Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Hgst Netherlands, B.v.

Hitachi Global Storage Technologies

Ernesto Esteban Marinero

Bruce Alvin Gurney

Brian Rodrick York

Thomas Dudley Boone, Jr

Dieter Klaus Weller

David Thomas Margulies

Robert Fontana

Stefan Maat

Neil Smith

Olav Hellwig

Timothy Martin Reith

Simone Pisana

Hal Jervis Rosen

Eric Edward Fullerton

Manfred Ernst Schabes

Prakash Kasiraj

David Arfon Williams

James Lamar Nix

Amitava Chattopadhyay

Thomas R Albrecht

Zvonimir Z Bandic

Kuok San Ho

Hemantha Kumar Wickramasinghe

Kurt A Rubin

Jordan Asher Katine

Michael Grobis

Meng Ding

Marie-Claire Cyrille

Liesl Folks

Byron Hassberg Lengsfield, Iii

Joerg Wunderlich

Andrew Stuart Troup

Hal Jerves Rosen

Glen Alan Jaquette

Bruce Alexander Wilson

Richard Hsiao

Bruce David Terris

Hugo Alberto Emilio Santini

Ricardo Ruiz

Xiaoping Bian

Mohammad Taghi Mirzamaani

Yoshihiro Ikeda

Natacha Frederique Supper

Blair I Finkelstein

Dan Saylor Kercher

Andreas Klaus Berger

David E Call

Gabriel Zeltzer

Patrick C Arnett

Hermantha K Wickramasinghe

Jack Chang

Andrew Thomas McCallum

Aleksey Andreev

Kuok-San Ho

Andreas K Berger

A magnetic disk according to one embodiment includes a recording layer; and a layer of graphene formed above the recording layer. A nucleation layer may be formed between the recording layer and the graphene layer in some approaches. A magnetic device according to another embodiment includes a transducer; a nucleation layer formed above the transducer; and a layer of graphene formed on the nucleation layer. A method according to one embodiment includes forming a nucleation layer above a magnetic layer of a magnetic disk or magnetic device; and forming a layer of graphene on the nucleation layer. A method according to another embodiment includes depositing SiC above a magnetic layer of a magnetic disk or magnetic device, the SiC being equivalent to several monolayers thick; and surface heating the SiC to selectively evaporate some of the Si from the SiC for forming a layer of graphene on a SiC layer. Additional products and methods are also presented.

Magnetic devices and magnetic media with graphene overcoat

A method for making a bit-patterned-media magnetic recording disk with discrete magnetic islands includes annealing the data islands after they have been formed by an etching process. A hard mask, such as a layer of silicon nitride or carbon, may be first formed on the recording layer and a patterned resist formed on the hard mask. The resist pattern is then transferred into the hard mask, which is used as the etch mask to etch the recording layer and form the discrete data islands. After the data islands are formed by the etching process, the patterned recording layer is annealed. The annealing may be done in a vacuum, or in an inert gas, like helium or argon, or in a forming gas such as a reducing atmosphere of argon plus hydrogen. The annealing improves the coercivity, the effective saturation magnetization and the thermal stability of the patterned media.

Method for improving a patterned perpendicular magnetic recording disk with annealing

Methods of fabricating perpendicular magnetic recording media are disclosed. The multilayer structures of the perpendicular magnetic recording media are fabricated by varying the sputtering conditions (i.e., pressure, sputtering gas, etc) in a single sputtering module so that multiple sputtering modules are not needed to form the multilayer structures. These fabrication methods allow sputtering tools with a limited number of chambers, which were designed for the manufacture of longitudinal media, to be used to efficiently produce perpendicular media architectures which heretofore required a large number of sputtering modules. It is further shown that media structures involving a geometric weak-link architecture are suited for these fabrication techniques.

