JPH087216A - Mig-type magnetic head and its production - Google Patents

Abstract

PURPOSE:To produce a high-quality MIG magnetic head prevented in noise due to a pseudogap. CONSTITUTION:This magnetic head has a core chip 1 produced by joining a pair of ferrite core half bodies 2 with glass 3. Each core half body has a metal magnetic film 4 having high saturation magnetic flux density such as 'Sendust' on the top and a magnetic G is formed between the metal magnetic films 4. The top face of the core chip 1 is polished so as to make the magnetic gap G and the metal magnetic films 4 extending on both sides of the gap G constitute a medium sliding face (m). The pseudogap (g') formed on the interface between the opposite edge of the metal magnetic film 4 to the magnetic gap G and the core half body 2 is present at a distance far enough from the magnetic gap G almost in the center of the sliding face (m). Thereby, production of noise such as sliding noise due to the pseudogap g' during recording and reproducing with the magnetic gap G is prevented. Thus, a high-quality MIG magnetic head for VTR or HDD is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a MIG [metal in gap] type magnetic head in which a metal magnetic film having a high saturation magnetic flux density is formed between a ferromagnetic core and a magnetic gap formed of a non-magnetic material. The manufacturing method is related.

[0002]

2. Description of the Related Art A MIG type magnetic head for recording and reproducing information at a high recording density on a magnetic recording medium such as a magnetic tape of a VTR or a hard disk of an HDD is provided between a ferromagnetic core and a non-magnetic magnetic gap. A metal magnetic film with a high saturation magnetic flux density such as sendust is formed on. The core chip of this MIG type magnetic head is generally one in which a pair of core halves of a ferromagnetic material such as ferrite are glass-bonded, and a conventional example thereof will be described with reference to FIGS. 10 and 11.

FIG. 1 shows a VTR core chip 11,
In this, a pair of ferrite core halves 12 are joined and integrated with glass 13. Each of the core halves 12 has a winding groove 14 and a track sizing groove 15 that also serves as a glass filling groove on the joint surface side, and Ni is formed on the surface where the track sizing groove 15 is present.
A metal magnetic film 16 which is a thin film of an —Fe alloy (permalloy) or the like is formed. The pair of core halves 12 are joined and integrated to form a magnetic gap G between the metal magnetic films 16.

In the VTR core chip 11, the top surface having the magnetic gap G is substantially spherically polished with the magnetic gap G as the apex position, and a medium sliding contact surface m'for sliding contact with a magnetic tape of a magnetic recording medium (not shown). It is said that A closed magnetic circuit is formed by the pair of core halves 12, the metal magnetic film 16, and the magnetic gap G, and the magnetic gap G is formed with a predetermined track width.
The information is recorded / reproduced on / from the magnetic tape which is in sliding contact with the magnetic gap G in the orthogonal direction. The metal magnetic film 16 increases the leakage magnetic flux density in the magnetic gap G to increase the information recording / reproducing density in the magnetic recording medium.

[0005]

When information is recorded / reproduced by sliding a magnetic tape on the magnetic gap G formed on the medium sliding contact surface m ′ of the core chip 11, the metal magnetism on both sides of the magnetic gap G is used. A slight leakage magnetic flux may be generated at the interface between the film 16 and the core half 12 to cause sliding noise, noise such as wiggle, or the like during recording / reproduction of the magnetic gap G. The interface between the metal magnetic film 16 and the core half body 12 that generates such noise is called a pseudo gap g ′. The higher the parallelism between the pseudo gap g ′ and the magnetic gap G, the more easily noise is generated and the MIG type. It is difficult to improve the quality of the magnetic head.

It is an object of the present invention to eliminate the influence of the pseudo gap from the recording / reproducing operation of information by the magnetic gap formed between the metal magnetic films, and to improve the quality easily.
It is to provide an IG type magnetic head.

