JPH08102007A - Magnetic head - Google Patents

Abstract

(57) [Summary] [Purpose] To suppress the occurrence of sliding noise and improve output characteristics and joint strength. [Structure] The magnetic cores 1 and 2 are configured by sequentially arranging a single crystal ferrite, a polycrystalline ferrite, and a single crystal ferrite in the depth direction of the front gap g ₁ from the medium sliding surfaces 1b and 2b side. Forming part 1
3, 14 and the back gap forming portions 17, 18 are made of single crystal ferrite. At this time, the winding groove forming portions 15 and 16 may be made of polycrystalline ferrite. Further, it is also applicable to a metal-in-gap head in which a metal magnetic film is formed at least in the magnetic gap forming portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head in which a pair of magnetic cores are joined and integrated by forming a front gap and a back gap between opposed surfaces, and more specifically, noise characteristics, output characteristics, and joint strength. To a magnetic head excellent in

[0002]

2. Description of the Related Art As a magnetic head mounted on a magnetic recording / reproducing apparatus such as a video tape recorder, for example, a magnetic head having a structure as shown in FIG. That is, the winding grooves 103, 104 are formed on the facing surfaces 101a, 102a.
A pair of magnetic cores 101 and 102, which are formed respectively, are joined and integrated by forming a front gap G ₁ and a back gap G ₂ which function as recording and reproduction between the facing surfaces 101a and 102a.

In such a magnetic head, single crystal ferrite or polycrystalline ferrite is used as a constituent material of the magnetic cores 101 and 102. However, when single crystal ferrite is used, sliding noise becomes large. Tends to be easy. Therefore, in recent years, it has been proposed to use a bonding material of single crystal ferrite and polycrystalline ferrite as a magnetic core constituent material. It is considered that this sliding noise is caused by the magnetization of the magnetic core changing by the inverse magnetostriction effect due to the stress during sliding with the medium. This is also because polycrystals having a random crystal orientation cancel the inverse magnetostriction effect to some extent, and it is considered that sliding noise is reduced.

As a magnetic head using a magnetic core made of the above-mentioned bonding material, for example, one shown in FIG. 9 has been proposed. The magnetic head is a magnetic head having substantially the same configuration as the magnetic head shown in FIG. 8, and the magnetic cores 111 and 112 have medium sliding surfaces 111b and 1b.
It is assumed that the single crystal ferrite and the polycrystalline ferrite shown by the shaded area in the figure are sequentially arranged in the depth direction of the front gap G ₃ from 12b. Only the front gap G ₃ forming portion is composed of the single crystal ferrite, and the rest. The part is composed of polycrystalline ferrite.

A magnetic head using a magnetic core made of single crystal ferrite as shown in FIG.
When a magnetic head using a magnetic core made of a bonding material of single crystal ferrite and polycrystalline ferrite as shown in FIG.
The value using the single crystal ferrite was 3.6 dB, while the value using the bonding material was 2.0 dB.

[0006]

However, the magnetic head using the bonding material of the single crystal ferrite and the polycrystalline ferrite as described above has the following disadvantages. That is, in the above magnetic head, the front gap G ₃ forming portion of the magnetic core is made of single crystal ferrite, and the back gap G ₄ forming portion is made of polycrystalline ferrite. In the case of polycrystalline ferrite, various crystal planes are integrated on one plane. Therefore, if polishing processing similar to that of single crystal ferrite is performed, a grain boundary step is generated and surface roughness deteriorates.

The inventors of the present invention measured the surface roughness of each material when the single crystal ferrite and the polycrystalline ferrite were polished under the same conditions, and found that the maximum roughness of the single crystal ferrite was 10 Å. On the other hand, the maximum roughness of the polycrystalline ferrite was 200 angstrom. Therefore, in the magnetic head as described above, the surface roughness of the gap forming surface of the back gap G ₄ is not so good that the desired gap size cannot be obtained, and the characteristics deteriorate due to the formation of the work-affected layer. Alternatively, there is an inconvenience such as a decrease in the bonding strength between the magnetic cores.

