JPH05282622A - Magnetic head - Google Patents

Abstract

PURPOSE:To prevent the occurrence of pinholes, etc., in a face in sliding contact with a tape. CONSTITUTION:A substance 6 having affinity for glass is incorporated into a layer of a gap material 5 which joins a pair of magnetic core halves 10 of an MIG type magnetic head so that the concn. of the substance 6 is made higher at the joining faces of the layer. When the magnetic core halves 10 are joined with molten glass, the substance 6 having affinity for the glass is oxidized and fuses in the glass. Improved wettability with the glass and enhanced adhesion are ensured, bubbles (pinholes) in the layer of the gap material 5 are expelled and pores in the layer are blocked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head.
More specifically, according to the present invention, a pair of magnetic core halves, at least one of which is composed of a substrate of an oxide magnetic material and a metal magnetic thin film, is provided with an oxide such as SiO ₂ or Si.
The present invention relates to a so-called metal-in-gap (MIG) type composite magnetic head in which a gap material made of a nitride such as N is interposed and abutted and joined with molten glass.

[0002]

2. Description of the Related Art In a MIG head, most of the core is composed of a substrate of an oxide magnetic material such as ferrite, and a thin film of a high magnetic flux density material such as sendust is used only in the pole piece portion. This MIG head is disclosed, for example, in JP-A 1-1007.
As shown in No. 14, a pair of magnetic core halves, at least one magnetic core half of which is composed of a substrate of an oxide magnetic material and a metal magnetic thin film, is butt fused glass with a gap material layer of SiO ₂ interposed. I am trying to join with.

In this magnetic head, the magnetic gap is such that the metal magnetic thin film of one magnetic core half body is abutted with a layer of SiO ₂ gap material interposed therebetween, and the metal magnetic thin film of the other magnetic core half body is opposed to this. It is formed between a thin film or an oxide magnetic material. Therefore, the metal magnetic thin film is formed by vacuum thin film formation such as sputtering along the surface of the track width formed on the gap facing surface of the oxide magnetic material (referred to as a butt joint surface parallel to the magnetic gap in this specification). Filmed by technology. The track width surface of the gap facing surface is formed in advance by providing the track facing groove of the oxide magnetic material that defines both ends of the magnetic gap and restricts the track width.

After the metal magnetic film is formed by sputtering, SiO ₂ is similarly applied on the metal magnetic film by sputtering to form the gap material layer. This magnetic core half body is joined by filling the above-mentioned track regulation groove with molten glass.

[0005]

However, this conventional magnetic head structure has a problem that bubbles are generated along the metal magnetic film in the glass beside the track.
When forming a spacer material such as SiO ₂ with a predetermined thickness by sputtering, since the sputtering is performed so as to face the gap facing surface, the SiO _{2 at the} gap facing surface portion is dense, but is separated from the gap facing surface. The SiO ₂ in the track control groove becomes a rough film surface full of holes. This appears as bubbles in SiO _{2 due} to the melting of molten glass during glass bonding, and finally causes pinholes or chipping (chips) on the tape sliding contact surface. The pinhole damages the medium such as a magnetic tape or clogs the dust, thus reducing the reliability of the head.

An object of the present invention is to provide a magnetic head which can prevent the occurrence of pinholes and the like.

[0007]

To achieve the above object, the present invention provides a pair of magnetic core halves, in which at least one magnetic core half is composed of a substrate of an oxide magnetic material and a metal magnetic thin film. In a magnetic head formed by abutting with a material layer interposed therebetween and bonding a pair of magnetic core halves with glass, the gap material layer to be bonded to the glass is provided with a glass affinity substance on the glass bonding side. The closer it is to the surface, the denser it is contained.