[0007]

The magnetic head of the present invention comprises:
It has a core chip in which a pair of ferromagnetic core halves each having a metal magnetic film with a high saturation magnetic flux density at the top are joined together by forming a magnetic gap between the metal magnetic films of the two core halves. A medium sliding contact surface that approaches or contacts an external magnetic recording medium of the core chip is formed of the magnetic gap and the surface of the metal magnetic film of each core half extending on both sides of the magnetic gap.

The method of manufacturing the magnetic head of the present invention is
A process of forming a metal magnetic film with a high saturation magnetic flux density on one surface of a rectangular base material of a ferromagnetic body, and a plurality of track width-grooving grooves parallel to one surface orthogonal to the surface of the metal magnetic film of the core base material. A step of forming a core block by glass-bonding one surface of the pair of core base materials having the track width-developing groove with a magnetic gap formed between the metal magnetic films of the core base materials,
The method is characterized by including a step of slicing the core block in a direction parallel to the track width forming groove to obtain a plurality of core chips.

Further, according to the method of manufacturing a magnetic head of the present invention, a step of forming a plurality of tracks for track width increasing parallel to one surface of a core base material of a rectangular ferromagnetic material, and a step for forming track width increasing grooves of the core base material A step of forming a metal magnetic film having a high saturation magnetic flux density on the existing surface, a step of slicing the core base material in the direction orthogonal to the track width-developing groove to obtain a core bar, and a direction orthogonal to the track width-developing groove of the pair of core bars. The steps of glass-bonding one surface to form a magnetic gap between the metal magnetic films of the core bars to obtain a core block, and the step of slicing the core block in the direction parallel to the track width-grooving groove to obtain a plurality of core chips are performed. It is characterized by including.

[0010]

[Function] In a core chip in which a pair of ferromagnetic core halves each having a metal magnetic film having a high saturation magnetic flux density on the top thereof are joined and integrated, a magnetic gap between the metal magnetic films of each core half and both sides thereof are formed. A medium sliding contact surface is formed by the extending metal magnetic film, and a pseudo gap, which is an interface between the core half and the metal magnetic film, is located at a position sufficiently distant from the magnetic gap on the medium sliding contact surface. The pseudo gap has a higher influence on the recording / reproducing operation of the magnetic gap as it is parallel to the magnetic gap. However, in the magnetic head of the present invention, since the pseudo gap does not exist on the sliding contact surface, it has an influence on the recording / reproducing operation. Almost nothing.

[0011]

EXAMPLES Various examples will be described below with reference to FIGS. 1 to 9. The same or corresponding parts are denoted by the same reference symbols throughout the drawings.

1 and 2 show a core chip 1 in the MIG type magnetic head of the first embodiment. The core chip 1 is, for example, for VTR, and is made of ferrite (for example, Ni-
A pair of core halves 2 made of a ferromagnetic material (preferably Zn-ferrite or the like) is joined with glass 3 to form a magnetic gap G at the joined portion. The pair of core halves 2 each have sendust, permalloy, FeTaN alloy, Fe on top.
It has a metal magnetic film 4 of high saturation magnetic flux density such as TaCuN alloy, and a magnetic gap G is formed between the end faces of the pair of metal magnetic films 4. The top surface on which the magnetic gap G of the core chip 1 and the metal magnetic film 4 are present is substantially spherically polished, and the polished metal magnetic film 4 and the magnetic gap G serve as an external magnetic recording medium (in this case, a magnetic tape). A medium sliding contact surface m that makes sliding contact is formed.

Further, the pair of core halves 2 have a track width extending groove 5 and a winding groove 6 for determining the length (track width) of the magnetic gap G on the end faces of the respective joining sides. The track width-developing groove 5 also serves as a glass filling groove for joining the cores, and the groove 5 is filled with the glass 3 to form a pair of core halves 2
Are joined and integrated.

