Hitachi, Ltd.

Masahide Suenaga

Noboru Shimizu

Hiroshi Yamamoto

Yukihisa Tsukada

Masahiro Kitada

Hiroshi Yamaguchi

Masao Mitani

Shinji Narishige

Kanji Kawakami

Masaki Ohura

Mitsuhiro Kudo

Tooru Takeura

Kousaku Chida

A thin-film permanent magnet which is made of a Co - Pt alloy containing 5-35 atomic-% of Pt. This thin-film permanent magnet can be readily produced by a sputtering method in which the ultimate pressure before the introduction of a sputtering gas is made 5.times.10.sup.-7 -1.times.10.sup.-4 Torr. Without any heat treatment, it has a coercivity of 2,000 Oe at the maximum and a remanence of about 8,000-about 18,000 G.

Thin-film permanent magnet and method of producing the same

A magnetoresistive head comprising a magnetoresistive element, to which a magnetic bias field is applied, is disposed opposite to a magnetic recording medium moving relative thereto, and the resistance value of the magnetoresistive element varying as a result of the relative movement of the magnetoresistive element and the magnetic recording medium is detected to reproduce information recorded on the magnetic recording medium. The magnetoresistive element of the magnetic head has an elongate shape extending along the easy axis of magnetization and has protrusions at its longitudinal ends. The protrusions have, for example, a semicircular or triangular contour. These protrusions are effective for suppressing formation of undesirable domain walls in the magnetoresistive element, so that the magnetic head can operate without substantial variation of its output voltage level and with reduced Barkhousen noise.

Magnetoresistive head

A magnetoelectric conversion element comprises a magnetoresistive effect material having a closed domain structure, a pair of contacts for supply of current flowing through the magnetoresistive effect material, and a bias electrode disposed between the contacts for biasing the direction of the current flow. The bias electrode is disposed so that the respective angles of intersection between the directions of current flow through different magnetic domains of the magnetoresistive effect material biased by the bias electrode and the directions of spontaneous magnetization biased by an external magnetic field are both increased or decreased.

Magnetoresistive sensor having a closed domain structure and electrode

A method of forming a multilayer thin film is disclosed in which a second thin conductive film is deposited on a first thin conductive film uninterruptedly after the first thin film has been deposited on a substrate, the first and second films thus formed are processed so as to form a predetermined pattern, the surface of the second thin film is cleaned by ion etching and a third thin conductive film is deposited on the whole surface of the substrate, and then the second and third thin films are processed so as to have a pattern different from the above-mentioned predetermined pattern. In the case where two thin conductive films different in material and pattern from each other are piled on a substrate, the above method can form a perfect interconnection between the two films and can make very small the contact resistance between the two films. Accordingly, the method is fit to form, for example, a barber pole type magnetoresistive element.

Method of forming a multilayer thin film

In forming a magnetic film pattern of permalloy by photoetching, the permalloy magnetic film formed on a substrate is etched in an etching solution containing ferric chloride, hydrochloric acid and phosphoric acid, thereby gradually reducing the thickness of the film pattern at the side edges in a tapered state. The permalloy magnetic film can be easily taper-etched without any deterioration of magnetic properties of permalloy magnetic film and substrate surface, but with a greatly improved yield of magnetic film head production and a greatly improved reliability.

Process for forming magnetic film pattern

Electrodes for a magnetoresistive sensor can be formed easily by a method wherein a double-layer structure of Mo and Al on a film of a magnetoresistive material such as permalloy is formed to have a predetermined pattern, firstly by exposing an Al layer to a chemical etching solution or subjecting the Al layer to the ion-milling treatment to give said Al layer said pattern and then subjecting a Mo layer to the plasma etching or reactive sputter etching treatment to give said Mo layer said pattern.

Formation of electrodes for magnetoresistive sensor

A method for producing a magnetic head, comprising the step of irradiating peripheral parts other than a track portion and/or a slider portion with a laser beam so as to selectively remove surface parts of the irradiated parts, thereby to form the track portion and/or the slider portion. According to this method, the track portion and/or the slider portion of the magnetic head can be worked at high working rate, at high precision and with low working deformation, with the result that the magnetic head of excellent reproduced output and crosstalk characteristics can be readily manufactured.

Growing community of inventors

Odawara, Japan

Masahide Suenaga