[0008]

Therefore, the film formed on the surface of the gap material and having a good affinity with the glass is oxidized when the magnetic core halves are joined with the molten glass, and becomes an oxide and melts into the molten glass. At this time, bubbles (pinholes) in the gap material layer are expelled to close the holes in the gap material.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is an exaggerated view of an embodiment of one of the magnetic core halves constituting the composite magnetic head of the present invention. This magnetic core half is composed of a substrate 1 of an oxide magnetic material made of, for example, ferrite, a metal magnetic thin film 3 of, for example, a Sendust alloy or the like formed on the gap facing surface 7, and some other extremely thin films. It In the magnetic core half body of this embodiment, the gap facing surface 7 of the magnetic gap portion of the substrate 1 has a predetermined track by a groove for restricting the gap facing surface 7 to the track width, for example, an arc-shaped track restriction groove 8. It is restricted in width.

On the substrate 1 of the oxide magnetic material, first SiO
A base film ₂ such as 2 is formed to prevent O ₂ from moving from the substrate 1 material to the film 3 side of sendust containing Al.

A metal magnetic film 3 of sendust alloy or the like is formed on the base film 2 in a desired thickness. The metal magnetic film 3 is formed in a shape that converges the magnetic flux toward the magnetic gap g from the track width surface of the gap facing surface 7 of the substrate 1 to the track restriction grooves 8 at both ends thereof, and concentrates the magnetic flux. It is provided so as to lead to g.

A Cr film 4 is formed on the metal magnetic film 3 to prevent the glass component of the gap material 5 from diffusing to the metal magnetic film 3 side.

SiO ₂ is formed on the Cr film 4 so as to obtain a predetermined gap length as the gap material 5.

A film 6 having a good affinity with glass is formed on the SiO ₂ gap material 5. This film 6 is made of a material having a good affinity with glass after oxidation such as Cr or Ti. The Cr film 6 is formed to have a film thickness of 50 Å to 5000 Å, preferably 100 Å to 300 Å by sputtering or the like. The film 6 having a good affinity with glass is composed of a single-phase film or a laminated film of a plurality of layers, and may be a mixed film in which a plurality of materials are mixed depending on the case.

FIG. 2 shows an embodiment of the MIG type composite magnetic head of this embodiment. In this composite magnetic head, a pair of magnetic core halves 10 and 11 as shown in FIG. 1 are butted, and molten glass 12 and 1 in which these are filled in track regulation grooves 8 and 8.
2 and the gap g is formed between the metal magnetic films 3 of the magnetic core halves 10 and 11. As shown in FIG. 1, the other films 4, 5 and 6 outside the metal magnetic films 3 and 3 facing the track restricting grooves 8 and 8 which were present at the time of the magnetic core half body before glass bonding, are glass bonded. After that, it melts into the bonding glasses 12, 12 to form a single glass layer. However, the films 6 and 6 having a good affinity with the glass in the magnetic gap g, the films of the gap materials 5 and 5 and the Cr films 4 and 4 for preventing diffusion remain as they are. The magnetic core halves 10 and 11 of this composite magnetic head
Although not shown, at least one of them has a winding groove for winding the coil.

The magnetic head having the above structure is manufactured as follows.

First, the ferrite substrates 1 and 1 to be the substrates of the magnetic core halves 10 and 11 are prepared, and the track opposing grooves 8 and 8 for regulating the track width and the necessary windings are provided on the gap facing surface 7 of the ferrite substrates 1 and 1. The line groove is cut by grinding.

Next, these ferrite substrates 1 and 1 are cleaned, and a Cr film 2 as a reaction preventing layer is formed on each gap facing surface 7 by using a thin film forming technique such as sputtering. In this case, the sputtering is usually performed so as to face the gap facing surface 7.

Then, a sendust alloy to be the metal magnetic thin film 3 is formed on the reaction preventing film 2 by, for example, sputtering. Usually, the metal magnetic film 3 is formed by facing the gap facing surface 7 or by sputtering while changing the direction as shown in JP-A 1-264614.

Then, a Cr film 4 for preventing diffusion of glass components to the sendust side is formed by sputtering similarly on the sendust film 3.

