Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Hgst Netherlands, B.v.

Hoa Van Do

David Thomas Margulies

Eric Edward Fullerton

Natacha Frederique Supper

Yoshihiro Ikeda

Kentaro Takano

Andreas Klaus Berger

Qing Dai

Hal Jervis Rosen

Min Xiao

Xiaoping Bian

Bruce Alvin Gurney

Matthew Joseph Carey

Tim Minvielle

Mary Frances Doerner

Andreas Moser

James Aloysius Hagan

Philip M Rice

Byron Hassberg Lengsfield, Iii

Timothy Martin Reith

Ronald Franklin Marks

Ren Xu

Jack Jyh-Kau Chang

Chu S Tran

Bernd Heinz

Robin Frederick Charles Farrow

Bruno Jean Marchon

Bruce David Terris

Manfred Ernst Schabes

Kai Tang

Bing K Yen

Qing Zhu

Qi-Fan Xiao

Mary Frances Minardi

Yoshiaki Sonobe

Sylvia Helena Florez

William G McChesney

In one general embodiment, a magnetic medium includes a recording layer having at least three exchange control layers each having a magnetic moment less than 100 emu/cc, and four magnetic layers separated from one another by the exchange control layers. An uppermost of the magnetic layers is doped with oxygen. In another general embodiment, a magnetic medium includes a recording layer having at least three exchange control layers and four magnetic layers separated from one another by the exchange control layers. An uppermost of the magnetic layers has an oxygen content of greater than 0.5 vol %. An average pitch of magnetic grains in a lowermost of the magnetic layers is 9 nm or less. A lowermost of the magnetic layers has an oxide content of at least 20 vol %.

Vertically and horizontally weakly coupled perpendicular small grain media

A method according to one embodiment includes forming a high Ku first oxide magnetic layer above a substrate by sputtering; forming a low Ku second oxide magnetic layer above the first oxide magnetic layer by sputtering; forming an exchange coupling layer of CoCrPt-oxide above the second oxide magnetic layer; and forming a magnetic cap layer above the exchange coupling layer. Additional systems and methods are also presented.

Perpendicular magnetic recording media with oxide-containing exchange coupling layer

A laminated magnetic recording structure for use in perpendicular or longitudinal recording is described. A small amount of ferromagnetic coupling is added between the two magnetic layers that are sufficiently decoupled to switch independently. In one embodiment the coupling is achieved by doping the spacer layer with a ferromagnetic material. Ruthenium (Ru), which is a preferred nonmagnetic material for spacer layers with cobalt (Co) being the preferred magnetic material. The weak ferromagnetic coupling can also be achieved through the use of platinum, palladium and alloys thereof for the spacer layer without the addition of a ferromagnetic element, but alternatively they can also be doped with ferromagnetic elements. For embodiments for perpendicular recording the spacer layer further can additionally comprise oxides of one or more elements selected from the group consisting of Si, Ta, Ti, Nb, Cr, V and B.

Laminated magnetic thin films for magnetic recording with weak ferromagnetic coupling

A magnetic storage medium according to one embodiment includes a substrate; a first oxide magnetic layer formed above the substrate; a second oxide magnetic layer formed above the first oxide magnetic layer; an exchange coupling layer formed above the second oxide magnetic layer, the exchange coupling layer comprising an oxide; and a magnetic cap layer formed above the exchange coupling layer. A method according to one embodiment includes forming a high Ku first oxide magnetic layer above a substrate by sputtering; forming a low Ku second oxide magnetic layer above the first oxide magnetic layer by sputtering; forming an exchange coupling layer of CoCrPt-oxide above the second oxide magnetic layer; and forming a magnetic cap layer above the exchange coupling layer. Additional systems and methods are also presented.

A recording medium providing improved writeability in perpendicular recording applications includes a magnetic recording layer having an axis of magnetic anisotropy substantially perpendicular to the surface thereof, an exchange-spring layer ferromagnetically exchange coupled to the magnetic recording layer and having a coercivity less than the magnetic recording layer coercivity, and a coupling layer between the magnetic recording layer and the exchange-spring layer. The coupling layer regulates the ferromagnetic exchange coupling between the magnetic recording layer and the exchange-spring layer.

Perpendicular recording media having an exchange-spring structure

The invention includes a disk drive with a magnetic recording disk with an upper and lower sublayer in at least one magnetic layer of a laminated magnetic layer structure that includes a spacer layer that substantially decouples the magnetic layers. The lower sublayer has a lower boron content than the upper sublayer and a preferred embodiment is CoPtCrBTa. The upper sublayer is deposited onto the lower sublayer and is preferably CoPtCrB with a higher boron content than the lower sublayer. The composition of the lower sublayer gives it a very low moment with low intrinsic coercivity which would not be useful as a recording layer on its own. The upper sublayer is a higher moment alloy with high intrinsic coercivity. An embodiment of the invention includes a laminated magnetic layer structure which is antiferromagnetically coupled to a lower ferromagnetic layer.

Disk drive with laminated magnetic thin films with sublayers for magnetic recording

A method for improving magnetic grain segregation in perpendicular recording media includes providing a substrate comprising a rigid support structure, depositing a soft underlayer on top of the substrate depositing an intermediate layer on top of the soft underlayer, providing a plurality of prospective segregants, determining the surface energies and the heat of formation of the prospective segregants and selecting the prospective segregant with a low surface energy and a high heat of formation. The method also includes providing at least one layer with surface energies progressively increasing to minimize the difference between the surface energy of a carbon overcoat and the segregant.

