Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Hgst Netherlands, B.v.

Avalanche Technology, Inc.

Tsann Lin

Daniele Mauri

Ching Hwa Tsang

Kim Yang Lee

Hardayal Singh Gill

Robert Fontana

Kuok San Ho

David Eugene Heim

Wen Yaung Lee

Cherngye Hwang

David John Seagle

Edward Hin Pong Lee

James K Howard

Jih-Shiuan Luo

Huey-Ming Tzeng

Wen-yaung Lee

Norbert Staud

Richard Hsiao

Albert John Wallash

Alexander Michael Zeltser

Ying Hong

Chun-Ming Wang

Jinshan Li

Hugo Alberto Santini

Meng Ding

Joseph Francis Smyth

Robert John Wilson

Danielle Mauri

Mustafa Pinarbasi

Zheng Gao

Kochan Ju

James Mac Freitag

Bruce Alvin Gurney

Neil Leslie Robertson

Neil Smith

Liubo Hong

Wipul Jayasekara

Howard Gordon Zolla

Jyh-Shuey Jerry Lo

Satoru Araki

Stuart Stephen Parkin

Scott Arthur MacDonald

Frederick Hayes Dill

Marie-Claire Cyrille

Honglin Zhu

Virgil S Speriosu

Dennis R Wilhoit

The invention provides a tunneling magnetoresistance (TMR) read sensor with a long diffusion path and ex-situ interfaces in a sense layer structure. The sense layer structure comprises a first sense layer preferably formed of a ferromagnetic Co&#x2014;Fe film, a second sense layer preferably formed of a ferromagnetic Co&#x2014;Fe&#x2014;B film, and a third sense layer preferably formed of a ferromagnetic Ni&#x2014;Fe film. The sense layer structure has a long diffusion path (defined as a total thickness of the first and second sense layers) and ex-situ interfaces for suppressing unwanted diffusions of Ni atoms. Alternatively, the sense layer structure comprises a first sense layer preferably formed of a ferromagnetic Co&#x2014;Fe film, a second sense layer preferably formed of a ferromagnetic Co&#x2014;Fe&#x2014;B film, a third sense layer preferably formed of a ferromagnetic Co&#x2014;Fe&#x2014;B&#x2014;Hf film, and a fourth sense layer preferably formed of a ferromagnetic Ni&#x2014;Fe film.

Tunneling magnetoresistance (TMR) read sensor with a long diffusion path and ex-situ interfaces in a sense layer structure

The invention provides a tunneling magnetoresistance (TMR) read sensor with an integrated auxiliary shield comprising buffer, parallel-coupling, shielding and decoupling layers for high-resolution magnetic recording. The buffer layer, preferably formed of an amorphous ferromagnetic Co&#x2014;X (where X is Hf, Y, Zr, etc.) film, creates microstructural discontinuity between a lower ferromagnetic shield and the TMR read sensor. The parallel-coupling layer, preferably formed of a polycrystalline nonmagnetic Ru film, causes parallel coupling between the buffer and shielding layers. The shielding layer, preferably formed of a polycrystalline ferromagnetic Ni&#x2014;Fe film exactly identical to that used as the lower ferromagnetic shield, shields magnetic fluxes stemming from a recording medium into the lower edge of the TMR read sensor. The decoupling layer, preferably formed of another polycrystalline nonmagnetic Ru film, causes decoupling between the shielding layer and a pinning layer preferably formed of a polycrystalline antiferromagnetic Ir&#x2014;Mn film.

Tunneling magnetoresistance (TMR) read sensor with an integrated auxilliary ferromagnetic shield

The invention provides a bottom-type perpendicular magnetic tunnel junction (pMTJ) element with thermally stable amorphous blocking layers for high-density nonvolatile data storage. The first blocking layer, preferably formed of an amorphous nonmagnetic film, blocks a polycrystalline diffusion barrier layer with a body-center-cubic (bcc) &#x3c;110&#x3e; texture in order for the keeper and lower reference layers of the bottom-type pMTJ element to freely grow with a face-centered-cubic (fcc) &#x3c;111&#x3e; texture, thereby developing strong perpendicular magnetic anisotropy (PMA). The second blocking layer, preferably formed of an amorphous ferromagnetic film, blocks the keeper and lower reference layers of the bottom-type pMTJ element in order for the upper reference, barrier and storage layers of the bottom-type pMTJ element to freely grow with a &#x3c;001&#x3e; texture, thereby exhibiting a strong tunneling magnetoresistance (TMR) effect.

