JPH10105917A - Thin film magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease an eddy current loss by dividing a magnetic substance middle core penetrating in the plane spiral coil into two or more in parallel in a direction in which magnetic fluxes passes through. SOLUTION: On a substrate 2, a layer consisting of a under core 3 of a magnetic substance and a lower insulation layer 9a, an intermediate insulation layer 9b thereon, and another layer thereon consisting of an upper core of a magnetic substance and an upper insulation layer are laminated. At an end part of the intermediate insulation layer 9b, which is a recording medium sliding face, a recording/reproducing magnetic gap 7 is formed by burying a magnetic substance middle core 6 coupled with an upper core 4 in a recessed part 14, including the under core 3 opposed to the middle core. A magnetic path is formed between the under core 3 and upper core 4 by burying a magnetic substance middle core 5 at a position a fixed length away from the recording medium sliding face 15 in the intermediate insulation layer 9b. A flat coil pattern 8 is spirally formed surrounding the middle core 5. Here, the middle core 5 is divided into two at least excluding the gap in parallel with the magnetic flux passing through.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head for a magnetic recording / reproducing apparatus, and more particularly to a thin film magnetic head for high density magnetic recording.

[0002]

2. Description of the Related Art A conventional thin film magnetic head has a magnetic layer formed by a vacuum thin film forming technique or the like, and is formed by photolithography.
A magnetic circuit has been formed by processing into a predetermined core shape by a method or etching, and forming a magnetic layer via a coil, an insulating layer and the like.

FIG. 3A shows a conventional thin film magnetic head 18.
FIG. 2B is a schematic sectional view taken along the line BB in FIG. 1A. FIG. 4 is an enlarged plan view of the intermediate core 5 of the conventional thin-film magnetic head 18. FIG.
In both figures, on the substrate 2, the lower insulating layer 9a having a groove D ₁ are formed, occurs under the core 3 made of a magnetic material a step in the stacking direction and the lower insulating layer 9a is in a groove D ₁ It is formed without. The intermediate insulating layer 9b is a lower insulating layer 9a
And over the lower core 3. Intermediate insulating layer 9
A concave portion 14 is formed at an end portion (the side of the recording medium sliding surface 15) of the intermediate core 6 b made of a magnetic material.
Are embedded so as to connect to the lower core 3. As a result, a magnetic gap 7 is formed between the intermediate core 6 and the lower core 3. A semicircular through-hole 12 ′ having a diameter of 2 d ₁ is provided inside the intermediate core 6 and the recording medium sliding surface 15 at a distance perpendicular to the recording medium sliding surface 15.
The intermediate core 5 made of a magnetic material is embedded in the through hole 12 ′ so as to be directly connected to the lower core 3. The bottom side m of the through hole 12 ′ is the recording medium sliding surface 1.
5 is formed in parallel. An upper insulating layer 9a is formed on the intermediate cores 5, 6 and the intermediate insulating layer 9b. The upper insulating layer 9a in grooves D ₂ of which is formed such that the groove D ₁ and the same shape of the lower insulating layer 9a, the core 4 upper made of a magnetic material is intermediate insulating layer 9b, on the intermediate core 5 and 6 Is formed. The width 11 of the lower core 3 and the upper core 4 becomes narrower toward the recording medium sliding surface 15, and is narrowed down on the recording medium sliding surface 15 so that high-density recording and reproduction can be performed.
0 is formed. A planar coil pattern 8 is spirally embedded in the intermediate insulating layer 9b around the intermediate core 5. Connection patterns 16 and 17 are formed at the beginning and end of the coil pattern 8.
One end of the coil pattern 8 is connected to an external lead wire 11 through a conductor embedded in a through-hole 10 embedded in the upper insulating layer 9c, and electrically connected to an external device. It is possible.

[0004]

However, in a signal in a high-frequency region, the magnetic permeability in the magnetic material is deteriorated due to the eddy current, and the deterioration is caused by the magnetic material in a direction perpendicular to the direction of the signal magnetic flux passing through the magnetic circuit. This becomes more remarkable as the distance from the surface to the center becomes deeper. That is, the larger the inscribed circle (maximum inscribed circle) among the inscribed circles whose radius is the length connecting the surface of the magnetic body and the center of the magnetic body, the larger the deterioration of the magnetic permeability becomes. Become. Normally, the lower core 3, the upper core 4 and the intermediate core 6 are designed to be thin, so there is no problem. However, the magnetic material thickness of the intermediate core 5 in the direction perpendicular to the flow direction of the signal magnetic flux is sufficient. Therefore, the magnetic permeability is significantly deteriorated due to eddy current loss, and the efficiency of magnetic recording / reproducing is reduced. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a good thin-film magnetic head having a small eddy current loss and a small deterioration in magnetic permeability.

[0005]

A thin-film magnetic head according to the present invention is provided with at least a lower core, an upper core, an intermediate core connecting them, and a magnetic core disposed between the upper core and the lower core. A thin-film magnetic head comprising a magnetic circuit formed by an intermediate core having a gap, wherein the intermediate core is at least two parallel to a direction in which a magnetic flux passes.
It is characterized by being divided into two or more.