The metal magnetic film 4 of the pair of core halves 2 is a sputtered film or the like and extends in the medium sliding direction of the core chip 1.
The ends on the side opposite to the magnetic gap G are located on both ends of the medium sliding contact surface m. In the VTR core chip 1,
Due to the fact that the medium sliding surface m is polished to a substantially spherical surface, the ends of the metal magnetic film 4 opposite to the magnetic gap G appear in an arc shape at both ends of the medium sliding surface m. Therefore, the metal magnetic film 4 of each core half 2 is
The pseudo gap g ′ formed at the interface between the end opposite to the magnetic gap G and the core half body 2 is formed non-parallel to the magnetic gap G at both ends of the medium sliding contact surface m.

By thus polishing the medium sliding contact surface m into a substantially spherical surface, the pseudo gap g'becomes arcuate and is not parallel to the magnetic gap G. As a result, the recording / reproducing operation of the magnetic gap G by the pseudo gap g'is performed. The adverse effect on is eliminated.

An example of a method of manufacturing the core chip 1 of FIG. 1 according to the present invention will be described with reference to FIG.

As shown in FIG. 3 (a), the metallic magnetic film 4 is formed on the top surface of the rectangular ferrite core base material 7 by sputtering.
And glass 3 are laminated. This core base material 2 and 1 other
One ferrite core 8 is prepared, the two core base materials 7 and the ferrite core 8 are polymerized, and the glass 3 of each core base material 7 is utilized to glass-bond the three. Next, as shown in FIG. 3B, a plurality of parallel track width-developing grooves 5 are formed in the longitudinal direction on one side surface of each core base material 7 that is joined and integrated and is orthogonal to the metal magnetic film 4. The winding groove 6 is formed in the lateral direction. Next, as shown in FIG. 3 (c), a pair of core base materials 7 on which the groove processing has been completed are brought into abutment with their groove forming surfaces, and a glass rod 3 ′ is inserted into the winding groove 6 to form a glass rod. The rod 3'is heated and melted, and the pair of core base materials 7 are glass-bonded to each other to obtain the core block 9. At this time, a magnetic gap is formed in the core base material joint portion of the core block 9.

Next, the core block 9 shown in FIG. 3 (c) is sliced in the horizontal direction to obtain the core block 9 shown in FIG. 3 (d). The core block 9 is sliced in the direction parallel to the track width-developing groove 5, that is, the broken line portion in FIG. 3D is sliced to obtain the core chip 1 shown in FIG. The top surface of the core chip 1 is a flat surface formed by the metal magnetic film 4. Then, the top surface of the core chip 1 is spherically polished to obtain the core chip 1 of FIG.

The manufacturing of the core chip 1 of FIG. 1 is not limited to the above example, but when it is manufactured by the core base material forming step, the core base material groove processing step, the core block forming step and the core block slicing step as shown in FIG. The core chip 1 with stable quality can be manufactured with high mass productivity.

4 and 5 show the core chip 1 in the MIG type magnetic head of the second embodiment. The core chip 1 is mainly used for HDDs, and a pair of core halves 2 made of a ferromagnetic material such as ferrite are joined by glass 3. Each of the pair of core halves 2 has a metal magnetic film 4 having a high saturation magnetic flux density such as sendust on the top thereof, and a magnetic gap G is formed between the end faces of the pair of metal magnetic films 4. The magnetic gap G of the core chip 1 and the front surface and the side surface of the top where the metal magnetic film 4 is present are ground in a taper manner, and the top surface of the metal magnetic film 4 and the magnetic gap G is ground to an external magnetic recording medium (in this case, A flat medium sliding contact surface m that approaches or contacts the hard disk.

In the HDD core chip 1 of FIG.
A pseudo gap g ′ is formed in a part of the tapered surface n formed from both ends of the medium sliding contact surface m to the side surface of each core half body 2. Since the pseudo gap g ′ is located away from the medium sliding surface m, the pseudo gap g ′ does not adversely affect the recording / reproducing operation of the magnetic gap G.