Bottom-type perpendicular magnetic tunnel junction (pMTJ) element with thermally stable amorphous blocking layers

A current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with dual seed and cap layers for high-resolution magnetic recording is provided by the invention. The dual seed layers comprise a lower seed layer preferably formed of a nonmagnetic Pt film and an upper seed layer preferably formed of a nonmagnetic Ru film. The lower seed layer separates the upper seed layer from a buffer layer preferably formed of a ferromagnetic Co&#x2014;Hf film, in order to minimize moment losses at its lower interface and thus define a sharp lower bound of a read gap. In addition, the lower seed layer facilitates the CPP read sensor to exhibit high pinning properties, while the upper seed layer facilitates the CPP read sensor to exhibit robust thermal properties.

Current-perpendicular-to-plane (CPP) read sensor with dual seed and cap layers

The present invention generally relates to a TMR reader and a method for its manufacture. The TMR reader discussed herein adds a shield layer to the sensor structure. The shield layer is deposited over the capping layer so that the shield layer and the capping layer collectively protect the free magnetic layer within the sensor structure from damage during further processing. Additionally, the hard bias layer is shaped such that the entire hard bias layer underlies the hard bias capping layer so that a top lead layer is not present. By eliminating the top lead layer and including a shield layer within the sensor structure, the read gap is reduced while still protecting the free magnetic layer during later processing.

TMR reader structure having shield layer

A current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with ferromagnetic buffer, shielding and seed layers is proposed for high-resolution magnetic recording. The ferromagnetic buffer layer is preferably formed of an amorphous Co&#x2014;X (where X is Hf, Y, Zr, etc.) film. It provides the CPP read sensor with microstructural discontinuity from a ferromagnetic lower shield, thus facilitating the CPP read sensor to grow freely with preferred crystalline textures, and with ferromagnetic continuity to the ferromagnetic lower shield, thus acting as a portion of the ferromagnetic lower shield. The ferromagnetic shielding layer is preferably formed of a polycrystalline Ni&#x2014;Fe film. It exhibits magnetic properties exactly identical to those of the ferromagnetic lower shield, thus acting identically as the ferromagnetic lower shield, and a uniform columnar grain morphology, thus initiating a uniform large grain morphology in the CPP read sensor.

Current-perpendicular-to-plane (CPP) read sensor with ferromagnetic buffer, shielding and seed layers

A current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with ferromagnetic buffer and seed layers is proposed for high-resolution magnetic recording. The ferromagnetic buffer layer is preferably formed of an amorphous Co&#x2014;X (where X is Hf, Y, Zr, etc.) film. It provides the CPP read sensor with microstructural discontinuity from a ferromagnetic lower shield, thus facilitating the CPP read sensor to grow freely with preferred crystalline textures, and with ferromagnetic continuity to the ferromagnetic lower shield, thus acting as a portion of the ferromagnetic lower shield.

Current-perpendicular-to-plane (CPP) read sensor with ferromagnetic buffer and seed layers

A magnetic structure in one embodiment includes a tunnel barrier layer; a free layer; and a buffer layer between the tunnel barrier layer and the free layer, wherein a cross sectional area of the tunnel barrier layer in a direction parallel to a plane of deposition thereof is greater than a cross sectional area of the free layer in a direction parallel to a plane of deposition thereof, wherein a cross sectional area of the buffer layer in a direction parallel to a plane of deposition thereof is greater than a cross sectional area of the free layer in the direction parallel to the plane of deposition thereof. Additional systems and methods are also presented.

Low resistance tunnel magnetoresistance (TMR) structure

A system in one approach includes a sensor stack formed of a plurality of thin film layers; a shunt formed of at least some of the same layers as the sensor stack, the shunt being spaced from the sensor stack; a first lead coupled to the sensor stack and the shunt; and a second lead coupled to the sensor stack and the shunt. A method in one embodiment includes forming a plurality of thin film layers; removing a portion of the thin film layers for defining at least a portion of a sensor stack and at least a portion of a shunt spaced front the sensor stack; forming a first lead coupled to the at least a portion of the sensor stack and the at least a portion of the shunt and a second lead coupled to the at least a portion of the sensor stack and the at least a portion of the shunt. Additional systems and methods are also presented.

Methods and systems for using resistivity of sensor film in an element shunt

A tunneling magnetoresistance (TMR) read sensor with a Co&#x2014;Fe&#x2014;B lower sense layer and a Co&#x2014;Hf upper sense layer is disclosed. In order for the dual sense layers to exhibit a negative saturation magnetostriction (&#x3bb;), their Fe contents are either substantially reduced or even eliminated, instead of adding a conventional Ni&#x2014;Fe film as an additional sense layer. By optimizing compositions and thicknesses of the dual sense layers, the dual sense layers indeed exhibit a negative &#x3bb;, while the TMR sensor exhibits a TMR coefficient (&#x394;R/R) of greater than 80% at a junction resistance-area product (RA) of less than 2 &#x3a9;-&#x3bc;m.

