# US 5,708,544 A · Magnetic head

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- Number: US 5,708,544 A
- Document ID: US5708544A
- Status: Granted
- Kind: A
- Application number: 08/845,695
- Filed: 1997-04-25
- Granted: 1998-01-13
- Earliest claimed: 1994-08-22
- Assignees: Sony Corporation
- Inventors: Takashi Kawashima; Yutaka Okazaki
- Web page: https://patentgrep.com/patent/US5708544A

## CPC

- G11B 5/1878: {disposed immediately adjacent to the transducing gap, e.g. "Metal-In-Gap" structure}
- G11B 5/09: Digital recording
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

A magnetic head, in the form of a MIG head, having a magnetic metal film formed in the vicinity of the magnetic gap, is provided, in which the thickness of the magnetic metal film in a direction perpendicular to the magnetic gap is not less than 1.0 .mu.m and not more than 4.4 .mu.m and the gap length of the magnetic gap is 0.23 .mu.m to 0.32 .mu.m. The magnetic head is improved in recording characteristics in a specified short wavelength range and hence in the playback output so that it may be advantageously employed for a high digital recording format.

## Claims

### Claim 1

A metal-in-gap magnetic head having first and second magnetic core halves with a magnetic metal film formed on at least the region of a magnetic gap between said core halves,
wherein the improvement resides in that each of said first and second magnetic core halves has a planar surface confronting and parallel relative to one another across said magnetic gap, and a pair of inclined surfaces disposed on opposite sides of said planar surfaces rendering each of said core halves in a tapered shape;
a first magnetic metal film and a second magnetic metal film formed on said first and second magnetic core halves, respectively, to cover said planar surface and said inclined surfaces of each of said core halves;
said magnetic metal films having a thickness in a direction perpendicular to the magnetic gap of not less than 1.0 .mu.m and not more than 4.4 .mu.m, and said magnetic gap having a length of not less than 0.23 .mu.m and not more than 0.32 .mu.m; and
wherein said head is capable of recording signals having wavelengths in the range of 0.4 .mu.m to at least 0.7 .mu.m.

### Claim 2 (depends on 1)

The magnetic head according to claim 1, wherein at least one of said first and second magnetic metal films is composed of an alloy selected from the group consisting of:
Fe--Al--Si, Fe--Al, Fe--Si--Co, Fe--Ni, Fe--Al--Ge, Fe--Ga--Ge, Fe--Si--Ge, Fe--Co--Si--Al, Fe--Ga--Si.

### Claim 3 (depends on 1)

The magnetic head according to claim 1, wherein at least one of said first and second magnetic metal films is composed of an alloy composed of Fe, Ga, Co and substituting part of Fe with Si, and admixed with at least one element selected from Ti, Cr, Mn, Zr, Nb, Mo, Ta, W, Ru, Os, Rh, Ir, Re, Ni, Pd, Pt, Hf, and V.

### Claim 4 (depends on 1)

The magnetic head according to claim 1, wherein at least one of said first and second magnetic metal films is composed of an amorphous alloy composed of at least one element selected from the group consisting of Fe, Ni, Co; and one or more element selected from the elements P, C, B, and Si.

### Claim 5 (depends on 4)

The magnetic head according to claim 4, wherein said amorphous alloy further contains an element selected from the group consisting of Al, Ge, Be, Sn, In, Mo, W, Ti, Mn, Cr, Zr, Hf, and Nb.

### Claim 6 (depends on 5)

The magnetic head according to claim 5, wherein said amorphous alloys are further composed of transition elements selected from the group consisting of Co, Hf, Zr, and rare earth elements.

### Claim 7 (depends on 1)

The magnetic head according to claim 1, wherein said magnetic head comprises winding slots having coils wound there around, side winding slots formed as windows traversing said core halves at a mid portion of a substrate portion along a direction of depth of said magnetic gap.