Hmt Technology Corporation

Brij B Lal

Tadashi Shinohara

Michael A Russak

Allen J Bourez

Atef H Eltoukhy

Sudhir S Malhotra

James L Chao

Lan Zhang

A magnetic recording medium having a dual underlayer structure is described. The underlayer structure is composed of a first underlayer of chromium and a second underlayer of a chromium alloy.

Longitudinal recording medium with a dual underlayer

A longitudinal magnetic recording medium having a CrTi underlayer deposited under a substrate bias is described. The medium has improved magnetic recording properties.

Magnetic recording media having a CrTi underlayer deposited under a substrate bias

A magnetic recording medium having a barrier layer deposited directly on the magnetic recording layer is described. The barrier layer is deposited by sputter deposition under a nitrogen-containing sputtering atmosphere to form a nitrogen-containing chromium or chromium alloy barrier layer. The barrier layer is effective to inhibit migration of cobalt from the underlying magnetic recording layer, reducing corrosion of the medium and improving magnetic recording performance.

Magnetic recording medium having a nitrogen-containing barrier layer

An improvement in a magnetic recording medium having an underlayer and first and second magnetic recording layers is described. The improvement, effective to reduce media noise, includes deposition of an interlayer between the first and second magnetic recording layers. The interlayer is deposited to a thickness of between 5-50 .ANG. and is composed of an CoCr-based alloy having a defined saturation magnetization.

Magnetic recording medium having a multilayer magnetic recording

An improvement in a magnetic recording medium having an underlayer and a magnetic layer is described. The improvement, effective to increase the coercivity of the medium, includes deposition of an interlayer between the underlayer and the magnetic recording layer. The interlayer is deposited to a thickness of between 10-60 .ANG. and is composed of an CoCr-based alloy having a defined saturation magnetization.

Magnetic recording medium having a CoCr alloy interlayer of a low

An improvement in a magnetic recording medium having an underlayer and a magnetic recording layer is described. The improvement, effective to reduce media anisotropy, includes deposition of a prelayer on the substrate, prior to deposition of the underlayer. The prelayer is deposited to a thickness of between 10-60 .ANG. and is composed of an CoCr-based alloy having a defined saturation magnetization.

Magnetic recording medium having a prelayer

A bilayer magnetic recording medium having first and second magnetic recording layers separated by a nonmagnetic isolation layer is disclosed. The medium is characterized by a high coercivity, low noise and an improved overwrite. In producing the medium, the second magnetic layer is deposited under sputtering conditions effective to produce a higher coercivity.

Multilayered magnetic recording medium with coercivity gradient

A magnetic thin-film medium characterized by high coercivity, loop squareness, and signal-to-noise ratio characteristics. The medium includes a disc-like substrate, a sputtered Cr underlayer having a thickness between 100-300 .ANG., and a sputtered Co alloy magnetic thin-film layer having a thickness between 250-800 .ANG.. The sputtered Cr and magnetic layers are preferably formed under sputtering conditions in which a negative bias of between -50 to -600 volts is applied to the substrate.

Thin-film recording medium with thin chromium underlayer

A low-noise, thin-film magnetic recording medium, and method of making the same, are disclosed. The medium has a multilayer magnetic-film construction, where the individual magnetic-film layers are isolated by a thin ferromagnetic film. The ferromagnetic layer is effective to reduce the medium noise and increase medium signal-to-noise ratio at least as much as a Cr isolation having the same isolation-layer thickness, but with substantially less reduction in overwrite.

Multilayer magnetic medium with soft magnetic interlayer

A target assembly for use in forming a protective overcoat in a magnetic recording medium is described. The assembly includes a centrally positioned target with inner and outer magnetic means adjacent the target. A sputtering shield is positioned between the target and the medium for controlling the amount and angle of material deposition on the medium. The assembly is effective to deposit an overcoat having a greater thickness in the inner landing zone of the medium than in the outer data zone. A method of using the assembly is also disclosed.

Target assembly for use in forming an overcoat in a magnetic recording

A method for forming an overcoat having first and second layers in a magnetic recording medium is described. The first overcoat layer is deposited in a first sputtering chamber where the magnetic means for confining target plasma in the chamber are oriented to retain magnetic-field confinement about the target surface and to produce magnetic field lines between directly confronting portions of the confronting sputtering targets. The second overcoat layer is deposited under a nitrogen-containing atmosphere.

Method for forming a thin carbon overcoat in a magnetic recording medium

A method of producing a magnetic recording medium by sputtering a layer onto a substrate by DC-magnetron sputtering from a target while exposing the target to an RF signal is described. The RF signal is effective to extend the target utilization without significantly decreasing the sputtering rate. Also disclosed is an apparatus for use forming a medium in accordance with the method of the invention.

DC magnetron sputtering method and apparatus

A method for forming a magnetic recording medium having a chromium underlayer and a magnetic recording layer is described. The method includes sputtering the underlayer and the magnetic layer in a single sputtering chamber from a two-region target having an inner chromium region and an outer magnetic region. Each target region is successively energized for sputter deposition of each layer.

Method of producing a magnetic recording medium

A cathode assembly having a magnetic-field shunt for use in a magnetron sputtering apparatus is described. The magnetic-field shunt disposed between a sputtering target and a source of magnetic flux, and the shunt is moveable between first and second positions to effect preferential target erosion at first and second target regions, respectively. A method of using the assembly for preparation of a magnetic recording medium is also described.

Cathode assembly having rotating magnetic-field shunt and method of

A thin-film multilayered recording medium is disclosed. The medium contains two or more magnetic thin-film sublayers separated by an isolation layer having an axial composition gradient.

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San Jose, CA, United States of America

Brij B Lal