Tunneling magnetoresistance read sensor with dual sense layers

A narrow track-width magnetoresistive sensor by defining a trench formed between first and second hard bias layers and depositing the sensor into the trench. The sensor can include a sensor stack sandwiched between first and second electrically conductive lead layers. First and second electrically insulating side walls are formed at either side of the sensor stack. First and second hard bias layers extend from the sides of the sensor stack, being separated from the sensor stack by the first and second electrically insulating side walls. First and second physically hard insulation layers are provided over each of the hard bias layers.

Magnetic sensor having a physically hard insulation layer over a magnetic bias structure

A current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with ferromagnetic amorphous buffer and polycrystalline seed layers is disclosed for reducing a read gap, in order to perform magnetic recording at higher linear densities. The ferromagnetic amorphous buffer and polycrystalline seed layers couples to a ferromagnetic lower shield, thus acting as part of the ferromagnetic lower shield and defining the upper surface of the ferromagnetic polycrystalline seed layer as the lower bound of the read gap. In addition, a CPP TMR or GMR read sensor with nonmagnetic and ferromagnetic cap layers is also disclosed for reducing the read gap, in order to perform magnetic recording at even higher linear densities. The ferromagnetic cap layer couples to a ferromagnetic upper shield, thus acting as part of the ferromagnetic upper shield and defining the lower surface of the ferromagnetic cap layer as the upper bound of the read gap.

Current-perpendicular-to-plane (CPP) read sensor with ferromagnetic amorphous buffer and polycrystalline seed layers

The invention provides a current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with multiple ferromagnetic sense layers. In one embodiment of the invention, a CPP TMR read sensor comprises a first sense layer formed by a ferromagnetic polycrystalline Co&#x2014;Fe film, a second sense layer formed by a ferromagnetic interstitial-type amorphous Co&#x2014;Fe&#x2014;B film, a third sense layer formed by a ferromagnetic substitute-type amorphous Co&#x2014;Fe&#x2014;X film where X is Hf, Zr or Y, and a fourth sense layer formed by a ferromagnetic Ni&#x2014;Fe film. The third sense layer acts as a diffusion barrier layer to suppress Ni diffusion, thus allowing the incorporation of the Ni&#x2014;Fe fourth sense layer for improving ferromagnetic properties of the multiple sense layers. The multiple sense layers induce spin-dependent scattering, thus facilitating the CPP TMR read sensor to exhibit a strong TMR effect.

Current-perpendicular-to-plane (CPP) read sensor with multiple ferromagnetic sense layers

A dual magnetic tunnel junction (MTJ) sensor is provided with a longitudinal bias stack sandwiched between a first MTJ stack and a second MTJ stack. The longitudinal bias stack comprises an antiferromagnetic (AFM) layer sandwiched between first and second ferromagnetic layers. The first and second MTJ stacks comprise antiparallel (AP)-pinned layers pinned by AFM layers made of an AFM material having a higher blocking temperature than the AFM material of the bias stack allowing the AP-pinned layers to be pinned in a transverse direction and the bias stack to be pinned in a longitudinal direction. The demagnetizing fields of the two AP-pinned layers cancel each other and the bias stack provides flux closures for the sense layers of the first and second MTJ stacks.

Dual magnetic tunnel junction sensor with a longitudinal bias stack

A current-to-perpendicular-to-plane (CPP) read sensor with multiple reference layers and associated fabrication methods are disclosed. According to one embodiment of the invention, the multiple reference layers of a CPP tunneling magnetoresistance (TMR) read sensor includes a first reference layer formed by a ferromagnetic polycrystalline Co&#x2014;Fe film, a second reference layer formed by a ferromagnetic substitute-type amorphous Co&#x2014;Fe&#x2014;X film where X is Hf, Zr or Y, and a third reference layer formed by a ferromagnetic interstitial-type amorphous Co&#x2014;Fe&#x2014;B film. The first reference layer facilitates the CPP TMR read sensor to exhibit high exchange and antiparallel-coupling fields. The second reference layer provides a thermally stable flat surface, thus facilitating the CPP TMR read sensor to exhibit a low ferromagnetic-coupling field. The multiple reference layers may induce spin-dependent scattering, thus facilitating the CPP TMR sensor to exhibit a high TMR coefficient.

Current-perpendicular-to-plane (CPP) read sensor with multiple reference layers

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Saratoga, CA, United States of America

Tsann Lin