JPH0696413A - Magnetic core and floating type magnetic head - Google Patents

Abstract

PURPOSE:To execute recording and degaussing by constituting the floating type magnetic head in such a manner that a pseudo gap is not generated and that the distribution width of magnetic lines of force recordable in a gap part does not increase even if the input current to a magnetic core is increased. CONSTITUTION:Inner magnetic films 6 are deposited on the respective opposite surfaces of a pair of nonmagnetic core pieces 5 and both the core pieces 5 are joined between both the inner magnetic films in such a manner to have a gap part 4. Outer magnetic films 8 are provided exclusive of the side parts near the gap parts on the flanks orthogonal with the joint surfaces of the two core pieces 5. A winding window 7 is formed in the part of the outer magnetic film 8 nearer the gap part 4 and magnetic circuits are formed from the gap part 4 successively to the one inner magnetic film 6, the outer magnetic film 8, the other inner magnetic film 6 and the gap part 4. The magnetic core 3 constituted in such a manner is fixed within the slit of the slider 1, by which the floating type magnetic head is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for a magnetic tape device and a magnetic disk device, and more particularly to a magnetic head for recording / reproducing information on / from a magnetic disk and a magnetic core attached to the magnetic head. Instead, the reproduction output characteristics are improved.

[0002]

2. Description of the Related Art As a floating type magnetic head, a magnetic core is integrally formed with a slider, and a slider part itself constitutes a part of a main magnetic path. A composite type fixed with wood is used. In the monolithic type, since the slider itself constitutes a part of the main magnetic path, a high output can be obtained in reproduction. The composite type is suitable for high density because the track width of the magnetic core can be reduced.

As a magnetic core used in a composite type floating magnetic head having a magnetic core fixed to a slit of a slider, as shown in FIG. 4A, a magnetic film 22 is formed on a surface opposite to a pair of magnetic core pieces 21. Is adhered and bonded with a glass material 24 so as to have a gap portion 23 between both magnetic films. Further, as shown in FIG. 4B, a pair of core pieces 27 in which a plurality of magnetic films 26 are laminated between two non-magnetic substrates 25 are joined by a glass material 29 so as to have a gap portion 28 between them. There is something.

[0004]

In the magnetic core shown in FIG. 4A, most of the lines of magnetic force pass through the magnetic film adhered to the core piece near the magnetic gap, so that the input current to the magnetic core becomes large. However, the width of distribution of recordable lines of magnetic force in the gap portion does not increase so much, and recording demagnetization rarely occurs during recording on the disc. However, when the input current becomes large, not only the magnetic film but also the magnetic core piece outside the magnetic film becomes a magnetic circuit, and the magnetic flux leaks from the magnetic core to the gap portion. Therefore, there is a problem that a pseudo gap (SGP) shown in FIG. 5 is generated in the reproducing process. In addition, in the magnetic core of FIG. 4A, a C-type core and an I-type core are used as a pair of cores.
A magnetic film is deposited on each facing surface of the mold core, but it is difficult to form the magnetic film with a uniform thickness on the entire facing surface of each core, particularly on the winding window. Could not be formed.

In the magnetic core shown in FIG. 4B, since only one kind of magnetic film exists on both sides of the gap portion 28, the pseudo gap does not occur as described above. However, when the input current to the magnetic core is increased, the lines of magnetic force pass through the magnetic film that composes both core pieces and exists widely on both sides of the gap, so the distribution width of the recordable magnetic lines of force generated from the gap is large. Becomes larger, the recording demagnetization occurs, and the reproduction output becomes smaller. The reproduction output of the magnetic head using the magnetic core shown in FIG. 4B was measured, and the result was as shown in FIG. 6A. That is, when the input current to the magnetic core is small to some extent, the reproduction output is large, but when the input current is large, the reproduction output tends to decrease. This means that the signal width written in FIG. 6 (a) becomes larger as the input current becomes larger, and the previously magnetically recorded portion is re-magnetized later by the wider signal, resulting in recording demagnetization. It becomes. Therefore, the present invention eliminates the recording demagnetization by preventing a pseudo gap from being generated in the magnetic head, and by preventing the distribution width of recordable magnetic force lines in the gap portion from increasing even if the input current to the magnetic core is increased. The purpose is to

[0006]

The present invention achieves the above object in a magnetic core used in a magnetic head for magnetically recording / reproducing data to / from a magnetic disk. The structure of the magnetic core is such that an inner magnetic film is adhered to each facing surface of a pair of non-magnetic core pieces, and both core pieces are joined so as to have a gap portion between both inner magnetic films. An outer magnetic film is provided on a side surface orthogonal to the bonding surface except for a side portion close to the gap portion, and a portion of the outer magnetic film near the gap portion is formed as a cutout portion. A magnetic circuit is formed on the outer magnetic film, the other inner magnetic film, and the gap. In order to narrow the track width, the magnetic core may have a narrow notch at the edge of the pair of joined core pieces on the side of the gap. If the magnetic core is fixed in a slit provided in the same direction as the air bearing surface of the slider, it can be manufactured as a floating magnetic head.