Generation of multilayer structures in a single sputtering module of a multi-station magnetic recording media fabrication tool

A perpendicular magnetic recording disk has a graded-anisotropy recording layer (RL) formed of at least two ferromagnetically exchange coupled CoPtCr-oxide magnetic layers (MAG1 and MAG2) with two nucleation films (NF1 and NF2) between the magnetic layers. NF1 is a metal film, preferably Ru or a Ru-based alloy like RuCr, sputter deposited on MAG1 at low pressure to a thickness between about 0.1-1.5 nm. NF2 is a metal oxide film, preferably an oxide of Ta, sputter deposited on NF1 at high pressure to a thickness between about 0.2-1.0 nm. MAG2 is sputter deposited over NF2. NF1 and NF2 provide a significant reduction in average grain size in the RL from a graded-anisotropy RL without nucleation films between MAG1 and MAG2, while also assuring that MAG1 and MAG2 are strongly exchange coupled.

Perpendicular magnetic recording disk with multiple magnetic layers and intermediate dual nucleation films for control of grain size

An electrical circuit structure employing graphene as a charge carrier transport layer. The structure includes a plurality of graphene layers. Electrical contact is made with one of the layer of the plurality of graphene layers, so that charge carriers travel only through that one layer. By constructing the active graphene layer within or on a plurality of graphene layers, the active graphene layer maintains the necessary planarity and crystalline integrity to ensure that the high charge carrier mobility properties of the active graphene layer remain intact.

Method for manufacturing graphene electronics

An electronic device employing a graphene layer as a charge carrier layer. The graphene layer is sandwiched between layers that are constructed of a material having a highly ordered crystalline structure and a high dielectric constant. The highly ordered crystalline structure of the layers surrounding the graphene layer has low density of charged defects that can lead to scattering of charge carriers in the graphene layer. The high dielectric constant of the layers surrounding the graphene layer also prevents charge carrier scattering by minimizing interaction between the charge carriers and the changed defects in the surrounding layers. An interracial layer constructed of a thin, non-polar, dielectric material can also be provided between the graphene layer and each of the highly ordered crystalline high dielectric constant layers to minimize charge carrier scattering in the graphene layer through remote interfacial phonons.

Quantum well graphene structure formed on a dielectric layer having a flat surface

A device for sensing a magnetic field is described. The device comprises first, second and third leads and a junction between the leads. The junction and leads are arranged in a plane and the junction is configured to exhibit quantum confinement in a direction perpendicular to the plane. The first lead is arranged on one side of the junction and the second and third leads are arranged on an opposite side of the junction. The first lead is configured to limit angle of spread of charge carriers entering the junction so that, when charge carriers flow into the junction from the first lead, the charge carriers form a substantially nondivergent beam.

Magnetic field sensor

A patterned perpendicular magnetic recording disk with discrete data islands of recording layer (RL) material includes a substrate, a patterned exchange bridge layer of magnetic material between the substrate and the islands, and an optional exchange-coupling control layer (CCL) between the exchange bridge layer and the islands. The exchange bridge layer has patterned pedestals below the islands. The exchange bridge layer controls exchange interactions between the RLs in adjacent islands to compensate the dipolar fields between islands, and the pedestals concentrate the flux from the write head. The disk may include a soft underlayer (SUL) of soft magnetically permeable material on the substrate and a nonmagnetic exchange break layer (EBL) on the SUL between the SUL and the exchange bridge layer. In a thermally-assisted recording (TAR) disk a heat sink layer may be located below the exchange bridge layer and the SUL may be optional.

Patterned perpendicular magnetic recording disk drive and medium with patterned exchange bridge layer below the data islands

A patterned perpendicular magnetic recording medium has discrete data islands that have first and second ferromagnetic layers (MAGand MAG) with first and second nonmagnetic interlayers (ILand IL) between MAGand MAG. MAGand MAGmay be similar CoPtCr alloys with similar thicknesses, with thicknesses of ILand ILthat assure that MAGand MAGare strongly exchange coupled. Alternatively, MAGmay be a 'write assist' layer, for example a high-saturation magnetization, magnetically soft material in an exchange-spring structure, with ILbeing very thin so that ILfunctions as the coupling layer between MAGand the write-assist MAGlayer. In an application for thermally-assisted recording (TAR), MAGmay be the chemically-ordered equiatomic binary alloy FePt or CoPt based on the Lphase, with high magneto-crystalline anisotropy (K).

