Denki Kagaku Kogyo Kabushiki Kaisha

Sumitomo Special Metals Co., Ltd.

Noboru Iwato

Hideki Mine

Wada Toshiaki

Kozi Kishida

Yuji Ozeki

Masami Yamashita

A thin-film perpendicular magnetic recording and reproducing head including a magnetic member defining a return path and having a narrow groove formed in one of its principal surfaces in parallel to a sliding surface adapted to face a magnetic recording medium, a non-magnetic material filling the groove, and a multilayer film assembly formed above the groove and consisting at least of a thin-film conductor coil, an interlayer insulating film, a thick main pole film, a main pole film and a protective film formed one upon another. The magnetic member is connected to the main pole film through a via hole portion, and is exposed on the sliding surface in the vicinity of the main pole film so as to face the recording medium. A thin magnetic film serving as a magnetic shield covers the protective film and the sidewall surface of the head and is joined to the sidewall surface of the magnetic member.

Thin-film perpendicular magnetic recording and reproducing head having

A composite plastics sheet made of a polystyrene base resin or an ABS base resin is provided. The composite plastics sheet has a conductive covering layer laminated by co-extrusion on the face of the substrate sheet. The material for the conductive covering layer is made of a polystyrene base resin or an ABS base resin and mixed with a conductive carbon black material, such as furnace black or channel black, in an amount such that the flow index at the extrusion step thereof at 200.degree. C. and under a loading of 5 kg is not lower than 0.1 g/10 min and such that the surface specific resistance of the resultant mixture is not more than 10.sup.10 ohms.

Composite plastics sheet having conductive surface

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Zama, Japan

Noboru Iwato