Further, since the surface roughness of the back gap G ₄ gap forming surface is inferior to that of the front gap G ₃ of the gap forming surface, a loss is generated in the back gap G _{4 and} an improvement in output is hindered. In addition, there is a problem that the bonding strength of the magnetic head itself is lowered. Therefore, the present invention has been proposed in view of conventional circumstances, and an object of the present invention is to provide a magnetic head in which generation of sliding noise is suppressed and which has excellent output characteristics and bonding strength.

[0009]

In order to achieve the above-mentioned object, the present invention provides a magnetic head in which a pair of magnetic cores are joined and integrated by forming a front gap and a back gap between opposing surfaces. The magnetic core is composed of a single crystal ferrite, a polycrystalline ferrite, and a single crystal ferrite sequentially arranged in the depth direction from the medium sliding surface side.
The front gap and the back gap are formed of single crystal ferrite.

In the magnetic head of the present invention, the winding grooves are formed on the facing surfaces of the pair of magnetic cores, and the polycrystalline ferrite is arranged according to the depth of the winding grooves of the magnetic core. Preferably. Further, in the magnetic head of the present invention, the metal magnetic film may be formed on at least the front gap forming portion and the back gap forming portion of the facing surfaces of the pair of magnetic cores.

[0011]

In the magnetic head of the present invention, the magnetic core is constructed by sequentially arranging the single crystal ferrite, the polycrystalline ferrite, and the single crystal ferrite in the depth direction from the medium sliding surface side to form the front gap and the back gap. Since the part is made of single-crystal ferrite, the surface roughness of the front gap forming surface and the back gap forming surface become equal, and loss occurs on one side to hinder the improvement of the output of the magnetic head or to reduce the bonding strength of the magnetic head itself. Is unlikely to happen. Further, since the polycrystalline ferrite is also arranged, the generation of sliding noise is suppressed by the polycrystalline ferrite portion.

In the magnetic head of the present invention, the winding grooves are formed on the facing surfaces of the pair of magnetic cores, and the polycrystalline ferrite is arranged according to the depth of the winding grooves of the magnetic core. If so, the winding groove forming portion is made of a single material, and the processing of the winding groove is easy.

[0013]

Embodiments of the magnetic head to which the present invention is applied will be described below in detail with reference to the drawings. In the magnetic head of this embodiment, as shown in FIG. 1, a magnetic gap g ₁ (hereinafter referred to as front gap g ₁ ) in which a pair of magnetic cores 1 and 2 function as recording / reproducing between opposed surfaces 1 a and 2 a. A magnetic gap g ₂ (hereinafter, referred to as a back gap g ₂ ) other than that is formed and joined and integrated.

Track width regulating grooves 3 and 4 for regulating the widths of the front gap g ₁ and the back gap g ₂ are formed on the facing surfaces 1a and 2a, respectively, and winding grooves 5 and 6 are also formed, respectively. Glass grooves 7 and 8 are also formed respectively. The fused glass 9 is melted and filled in the groove portion formed between the track width regulating grooves 3 and 4 and the winding grooves 5 and 6, and the glass groove 7 is formed between the track width regulating grooves 3 and 4.
The fused glass 10 is also melt-filled in the groove portion formed between the magnetic cores 1 and 2, and the magnetic cores 1 and 2 are joined and integrated.

Winding auxiliary grooves 11 and 12 are provided at positions facing the winding grooves 5 and 6, and the medium sliding surfaces 1b and 2b are provided.
A step is formed on the side to regulate the width of contact with the medium. Then, in the magnetic head of the present embodiment, as shown in FIG.
A single crystal ferrite, a polycrystalline ferrite, and a single crystal ferrite are sequentially arranged in the depth direction of the front gap g ₁ from the side b, and the front gap forming portion 1 is formed.
3, 14 are made of single crystal ferrite, winding groove forming portions 15 and 16 shown by hatched portions in the drawing are made of polycrystalline ferrite, and back gap forming portions 17 and 18 are made of single crystal ferrite.