[0007]

In the above magnetic core, a magnetic circuit is formed in order from the gap portion to one of the inner magnetic film, the outer magnetic film, the other inner magnetic film and the gap portion, and the magnetic materials on both sides of the gap portion are non-magnetic. Only the magnetic film adhered to the facing surface of the core piece does not generate magnetic lines of force other than the magnetic film, so that no pseudo gap is generated. Even when the input current to the magnetic core becomes large, the magnetic force lines pass from the magnetic film adhered to one core piece to the magnetic film adhered to the other core piece beyond the gap portion, so The distribution width does not become large. Therefore, when the above magnetic core is used, recording demagnetization does not occur and the reproduction output is not reduced. Then, the reproduction output and the signal width in the magnetic head using the above magnetic core are as shown in FIG. 6B, and the signal width is almost constant even if the input current becomes large, and the reproduction output does not decrease. I understand.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic core of the present invention will be described with reference to FIGS. 1 and 2, and an embodiment of a floating magnetic head will be described with reference to FIG. In the magnetic core 3 incorporated in the magnetic head, the inner magnetic films 6 are attached to the respective facing surfaces of a pair of core pieces 5 made of a non-magnetic material such as ceramic, and a gap portion 4 is provided between the inner magnetic films 6. Thus, the pair of core pieces 5 are joined by the glass material 9. The side surface of each inner magnetic film 6 is shown on the side surface orthogonal to the joining surface of the pair of core pieces 5 joined in this way, and the outer magnetic film is provided on one side surface showing the inner magnetic film 6. The membrane 8 is applied. Outer magnetic film 8
Is attached except the side portion near the gap portion 4, the outer magnetic film is joined to the two inner magnetic films 6, and the outer magnetic film 8 is formed in the winding window 7 in the portion close to the gap portion 4. Then, a magnetic circuit in which magnetism acts on the inner magnetic film 6, the outer magnetic film 8, the other inner magnetic film 6, and the gap portion 4 in this order from the gap portion 4 is formed.

A glass material 9a is adhered to a portion of the outer magnetic film 8 near the gap of the winding window 7, and the magnetic core 3 formed as described above has a central portion of a pair of core pieces 5 joined together. The coil is wound through a through hole corresponding to the position of the winding window 7. In the above description, the outer magnetic film 8 is attached by removing the side portion close to the gap portion 4. However, for convenience of manufacturing, the outer magnetic film 8 is attached to the entire side surfaces of the pair of core pieces 5 and then the outer magnetic film 8 is attached to the outer side. You may make it cut out the side part near the gap part of the magnetic film 8. Further, in order to reduce the track width T _{w of the} portion of the magnetic core 3 close to the gap portion 4, the edge portion of the magnetic core 3 on the side of the gap portion 4 is notched as shown in FIG.

The magnetic core 3 formed as described above is shown in FIG.
As shown in (1), the composite magnetic head is produced by inserting it into a slit 2a perpendicular to and parallel to the air bearing surface 2 of the slider 1 and fixing it with a glass material. In this case, the gap portion 4 of the magnetic core 3 is arranged so as to face the air bearing surface 2. In the flying magnetic head thus produced, two air bearing surfaces 2 are provided in parallel with each other on the surface of the slider 1 facing the magnetic disk with a gap. The slider 1 floats above the magnetic disk at a minute interval by the air flow acting on the air bearing surface 2 of the slider 1 when the magnetic disk rotates. Further, magnetic recording and reproduction are performed between the gap portion 4 of the magnetic core 3 and the magnetic disk.

[0011]

According to the magnetic core or magnetic head of the present invention, the magnetic core has a non-magnetic core piece coated with a magnetic film, and the side surface orthogonal to the joining surface of the joined core pieces is close to the gap. Since the outer magnetic film is deposited except for the part and a magnetic circuit is formed in order from the gap part to the one inner magnetic film, the outer magnetic film, the other inner magnetic film, and the gap part, a pseudo gap may occur. Even if the input current to the magnetic core is large, the width of distribution of recordable magnetic lines of force in the gap portion is small, so that recording demagnetization does not occur and the reproduction output becomes large.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic core of the present invention.

FIG. 2 is a perspective view of another embodiment of the magnetic core.

FIG. 3 is a perspective view of a floating magnetic head to which a magnetic core is attached.

FIG. 4 is an explanatory diagram showing two types of conventional magnetic cores.

FIG. 5 is an explanatory diagram showing an output waveform of a magnetic head.

6A and 6B are relationship diagrams showing the reproduction output and the waveform width of the output signal with respect to the input current in the conventional example and the magnetic head of the present invention, where FIG. 6A shows the conventional example and FIG. 6B shows the case of the present invention.

[Explanation of symbols]

 1 slider 3 magnetic core 5 core piece 6 inner magnetic film 8 outer magnetic film

Claims (3)

[Claims] 1. A magnetic core incorporated in a floating magnetic head for magnetically recording / reproducing data to / from a magnetic disk, wherein inner magnetic films are deposited on respective facing surfaces of a pair of non-magnetic core pieces, Both core pieces are joined so as to have a gap portion between both inner magnetic films, an outer magnetic film is provided on a side surface orthogonal to the joining surface of both core pieces except for a side portion close to the gap portion, and an outer magnetic film. A winding window is formed in a portion close to the gap portion, and a magnetic circuit is sequentially formed from the gap portion to one inner magnetic film, outer magnetic film, the other inner magnetic film, and the gap portion. Magnetic core to do. 2. The magnetic core according to claim 1, wherein the pair of core pieces joined to each other are notched so that the edges on the gap side are narrowed to form a narrow track width. . 3. A flying type magnetic head, wherein the magnetic core according to claim 1 or 2 is fixed in a slit provided in the same direction as the air bearing surface of the slider.