International Business Machines Corporation

Thomas J Beaulieu

Lubomyr Taras Romankiw

Daniel A Nepela

John Casimir Slonczewski

Bernell E Argyle

Sol Krongelb

Hin P Lee

Bojan Petek

Dean A Herman, Jr

Thomas C Arnoldussen

David John Seagle

Mohamad Towfik Krounbi

Joseph Adam Aboaf

Franklin T Plante

Robert H Tlaskal

Vincent Noel Kahwaty, Deceased

Michael A Marchese

A thin-film magnetic head includes a substrate having first and second magnetic layers disposed above the substrate and formed as a laminated sequence of magnetic sub-layers. The first and second magnetic layers have corresponding first ends representing a pole tip region of the head, corresponding second ends representing a back gap region of the head, and corresponding intermediate portions representing an intermediate region of the head between the pole tip region and the back gap region. The first and second magnetic layers are joined together in physical contact at the back gap region and are spaced from one another at the pole tip region and at the intermediate region. A nonmagnetic gap layer is disposed between the first and second magnetic layers at the pole tip region. A magnetic coil structure is disposed between the first and second magnetic layers at the intermediate region. The second magnetic layer has a sloped region wherein the second magnetic layer slopes away from the first magnetic layer behind the pole tip region to form a space for the magnetic coil structure. The sloped region of the second magnetic layer may have less magnetic permeability than other portions of the second magnetic layer. A third magnetic layer is thus disposed on the second magnetic layer and extends from the back gap region to cover at least the sloped region of the second magnetic layer.

Dual header tape head design

Magnetic thin film structures are disclosed including a laminate of a layer of nonmagnetic material sandwiched between first and second layers of magnetic material and at least one edge closure layer of magnetic material disposed on a side edge of the laminate with the edge closure layer being in magnetic contact with the first and second layers of magnetic material. The edge closure layer eliminates magnetic edge closure domains and magnetic edge-curling walls in the yoke and poletip regions, or in a fluxguide of a magnetic recording head to substantially eliminate Barkhausen noise and wall network instabilities. Multiple layer laminates are also disclosed having a plurality of nonmagnetic layers each of which are sandwiched between layers of magnetic material and wherein the laminate includes edge closure layers that contact all the magnetic layers. Several methods are disclosed for fabricating the laminate. In one class of technique, the side edges are deposited together with a top layer in a single plating operation. In an another embodiment, the side edge closure layers are separately plated. Another embodiment provides for a layer of antiferromagnetic material deposited between the nonmagnetic layer and one of the magnetic layers to provide additional anisotropy.

Magnetic thin film structures fabricated with edge closure layers

Magnetic thin film structures including a laminate of a layer of nonmagnetic material sandwiched between first and second layers of magnetic material and at least one edge closure layer of magnetic material disposed on a side edge of the laminate with the edge closure layer being in magnetic contact with the first and second layers of magnetic material. The edge closure layer eliminates magnetic edge closure domains and magnetic edge-curling walls in the yoke and poletip regions, or in a fluxguide of a magnetic recording head to substantially eliminate Barkhausen noise and wall network instabilities. Multiple layer laminates are also disclosed having a plurality of nonmagnetic layers each of which are sandwiched between layers of magnetic material and wherein the laminate includes edge closure layers that contact all the magnetic layers. Several methods are disclosed for fabricating the laminate. In one class of technique, the side edges are deposited together with a top layer in a single plating operation. In an another embodiment, the side edge closure layers are separately plated. Another embodiment provides for a layer of antiferromagnetic material deposited between the nonmagnetic layer and one of the magnetic layers to provide additional anisotropy.

Method of fabricating magnetic thin film structures with edge closure

The problem of characterizing metallic magnetic particles as suitable or unsuitable for use in a high density magnetic recording media is believed to have been solved by use of a figure of merit designated as 'W/H.sub.c ', and defined herein. It has been found that metallic magnetic particles which exhibit a W/H.sub.c of about 1.2 or less offer the most desirable magnetic recording characteristics for high density magnetic recording media. With this characterization technique available, it has been determined that most quantities of metallic magnetic cobalt-phosphorus particles produced by chemical reduction have W/H.sub.c 's greater than 1.2, and are unsuitable for use in high density magnetic recording media. Using W/H.sub.c, it has been possible to recognize those metallic particles which are suitable for use in high density recording media, and to engage in experimentation to determine what methods of manufacturing are required for the production of suitable high density recording particles. Surprisingly, following the recognition of the problem, it has been found that production of cobalt-phosphorus particles by controlled chemical reduction in a D.C. magnetic field of at least about 200 gauss consistently produces magnetic particles having W/H.sub.c of about 1.2 or less. In the absence of a D.C. magnetic field of at least about 200 gauss, cobalt-phosphorus particles having a W/H.sub.c as low as 1.2 are rarely produced.

Process for the production of magnetic materials

Growing community of inventors

Hollister, CA, United States of America

Thomas J Beaulieu