Sony Corporation

Akira Urai

Takashi Tamura

Toru Matsunaga

Atsushi Suzuki

Hideaki Ojima

Fusashige Tokutake

Yukari Nihei

Masatoshi Hayakawa

Junichi Honda

Yoshito Ikeda

Tatsuo Kumura

Tomio Kobayashi

Heikichi Sato

Toshiyuki Okada

Akira Murakami

Mitsuaki Yokomizo

Fumio Kurosawa

Kazuhiro Yagihashi

Astushi Suzuki

A magnetic head having excellent abrasion characteristics and a high playback output. The magnetic head is made up of a pair of magnetic core halves each having a single crystal ferrite at a portion thereof, said magnetic core halves being abutted and joined to each other, with a magnetic gap being formed between abutment surfaces of these magnetic core halves. The single crystal ferrite has its medium sliding surface, slidingly contacted with a magnetic recording medium, as a (411) plane, and also has the abutment surface as a (122) plane.

Magnetic head with (411) plane single crystal ferrite medium facing surface and (122) plane gap surface

A magnetic head having a pair of magnetic core halves integrally bonded to each other, each magnetic core half being formed by a single-crystal ferrite piece and a polycrystal ferrite piece bonded together to constitute a junction ferrite, with a magnetic gap being defined between abutting surfaces of the magnetic core halves. The single-crystal ferrite pieces are arranged towards the abutting surfaces of the magnetic core halves and the polycrystal ferrite pieces are arranged on the opposite side of the abutting surfaces with respect to the single-crystal ferrite pieces. Preferably, the surface of the single-crystal ferrite piece having sliding contact with the magnetic recording medium, the gap surface of the single-crystal ferrite piece and the surface of the single-crystal ferrite piece corresponding to the lateral surface of the magnetic head are the (211) plane, (111) plane and the (110) plane, respectively. The directions of the &lt;100&gt;crystal axes within the plane (100) are symmetrical to each other on both sides of the magnetic gap. The magnetic head is low in sliding noise and superior in electro-magnetic conversion characteristics. In addition, the magnetic recording medium is superior in abrasion characteristics since the partial advancing abrasion is prohibited from occurring on its surface configured to have sliding contact with the magnetic recording medium.

Magnetic head

This invention provides a magnetic head suitably used for replay because of its giving a high output with a low noise. A magnetic head suitable for replay is provided which is made of a pair of magnetic cores 1 and 2 facing each other with a magnetic gap g.sub.1, in between and composed of composite ferrites consisting of monocrystal ferrites 9 and 11, and polycrystal ferrites 10 and 12 each containing 52-54 mol % of Fe.sub.2 O.sub.3, 24-26 mol % of ZnO and 20-24 mol % of MnO. Further, the monocrystal ferrites 9 and 11 are allowed to take the same orientation with a so-called VHS direction. Furthermore, the fusion glass 3 to bond the magnetic cores 1 and 2 is allowed to have a linear thermal expansion coefficient less by 20.times.l0.sup.-7 -26.times.10.sup.-7 than that of the composite ferrites composing the magnetic cores 1 and 2, at temperatures from 100.degree. to 350.degree. C.

A magnetic head comprising a pair of magnetic core halves each having a magnetic core film sandwiched between a pair of non-magnetic substrates, said magnetic core halves being abutted to each other with the end faces of the magnetic core films facing each other, with a magnetic gap being defined in an interface of abutment of said magnetic core films, wherein the magnetic core film is of a laminated magnetic film structure comprising a plurality of laminated magnetic film units laminated with insulating films in-between. Each laminated magnetic film unit in turn comprises a plurality of magnetic films with non-magnetic films in-between, with the magnetic films being magnetostatically connected to one another at film ends. By employing the laminated magnetic film unit for the magnetic core film, it becomes possible to markedly increase the magnetic permeability in a direction normal to the gap depth when anisotropy is applied in the gap depth direction. With the above magnetic head, a plurality of the magnetic film units are laminated with insulating films in-between for suppressing eddy current losses in the high frequency region. As a result, excellent electro-magnetic transducing characteristics may be obtained in the high frequency range.

A non-magnetic material for a magnetic head and a magnetic head produced with the use of such material. For improving the head efficiency and resistance against partial abrasion, the guard piece 11 is mainly composed of CaO, TiO.sub.2 and NiO, with the molar mixing ratio CaO/TiO.sub.2 being 30/70 to 50/50 and the NiO content being 5 to 30 mol %. The head efficiency may be improved, while the partial abrasion may be decreased and the service life of magnetic head may be improved sufficiently.

Magnetic head having Cao-TiO.sub.2 -NiO ceramic with specified CaO/TiO.sub.

Each of a pair of magnetic core halves includes a substrate and a thin magnetic metal film formed on the substrate. The substrate is notched with a winding groove. The pair of the magnetic core halves are integrally bonded to each other so that a gap filling film is formed between the facing surfaces of the thin magnetic metal films. The zero depth position of the magnetic gap which is determined by the length of the facing thin magnetic metal films is offset to a magnetic recording medium sliding surface of the magnetic head from the notching start position of the winding groove on the side of the magnetic gap. Hence, the shape of the thin magnetic metal film exposed on the magnetic recording medium sliding surface is maintained constant from the initial position to the depth zero position.

Magnetic head having a notched magnetic core portion with a zero depth

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Miyagi, Japan

Akira Urai