FIG. 6 shows a core chip 1 for an HDD in the MIG type magnetic head of the third embodiment. This core chip 1 has basically the same structure as the core chip 1 of FIG. 4, and only the magnetic gap G of the core chip 1 and the front surface of the top where the metal magnetic film 4 is present are ground in a taper shape, so that the metal magnetic film 4 and the magnetic A flat medium sliding contact surface m is formed on the top surface of the gap G.

In the case of the core chip 1 of FIG. 6, a pseudo gap g'is formed at the interface between the side surface of the core half body 2 and the end surface of the metal magnetic film 4. Since the pseudo gap g ′ is also located away from the medium sliding surface m, the pseudo gap g ′ does not adversely affect the recording / reproducing operation of the magnetic gap G.

The core chip 1 of FIG. 4 and the core chip 1 of FIG.
Although it is possible to carry out the manufacturing process in the manufacturing process shown in FIG. 3, it is also possible to manufacture it by the manufacturing method of the present invention shown in FIGS. 8 and 9 described below.

That is, as shown in FIG. 8A, a plurality of parallel track-shaped grooves 5 having a V-shaped cross section are formed on the top surface of the rectangular core base material 7 of ferrite. This groove 5 also serves as a glass filling groove. After the groove processing, the metal magnetic film 4 is formed on the surface of the core base material 7 where the groove 5 is present by sputtering.
Next, as shown in FIG. 8B, the glass 3 is molded on the metal magnetic film 4 of the core base material 7 and polished to a predetermined thickness. After that, the core base material 7 is sliced in a direction orthogonal to the track width-developing groove 5, that is, the broken line portion of FIG. 8B is sliced to manufacture the core bar 10 as shown in FIG. 8C.

A winding groove 6 is formed laterally on one side surface of the core bar 10 which is orthogonal to the surface on which the glass 3 is present, and the pair of core bars 10 are butted against each other on the surface where the winding groove 6 is present. Glass bonding is performed to obtain a core block 9 shown in FIG. The core block 9 is sliced in a direction parallel to the track width-developing groove 5 to manufacture a plurality of core chips 1 with good mass productivity. The slicing points of the core block 9 are the troughs of the V-shaped track width increasing grooves 5 and the points between the adjacent grooves 5. Next, the track width extending groove 5 of the core chip 1
The surface opposite to that is ground to determine the track width of the magnetic gap G, and the top of the core chip 1 is ground into a tapered shape to manufacture the core chip shown in FIGS.

FIG. 7 shows a core chip 1 for an HDD in the MIG type magnetic head of the fourth embodiment. In this core chip 1, an I-shaped core half body 2'and a horizontal H-shaped core half body 2 "having a winding groove 6 on both side surfaces are joined by a glass 3. A pair of core half bodies 2 '. The top portion of 2 "has a mountain-shaped vertical cross section, and the metal magnetic film 4 is formed on this top surface, and a magnetic gap G is formed between the metal magnetic films 4 of the pair of core halves 2'and 2". , A pair of core halves 2 ′, 2 ″, the metal magnetic film 4 and the glass 3 have a polished top surface and a flat medium sliding contact surface m.
Is formed.

In the manufacture of the core chip 1 of FIG. 7, basically, the interval between the track width-growing grooves 5 formed in the core base material 7 of FIG. 8 is set to the track width, and the core block 9 of FIG. 9 is tracked. It may be manufactured by slicing at the valley portion of the tenter groove 5. In the core chip 1 of FIG. 7, pseudo gaps g ′ are formed on both sides of the top of the core chip 1.
Since the pseudo gap g ′ is located away from the medium sliding surface m, the pseudo gap g ′ does not adversely affect the recording / reproducing operation of the magnetic gap G.

[0029]

According to the present invention, the medium sliding contact surface of the core chip in which a pair of ferromagnetic core half bodies each having a metal magnetic film having a high saturation magnetic flux density on the top thereof are joined and integrated, has a magnetic gap and a magnetic gap. The pseudo gap, which is the interface between the core half body and the metal magnetic film, is formed at the tip portion which is formed of the metal magnetic film extending on both sides and is sufficiently separated from the magnetic gap of the medium sliding contact surface. The pseudo gap has almost no influence on the recording / reproducing operation of the magnetic gap, and it is possible to provide a high quality MIG type magnetic head with less noise such as sliding noise and wiggle.