That is, in the magnetic head of this embodiment, the front gap g ₁ and the back gap g ₂ formation surface of the facing surfaces 1a and 2a of the pair of magnetic cores 1 and 2 is made of single crystal ferrite. Become. Therefore, the surface roughness of the front gap forming surface becomes equal to the surface roughness of the back gap forming surface, and it is difficult for the loss in one side to hinder the improvement of the output of the magnetic head or to reduce the bonding strength of the magnetic head itself. The output characteristics and bonding strength of the magnetic head of the example are good.

Further, in the magnetic head of this embodiment,
The winding groove forming portions 15 and 16 are made of polycrystalline ferrite, and the polycrystalline ferrite portion suppresses the generation of sliding noise. The magnetic head of this embodiment is manufactured as follows. That is, first,
A magnetic head core substrate 21 as shown in FIG. 3 is prepared. In the magnetic head core substrate 21, the polycrystalline ferrite material 23 shown by the hatched portion in the drawing is a single crystal ferrite material 22,
It is sandwiched by 24.

At this time, the polycrystalline ferrite material 23
The thickness indicated by A in the drawing is adjusted to the depth of the winding groove indicated by B in the drawing of the winding grooves 5 and 6 of the magnetic head of the present embodiment shown in FIG. Further, it is preferable to set the thickness A of the polycrystalline ferrite material 23 to be smaller than the depth dimension B of the winding groove in consideration of a processing error. Further, in order to suppress the generation of sliding noise, it is preferable that the thickness A of the polycrystalline ferrite material 23 is 100 μm or more.

Subsequently, as shown in FIG. 4, a winding groove 25 and a glass groove 26 are formed on one main surface 21a of the magnetic head core substrate 21. At this time, the winding groove 25 is formed in the polycrystalline ferrite material 23 of the magnetic head core substrate 21, and the shape of the winding groove 25 restricts the depth of the front gap g _1. The side surface 25a on the g ₁ side is assumed to be an inclined surface. On the other hand, the glass groove 26 is formed in the single crystal ferrite 24 on the back gap g ₂ side.

Then, a plurality of track width regulating grooves 27 are formed on the one main surface 21a of the magnetic head core substrate 21 at a predetermined pitch in a direction orthogonal to the winding grooves 25 and the glass grooves 26. Subsequently, the one main surface 21a in which the above-mentioned grooves are formed is mirror-finished, and this is divided into two to obtain a pair of magnetic core blocks 28 and 29 as shown in FIG. Next, the mirror-finished facing surfaces 28a, 2 of the pair of magnetic core blocks 28, 29.
A gap film (not shown) made of a non-magnetic material such as SiO _{2 is} formed in the gap forming portion 9a to form a predetermined gap length.

Then, as shown in FIG. 6, the track width regulating grooves 30, 31 of the pair of magnetic core blocks 28, 29, the winding grooves 32, 33, and the glass grooves 34, 35 are aligned with each other, A fused glass rod is placed in the groove portion formed between the winding grooves 32 and 33 and the groove portion formed between the glass grooves 34 and 35 to be melted, and as shown in FIG. The fusion glass 36 is melt-filled in the groove portion formed between the winding grooves 32 and 33, and the fusion glass 37 is inserted in the groove portion formed between the track width regulating grooves 30 and 31 and the glass grooves 34 and 35. Melt-filled, magnetic core block 2
8 and 29 are joined and integrated.

Next, the medium sliding surface of the magnetic core block joined and integrated is cylindrically polished, and a step is formed to control the width of contact with the medium while tilted by a predetermined azimuth angle, and the chip is cut. Then, the magnetic head of this embodiment as shown in FIGS. 1 and 2 is obtained. As an example of the magnetic head to which the present invention is applied, in addition to the above-mentioned one, a metal magnetic film is formed at least in the magnetic gap forming portion,
Examples of metal-in-gap heads (so-called MIG heads) are also given.

That is, for example, as shown in FIG. 7, it has substantially the same structure as the above-mentioned magnetic head, and the metal magnetic films 43 and 44 are formed on the facing surfaces 41a and 42a of the pair of magnetic cores 41 and 42, respectively. One of them is formed respectively, and a front gap g ₃ and a back gap g ₄ are formed between the metal magnetic films 43 and 44. In the magnetic head as shown in FIG. 7, the magnetic cores 41, 42
Opposing surfaces 41a and 42a are provided in parallel to the front gap g ₃ and the back gap g ₄ , and the metal magnetic films 43 and 44 are provided thereon.

