above, below, or within the ring shape, and wherein the HM stabilizes a vortex magnetization. HM magnetization is set or reset from room temperature to 100&#xb0; C. to maintain a desired magnetization direction in the top shield, junction shield, and free layer in the sensor.

Hard magnetic stabilized shield for double (2DMR) or triple (3DMR) dimension magnetic reader structures

Hard magnet stabilized shield for double (2DMR) or triple (3DMR) dimension magnetic reader structures

A hard magnet stabilization scheme is disclosed for a top shield and junction shields for double or triple dimension magnetic reader structures. In one design, the hard magnet (HM) adjoins a top or bottom surface of all or part of a shield domain such that the HM is recessed from the air bearing surface to satisfy reader-to-reader spacing requirements and stabilizes a closed loop magnetization in the top shield. Alternatively, the HM may replace a shield domain. The top shield may have various shapes including a ring shape in which the HM stabilizes a vortex magnetization. In a whole shield coupling design, the HM contacts all of the top shield bottom surface except over the sensor and junction shield. HM magnetization is set or reset from room temperature to 100&#xb0; C. to maintain a desired magnetization direction in the top shield, junction shield, and free layer in the sensor.

A read head is longitudinally biased unidirectionally by laterally abutting soft magnetic layers or multilayers. The soft magnetic layers are themselves magnetically stabilized by layers of antiferromagnetic material that are exchange coupled to them. The same layers of antiferromagnetic materials can be used to stabilize a unidirectional anisotropy of an overhead shield by means of exchange coupling. By including the antiferromagnetic material layer within the patterned biasing structure itself, an additional layer of antiferromagnetic material that normally covers the entire sensor structure is eliminated. The elimination of an entire layer is also advantageous for reducing the inter-sensor spacing in a TDMR (two dimensional magnetic recording) configuration where two sensor are vertically stacked on top of each other.

Bias layer and shield biasing design

A MR sensor is disclosed with an antiferromagnetic (AFM) layer recessed behind a first stack of layers including a free layer and non-magnetic spacer to reduce reader shield spacing and enable increased areal density. The AFM layer may be formed on a first pinned layer in the first stack that is partially embedded in a second pinned layer having a front portion at an air bearing surface (ABS) to improve pinning strength and avoid a morphology effect. In another embodiment, the AFM layer is embedded in a bottom shield and surrounds the sidewalls and back side of an overlying free layer in the sensor stack to reduce reader shield spacing. Pinning strength is improved because of increased contact between the AFM layer and a pinned layer. The free layer is aligned above a bottom shield center section.

Reader designs of shield to shield spacing improvement

A shield structure for a PMR writer is disclosed and features a first trailing shield on a write gap, and a second (PP) trailing shield on the first trailing shield and magnetically connected to the main pole layer. From a top-down view along the down-track direction, the PPtrailing shield has various shapes to provide shape anisotropy such that following hard magnet or reverse magnet initialization, PPtrailing shield magnetic orientation has a stable three domain configuration thereby minimizing skip track erasure (STE) or improving area density capability (ADC). At least one sloped side is introduced that forms an angle &#x3e;90 degrees with the PPtrailing shield backside. In other embodiments, a thinner leading shield may be used to improve STE. The PPtrailing shield may have a dome shape or a planar shape from a down-track cross-sectional view.

PP3 shape designs for shield domain control to improve either skip track erasure (STE) or write performance for perpendicular magnetic recording (PMR)

A composite side shield structure is disclosed for providing biasing to a free layer in a sensor structure. The sensor is formed between a bottom shield and top shield each having a magnetization in a first direction that is parallel to an ABS. The side shield is stabilized by an antiferromagnetic (AFM) coupling scheme wherein a bottom (first) magnetic layer is AFM coupled to a second magnetic layer which in turn is AFM coupled to an uppermost (third) magnetic layer. First and third magnetic layers each have a magnetization aligned in the first direction and are coupled to bottom and top shields, respectively, for additional stabilization. The top shield may be modified to include an AFM scheme for providing additional stabilization and guidance to magnetic moments within AFM coupled magnetic layers in the top shield, and to the third magnetic layer in the side shield.

Thin seeded antiferromagnetic coupled side shield for sensor biasing applications

A method is described to improve performance of a magneto-resistive (MR) sensor under conditions of high areal density. The free layer is partially etched away, the removed material being replaced by a magnetic flux guide structure that reduces the free layer's demagnetization field. This in turn reduces the stripe height of the sensor so that the resolution and the read-back signal are enhanced without increasing noise and instability.

Method to improve performance of a magneto-resistive (MR) sensor

A read head with two read sensors enables reading of a magnetically recorded medium of increased areal densities such as would be provided by two-dimensional magnetic recording. The two sensors, which may be formed in separate depositions, are arranged vertically relative to each other as top and bottom sensors, with a downtrack displacement between them that is less than 900 A and a crosstrack displacement that is less than 600 A. Their separate free layers are connected by four or three conducting leads and require no junctions for their connections. In one embodiment each sensor has separate top and bottom shields and leads. In another embodiment, there is a common shield and lead between the two sensors, but a separate top shield/lead for the top sensor and bottom shield/lead for the bottom sensor.

Two sensor reader for hard disk drive (HDD)

A read head structure is disclosed with a dual piece heat sink layer having a front piece formed over a front portion of a dynamic flying height (DFH) element and a back piece above a back portion of the DFH element. A first (S1) shield is formed on the front piece and between the front piece and air bearing surface (ABS). Front and back pieces are separated by an insulator gap. The front piece is used to help control read gap protrusion. As a result, a bottom portion of the S1 shield protrudes to a greater extent than a top portion adjacent to the sensor thereby protecting the sensor from unwanted contact with the magnetic media. The dual piece heat sink layer also enables an improved Figure of Merit in terms of temperature rise in the reader per unit of actuation (nm) delivered by the DFH element.

Dual-piece heat sink layer for robust reader in magnetic recording head

As track densities increase, it becomes increasingly important, while writing in a given track, not to inadvertently write data in adjoining tracks. This problem has been overcome by limiting the width of material in the ABS plane to what it is at the write gap. The part of the lower pole that is wider than this is recessed back away from the ABS, thereby greatly reducing its magnetic influence on adjacent tracks. Four different embodiments of write heads that incorporate this notion are described together with a description of a general process for their manufacture.

Write head having recessed magnetic material in gap region

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Palo Alto, CA, United States of America

Glen A Garfunkel