Thereafter, a SiO ₂ film 5 as a gap material is formed to a predetermined thickness by sputtering. At this time, since the sputtering is normally performed so as to directly face the gap facing surface 7, the SiO 2 on the gap facing surface 7 portion is formed.
_{While 2} is dense, SiO ₂ in the track regulating grooves 8 and 8 which are separated from the gap facing surface 7 becomes a rough film full of fine holes.

Then, a film 6 of a metal having a good affinity with glass, for example, Cr, is formed on the film of the gap material 5 of SiO ₂ by sputtering similarly. The film 6 is formed in the range of 50 angstroms to 5000 angstroms, for example.

The pair of magnetic core halves 10 and 11 thus formed are abutted against each other and joined together with molten glass 12 and 12 so as to obtain a magnetic gap g having a predetermined track width. At this time, the molten glass 12 is filled in the track restricting grooves 8, 8 of the magnetic core halves 10, 11 that are butted. When the molten glass 12 is filled, the Cr films 6 and 6 formed on the surfaces of the SiO ₂ gap material films 5 and 5 are oxidized to become CrO ₂ . Since this chromium oxide has a good affinity and wettability with the glass, it is melted into the molten glass 12, 12 so that the spacer material S in the track regulating groove 8, 8
Block the holes while pushing out the pinholes of iO _2, 5, 5.
Therefore, in the track regulating grooves 8 and 8 outside the metal magnetic films 3 and 3 after glass bonding, the Cr films 6 and 6 of the outermost layer are also
The gap material films 5 and 5 are also diffusion preventing Cr films 4 and 4.
Also melts into the bonding glasses 12, 12 to form a single glass layer. However, the Cr films 6 and 6 in the magnetic gap g portion, the gap material films 5 and 5 and the diffusion preventing C
The r films 4 and 4 remain as they are between the metal magnetic films 3 and 3.

Thereafter, the magnetic core is subjected to necessary grinding, lapping and slicing, and is cut out into a large number of magnetic head chips.

The above-mentioned embodiment is one example of the preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, in this embodiment both magnetic core halves 10, 1
Although the composite magnetic head in which the metal magnetic thin film 3 is formed on each of 1 is described above, the present invention is not limited to this. For example, the composite magnetic head in which the metal magnetic thin film is formed only on one magnetic core half body. It goes without saying that it can also be applied to. In this case, a magnetic metal thin film of one of the magnetic core halves that is butted with a gap material layer interposed,
A gap g is formed between the oxide magnetic material of the other half of the magnetic core that faces this.

Further, the layer of gap material 5 is not limited to SiO _2, an oxide or nitride such as SiN, such as SiO ₂ or the like, may be further low-melting glass.

[0028]

As is apparent from the above description, in the magnetic head of the present invention bonded with glass, the glass affinity substance is close to the glass bonding side surface in the gap layer where the glass is bonded. Since it is contained so densely, when the magnetic core halves are joined with molten glass, the film that has a good affinity with glass is oxidized and becomes an oxide that melts into the molten glass and becomes wettable with the glass. Since it raises the adhesiveness by raising it, it expels air bubbles (pinholes) in the gap material layer and closes the holes in the gap material layer. Therefore, even when used as a head, pinholes and chipping (chips) do not occur on the tape sliding contact surface.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an exaggerated film portion of an example of a magnetic core half body constituting a magnetic head of the present invention.

FIG. 2 is a plan view of a magnetic head formed by using the magnetic core half body of FIG. 1 as seen from a tape sliding contact surface.

[Explanation of symbols]

 1 Substrate of oxide magnetic material 3 Film of metal magnetic material 5 Film of gap material 6 Film of glass affinity material

Claims (1)

[Claims] 1. A pair of magnetic core halves, at least one magnetic core half of which is composed of a substrate of an oxide magnetic material and a metal magnetic thin film, butted together with a gap material layer interposed therebetween. In a magnetic head formed by joining a body with glass, the layer of the gap material where the body is joined to the glass contains a glass-affinity substance with a higher density as it is closer to the glass-joining side surface. ..