When manufacturing such a magnetic head,
The magnetic head may be manufactured according to the manufacturing method described above, and a step of forming a metal magnetic film on the mirror-finished surface of the magnetic core block by vacuum thin film forming means such as sputtering may be added. The present invention can also be applied to an MIG head in which the facing surfaces of a pair of magnetic cores are not parallel to the magnetic gap.

[0025]

As is apparent from the above description, the magnetic head of the present invention is a magnetic head in which a pair of magnetic cores are joined and integrated by forming a front gap and a back gap between opposing surfaces. The magnetic core is configured by sequentially arranging single crystal ferrite, polycrystalline ferrite, and single crystal ferrite in the depth direction from the medium sliding surface side. Since the front gap and the back gap forming portion are made of single crystal ferrite, The surface roughness of the gap forming surface becomes equal to that of the back gap forming surface, and it is difficult for the loss in one side to hinder the improvement of the output of the magnetic head and the lowering of the bonding strength of the magnetic head itself. The strength is good.
Further, since the polycrystalline ferrite is also arranged, the generation of sliding noise is suppressed by the polycrystalline ferrite portion.

In the magnetic head of the present invention, the winding grooves are formed on the facing surfaces of the pair of magnetic cores, and the polycrystalline ferrite is arranged according to the depth of the winding grooves of the magnetic core. If so, the winding groove forming portion is made of a single material, and the processing of the winding groove is easy.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a magnetic head to which the present invention is applied.

FIG. 2 is a side view schematically showing an embodiment of a magnetic head to which the present invention is applied.

FIG. 3 is a perspective view showing a method of manufacturing an embodiment of a magnetic head to which the present invention is applied, in the order of steps, and showing a step of preparing a magnetic head core substrate.

FIG. 4 shows a method of manufacturing an embodiment of a magnetic head to which the present invention is applied in the order of steps, and is a perspective view showing a step of forming a winding groove, a glass groove, and a track width regulation groove on a core substrate for a magnetic head. It is a figure.

FIG. 5 is a perspective view showing the method of manufacturing the magnetic head according to the embodiment of the present invention in the order of steps, and showing steps of forming a pair of magnetic core blocks.

FIG. 6 is a perspective view showing a method of manufacturing an embodiment of a magnetic head to which the present invention is applied in the order of steps, and showing a step of joining and integrating a pair of magnetic core blocks.

FIG. 7 is a perspective view showing another embodiment of the magnetic head to which the present invention is applied.

FIG. 8 is a perspective view showing an example of a conventional magnetic head.

FIG. 9 is a perspective view showing another example of a conventional magnetic head.

[Explanation of symbols]

1, 2, 41, 42 Magnetic cores 1a, 2a, 41a, 42a Opposing surfaces 1b, 2b Medium sliding surface 5,6 Winding groove 13,14 Front gap forming portion 15,16 Winding groove forming portion 17,18 Back Gap forming part 43,44 Metal magnetic film g ₁ , g ₃ Front gap g ₂ , g ₄ Back gap

Claims (3)

[Claims] 1. A magnetic head in which a pair of magnetic cores are joined and integrated by forming a front gap and a back gap between facing surfaces, wherein the magnetic cores are made of single crystal ferrite in the depth direction from the medium sliding surface side. A magnetic head comprising a polycrystalline ferrite and a single crystal ferrite sequentially arranged, and a front gap and a back gap forming portion made of the single crystal ferrite. 2. A winding groove is formed on the facing surface of a pair of magnetic cores, and a polycrystalline ferrite is arranged according to the depth dimension of the winding groove of the magnetic core. Item 1. The magnetic head according to Item 1. 3. A metal magnetic film is formed on at least a front gap forming portion and a back gap forming portion of opposing surfaces of a pair of magnetic cores.
The magnetic head described.