Apparatus, system, and method for the selection of perpendicular media segregant materials

An improved structure for the construction of perpendicular recording media is disclosed. The structure includes a perpendicular recording layer with at least two oxide sublayers or a lower sublayer of a non-oxide. One structure includes an upper sublayer comprised of a Silicon-oxide, while a lower sublayer is comprised of a Tantalum-oxide. The structures provide for increased coercivity and corrosion resistance.

Oxide magnetic recording layers for perpendicular recording media

A SiON overcoat for use on magnetic media for magnetic recording. The SiON overcoat is deposited by pulsed DC sputtering while applying a negative DC bias. The SiON overcoat is especially useful on perpendicular magnetic recording media because of its ability to deposit thinly and evenly on a rough, granular high coercivity recording media while maintaining excellent corrosion protection properties. A SiON overcoat can be applied less than 3 nm thick while still maintaining excellent mechanical and corrosion protection. The overcoat also has a very high density and water contact angle.

SiN overcoat for perpendicular magnetic recording media

A perpendicular magnetic recording system and medium has a multilayered recording layer that includes an exchange-spring structure and a ferromagnetic lateral coupling layer (LCL). The exchange-spring structure is made up of two ferromagnetically exchange-coupled magnetic layers (MAGand MAG), each with perpendicular magnetic anisotropy. MAGand MAGare either in direct contact with one another or have a coupling layer (CL) located between them. The LCL is located in direct contact with MAGand mediates intergranular exchange coupling in MAG. The ferromagnetic alloy in the LCL has significantly greater intergranular exchange coupling than the ferromagnetic alloy in MAG, which typically will include segregants such as oxides. The LCL is preferably free of oxides or other segregants, which would tend to reduce intergranular exchange coupling in the LCL. Because the LCL grain boundaries overlay the boundaries of the generally segregated and decoupled grains of MAG, and the LCL and MAGgrains are strongly coupled perpendicularly, the LCL introduces an effective intergranular exchange coupling in the MAG

Perpendicular magnetic recording medium with an exchange-spring recording structure and a lateral coupling layer for increasing intergranular exchange coupling

An embodiment of the invention is a layered magnetic thin film structure that uses antiferromagnetically coupled (AFC) magnetic layers where the top layer structure consists of an upper magnetic layer that is weakly ferromagnetically coupled via a nonmagnetic or weakly magnetic exchange coupling layer (interlayer) to a ferromagnetic exchange enhancing layer that is in turn, AF coupled to the lower ferromagnetic layer of the AFC structure. Preferred materials for the weak coupling layer include alloys of cobalt such as CoRu, CoBRu and CoCr in which the Co content is below the point at which the material would be ferromagnetic. A second embodiment of the invention is a laminated, AF-coupled media structure. In this structure the lower AFC layer that makes up the lower laminate layer includes: the middle magnetic layer, the weak ferromagnetic coupling layer, and the exchange enhancing layer.

Antiferromagnetically coupled media for magnetic recording with weak coupling layer

A perpendicular magnetic recording medium has an 'exchange-spring' type magnetic recording layer (RL) formed of two ferromagnetic layers with substantially similar anisotropy fields that are ferromagnetically exchange-coupled by a nonmagnetic or weakly ferromagnetic coupling layer. Because the write head produces a larger magnetic field and larger field gradient at the upper portion of the RL, while the field strength decreases further inside the RL, the upper ferromagnetic layer can have a high anisotropy field. The high field and field gradient near the top of the RL, where the upper ferromagnetic layer is located, reverses the magnetization of the upper ferromagnetic layer, which then assists in the magnetization reversal of the lower ferromagnetic layer. Because both ferromagnetic layers in this exchange-spring type RL have a high anisotropy field, the thermal stability of the medium is not compromised. The medium shows improved writability, i.e., a low switching field, as well as lower intrinsic media noise, over a medium with a conventional single-layer RL.

Perpendicular magnetic recording medium with multiple exchange-coupled magnetic layers having substantially similar anisotropy fields

A perpendicular magnetic recording medium, such as a perpendicular magnetic recording disk, has a magnetic 'torque' layer (MTL) that exerts a magnetic torque onto the perpendicular magnetic recording layer (RL) in the presence of the applied perpendicular write field. The MTL thus acts as a write assist layer in reversing the magnetization of the RL. A coupling layer (CL) is located between the MTL and the RL and provides the appropriate ferromagnetic coupling strength between the MTL and the RL.

Perpendicular magnetic recording medium with magnetic torque layer coupled to the perpendicular recording layer

A perpendicular magnetic recording disk has a granular Co-based ferromagnetic alloy recording layer (RL) with oxides of a selected metal (Ta or Nb) and a reduced-thickness exchange-break layer (EBL) between the RL and the soft magnetic underlayer (SUL). A perpendicular magnetic recording system that includes the disk, the write head and the read head, has an improved ability to write to the RL because of the reduced-thickness EBL.

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Fremont, CA, United States of America

Hoa Van Do