Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Adam Polcyn

Xiaoping Bian

Mary Frances Doerner

Kai Tang

Mohammad Taghi Mirzamaani

Vladimir Nikitin

Tim Minvielle

Bernd Lamberts

Tetsuya Kanbe

James Aloysius Hagan

Qi-Fan Xiao

William Harlow McConnell

Mark F Mercado

Wenchien David Hsiao

Frank J Wang

Mohammad S Mirzamaani

An antiferromagnetically coupled (AFC) magnetic recording medium with an AFC master layer comprising at least two magnetic layers with the top magnetic layer including copper is described. The slave layer is separated from the master layer structure by a nonmagnetic spacer layer selected to antiferromagnetically couple the layers. The master layer structure according to the invention includes a bottom and top layer of distinct ferromagnetic materials. Preferably, the top layer of the master layer is a cobalt alloy including from 1 to 5 at. % copper with an example being CoPtCrBCu. The AFC magnetic layer structure can be used with a variety of substrates including circumferentially textured glass and NiP/AlMg.

Magnetic recording disk with antiferromagnetically coupled master layer including copper

A method of longitudinal recording using a medium with a magnetically soft underlayer is described. The method includes lowering the longitudinal coercivity in a magnetic domain in the magnetic recording medium by generating a vertical component of magnetic flux in the magnetic recording medium and writing a longitudinal orientation in the magnetic domain in the magnetic recording medium by generating a larger horizontal component of magnetic flux in the magnetic recording medium using the write head. Optionally the method further includes magnetically saturating the magnetically soft underlayer after lowering the longitudinal coercivity to limit the vertical component of the magnetic flux. The recording medium has a magnetic recording layer, a spacer layer and a soft underlayer. In one embodiment the soft underlayer is an antiferromagnetically coupled magnetic layer stack with two soft magnetic layers separated by a non-magnetic spacer layer selected to achieve the antiferromagnetic coupling.

Longitudinal magnetic recording using magnetic media with a soft underlayer

Provided are a method, system, and program for performing error correction in a storage device having a magnetic storage medium. A plurality of zones are defined in the magnetic storage medium, wherein each zone comprises a plurality of addressable locations in the magnetic storage medium. A determination is made as to whether a change of a signal-to-noise ratio for one subject zone of the plurality of zones exceeds a threshold. An operation is performed to improve the signal-to-noise ratio with respect to the subject zone of the magnetic storage medium after determining that the change of the signal-to-noise ratio exceeds the threshold.

Method, system, and program for performing error correction in a storage device having a magnetic storage medium

A thin film magnetic media structure with a bi-layer structure of amorphous chromium titanium (CrTi) followed by an amorphous layer of nickel phosphorus (NiP) is disclosed. After the NiP has been deposited it is exposed to oxygen to form an oxidized surface. Preferably the underlayer is deposited directly onto the oxidized NiP surface. The bi-layer structure of CrTi/NiP promotes excellent in-plane crystallographic orientation in the cobalt alloy magnetic layer(s) and allows an ultra-thin chromium underlayer to be used which provides better control over grain size and distribution. When the CrTi/NiP bi-layer structure is combined with a circumferentially textured substrate, preferably glass, a high Mrt orientation ratio (OR) results.

Magnetic thin film media with a bi-layer structure of CrTi/Nip

A thin film magnetic media structure with a pre-seed layer of CrTi is disclosed. The CrTi pre-seed layer presents an amorphous or nanocrystalline structure. The preferred seed layer is RuAl for use with the CrTi pre-seed layer. The use of the CrTi/RuAl bilayer structure provides superior adhesion to the substrate and resistance to scratching, as well as, excellent coercivity and signal-to-noise ratio (SNR) and reduced cost over the prior art. One embodiment of the invention sputter-deposits a CrTi pre-seed layer and a RuAl seed layer followed by at least one underlayer and at least one magnetic layer on a circumferentially polished substrate structure to achieve an Mrt orientation ratio greater than one. Two methods according to the invention allow the Mrt orientation ratio of the disk to be adjusted or maximized by varying the thickness of the RuAl seed layer and/or altering the atomic percentage of titanium in the pre-seed layer.

Magnetic thin film media with a pre-seed layer of CrTi

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San Jose, CA, United States of America

Adam Polcyn