In particular, VT for spherically polishing the top surface of the core chip
In the magnetic head for R, when the top surface of the core chip is spherically polished to form the medium sliding contact surface, the pseudo gap becomes an arc that is not parallel to the magnetic gap, so that the pseudo gap has a bad effect on the magnetic gap. It is possible to provide a stable and high-quality magnetic head for a VTR that can be eliminated more reliably.

Further, since the metal magnetic film forming portion may be only a part of the core chip, the eddy current loss can be reduced as compared with the alloy bulkhead, and the vapor deposition process for forming the metal magnetic film can be performed by the laminate type magnetic head. Shorter than heads, etc.
Also, material cost can be saved.

[Brief description of drawings]

FIG. 1 is a perspective view of a core chip showing a first embodiment of a magnetic head according to the present invention.

FIG. 2 is a plan view of the core chip of FIG. 1 seen from a medium sliding surface.

FIG. 3 is a perspective view of a core in each manufacturing process for explaining the magnetic head manufacturing method according to the present invention.

FIG. 4 is a perspective view of a core chip showing a second embodiment of the magnetic head according to the present invention.

5 is a plan view of the core chip of FIG. 4 seen from the sliding surface of the medium.

FIG. 6 is a perspective view of a core chip showing a third embodiment of the magnetic head according to the present invention.

FIG. 7 is a perspective view of a core chip showing a fourth embodiment of the magnetic head according to the present invention.

FIG. 8 is a perspective view of a core in each manufacturing process for explaining another magnetic head manufacturing method according to the present invention, and FIGS. 8A and 8B include a partially enlarged view of the core.

9 is a perspective view of a core block and a core chip manufactured by the manufacturing process of FIG.

FIG. 10 is a perspective view of a core chip in a conventional MIG type magnetic head.

11 is a plan view of the core chip of FIG. 10 viewed from the sliding surface of the medium.

[Explanation of symbols]

 1 core chip 2 core half body 2'core half body 2 "core half body 3 glass 4 metal magnetic film G magnetic gap m medium sliding contact surface 5 track width groove 7 core base material 9 core block 10 core bar

Claims (3)

[Claims] 1. A core chip in which a pair of ferromagnetic core halves each having a metal magnetic film having a high saturation magnetic flux density on the top thereof are joined and integrated by forming a magnetic gap between the metal magnetic films of the respective core halves. And a medium sliding contact surface that approaches or contacts an external magnetic recording medium of the core chip is formed of the magnetic gap and the surface of the metal magnetic film of each core half extending on both sides thereof. Characteristic MIG type magnetic head. 2. A step of forming a metal magnetic film having a high saturation magnetic flux density on one surface of a core base material of a rectangular ferromagnetic material, and a plurality of tracks parallel to one surface orthogonal to the surface of the metal magnetic film of the core base material. The step of forming the tenter groove, the step of glass-bonding one surface of the pair of core base materials on which the track tenter groove is present to obtain a core block, and the core block is sliced in a direction parallel to the track tenter groove. The method of manufacturing an MIG type magnetic head according to claim 1, further comprising the step of obtaining a plurality of core chips. 3. A step of forming a plurality of tracks for track width increasing parallel to one surface of a core base material of a rectangular ferromagnetic material, and a high saturation magnetic flux density on one surface of the core base material where the track width increasing grooves are present. Of forming a metal magnetic film, a step of slicing a core base material in a direction orthogonal to a track width-grooving groove to obtain a core bar, and a surface of a pair of core bars orthogonal to the track width-growing groove being glass-bonded to form a core block. 2. The method of manufacturing a MIG-type magnetic head according to claim 1, further comprising the step of obtaining the core blocks to obtain a plurality of core chips by slicing the core block in a direction parallel to the track width-growing groove.