Patterned perpendicular magnetic recording medium with multiple magnetic layers and interlayers

A Lorentz Magnetoresistive sensor having an ultrathin trapping layer disposed between a quantum well structure and a surface of the sensor. The trapping layer prevents charge carriers from the surface of the sensor from affecting the quantum well structure. This allows the quantum well structure to be formed much closer to the surface of the sensor, and therefore, much closer to the magnetic field source, greatly improving sensor performance. A Lorentz Magnetoresistive sensor having a top gate electrode to hinder surface charge carriers diffusing into the quantum well, said top gate electrode being either a highly conductive ultrathin patterned metal layer or a patterned monoatomic layer of graphene.

Magnetoresistive sensor having a quantum well structure and a P-doped trapping layer to prevent surface charge carriers from migrating to the quantum well structure

A patterned perpendicular magnetic recording disk has a Co-alloy recording layer patterned into discrete data islands arranged in concentric tracks and exhibits a narrow switching field distribution (SFD). The disk includes a substrate, a NiTa alloy planarizing layer on the substrate, a nonmagnetic Ru-containing underlayer on the planarizing layer, an oxide-free Co alloy magnetic recording layer, and an ultrathin oxide film between the Ru-containing layer and the Co-alloy magnetic recording layer. The oxide film may be an oxide selected from a Ta-oxide, a Co-oxide and a Ti-oxide, and is ultrathin so that it may be considered a discontinuous film. The planarizing layer and ultrathin oxide film improve the growth homogeneity of the Co-alloy recording layer, so that the patterned disk with data islands shows significantly reduced SFD.

Patterned perpendicular magnetic recording medium with ultrathin oxide film and reduced switching field distribution

An electronic device employing a graphene layer as a charge carrier layer. The graphene layer is sandwiched between layers that are constructed of a material having a highly ordered crystalline structure and a high dielectric constant. The highly ordered crystalline structure of the layers surrounding the graphene layer has low density of charged defects that can lead to scattering of charge carriers in the graphene layer. The high dielectric constant of the layers surrounding the graphene layer also prevents charge carrier scattering by minimizing interaction between the charge carriers and the charged defects in the surrounding layers. An interracial layer constructed of a thin, non-polar, dielectric material can also be provided between the graphene layer and each of the highly ordered crystalline high dielectric constant layers to minimize charge carrier scattering in the graphene layer through remote interfacial phonons.

Quantum well graphene structure

Graphene electronics fabrication

A graphene magnetic field sensor has a ferromagnetic biasing layer located beneath and in close proximity to the graphene sense layer. The sensor includes a suitable substrate, the ferromagnetic biasing layer, the graphene sense layer, and an electrically insulating underlayer between the ferromagnetic biasing layer and the graphene sense layer. The underlayer may be a hexagonal boron-nitride (h-BN) layer, and the sensor may include a seed layer to facilitate the growth of the h-BN underlayer. The ferromagnetic biasing layer has perpendicular magnetic anisotropy with its magnetic moment oriented substantially perpendicular to the plane of the layer. The graphene magnetic field sensor based on the extraordinary magnetoresistance (EMR) effect may function as the magnetoresistive read head in a magnetic recording disk drive.

Magnetic field sensor with graphene sense layer and ferromagnetic biasing layer below the sense layer

A method for manufacturing an extraordinary magnetoresistive sensor (EMR sensor) having reduced size and increased resolution is described. The sensor includes a plurality of electrically conductive leads contacting a magnetically active layer and also includes an electrically conductive shunt structure. The electrically conductive leads of the sensor and the shunt structure can be formed in a common photolithographic masking and etching process so that they are self aligned with one another. This avoids the need to align multiple photolithographic processing steps, thereby allowing greatly increased resolution and reduced lead spacing. The EMR sensor can be formed with a magnetically active layer that can be close to or at the air bearing surface (ABS) for improved magnetic spacing with an adjacent magnetic medium of a data recording system.

Method for manufacturing an extraordinary magnetoresistive (EMR) device with novel lead structure

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Saratoga, CA, United States of America

Ernesto Esteban Marinero