According to the present invention, since at least two portions are divided in parallel to the direction of travel of the magnetic flux flowing through the intermediate core, eddy current loss can be reduced, magnetic permeability does not deteriorate, and recording / reproducing does not occur. A decrease in efficiency can be prevented.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a plan view of the thin-film magnetic head 1 of the present invention, and FIG. 1B is a sectional view of the thin-film magnetic head 1 of the present invention taken along line AA. FIG. 2 is an enlarged plan view in which the intermediate core 5 of the thin-film magnetic head of the present invention is divided into intermediate cores 5a and 5b. The same parts as those of the above-described conventional configuration are denoted by the same reference numerals, and description thereof will be omitted. The thin-film magnetic head 1 of the present invention is the same as the intermediate core 5 of the conventional thin-film magnetic head 18.
It is equal to the one divided into two parallel to the direction of travel of the signal magnetic flux flowing through it and parallel to the recording medium sliding surface 15.

In both figures, a groove D ₁ is formed on a substrate 2.
Is lower insulating layer 9a is formed having a the lower core 3 made of a magnetic material is formed without generating a step in the lamination direction and the lower insulating layer 9a is in a groove D _1. The intermediate insulating layer 9b is formed over the lower insulating layer 9a and the lower core 3.
The base m of the semicircle having a diameter of 2d ₁ is formed parallel to the recording medium sliding surface 15. The vertical thickness at the bottom m of the intermediate core 5a are both d _2. A concave portion 14 is formed at an end of the intermediate insulating layer 9b (on the side of the recording medium sliding surface 15), and the intermediate core 6 made of a magnetic material is embedded in the concave portion 14 so as to be connected to the lower core 3. As a result, a magnetic gap 7 is formed between the intermediate core 6 and the lower core 3. Base m spaced inwardly at a distance in the intermediate core 6 and the magnetic recording medium sliding surface 15 in the vertical direction semicircle diameter 2d ₁ by a distance d ₀
Intermediate cores 5 a and 5 b made of a magnetic material are embedded in through holes 12 and 13 formed in two parts in parallel with the lower core 3 so as to be directly connected to the lower core 3. An upper insulating layer 9a is formed on the intermediate cores 5, 6 and the intermediate insulating layer 9b. The core upper made of a magnetic body in a groove D ₂ of the formed such that the groove D ₁ and the same shape of the lower insulating layer 9a upper insulating layer 9a 4
Are formed on the upper insulating layer 9b and the intermediate cores 5 and 6. The width l1 of the lower core 3 and the upper core 4 is the recording medium sliding surface 1
5 to form a track width l0. A planar coil pattern 8 is spirally embedded in the intermediate insulating layer 9b around the intermediate cores 5a and 5b. Connection patterns 16 and 17 are formed at the beginning and end of the coil pattern 8. One end of the coil pattern 8 is connected to an external lead wire 11 through a conductor embedded in a through-hole 10 embedded in the upper insulating layer 9c, and electrically connected to an external device. It is possible. Thus, recording and reproduction can be performed via the magnetic circuit formed by the lower core 3, the upper core 4, the intermediate cores 5a and 5b, and the intermediate core 6.

Here, the relationship between the generation of an eddy current inside the magnetic material and the magnetic permeability in the operation of the thin-film magnetic head 1 in the high frequency region will be considered. In the operation of the thin-film magnetic head 1 in the high-frequency region, the magnetic permeability deteriorates due to the eddy current inside the magnetic material, and this deterioration becomes more remarkable as the closest distance from the magnetic material surface increases. Therefore, if the magnetic circuit is composed of a magnetic material having a reduced thickness in the direction perpendicular to the direction of the signal magnetic flux passing through the magnetic circuit, the eddy current loss is small, and the magnetic permeability is small. You can get a head.

Usually, the lower core 3, the upper core 4, and the intermediate core 6
Is designed to be thin, but the thickness of the intermediate core 5 is designed to be large in order to generate or supply a signal magnetic flux. As a result, the magnetic permeability of the intermediate core 5 deteriorates. In the present invention, since the two divided into the intermediate core 5 intermediate 5a and 5b, the largest circle (maximum inscribed circle) of the circle inscribed in the intermediate core 5a and 5b, the radius d _2/2 (d ₂ <D
₁ ), and the radius d _{1 of the} inscribed circle inscribed in the intermediate core 5
Therefore, eddy current loss can be reduced. Further, since the interval d ₀ is d ₀ << d ₁ , the signal magnetic flux passes through the intermediate cores 5a and 5b.
Since it passes through a cross-sectional area that is substantially the same as that described above, signal flux can be generated or supplied.

As described above, by dividing the intermediate core 5 into the intermediate cores 5a and 5b so as to reduce the maximum inscribed circle, the eddy current loss can be reduced, the magnetic permeability is less deteriorated, and the recording efficiency and reproduction are reduced. An efficient thin-film magnetic head can be obtained.

In the present invention, the intermediate core 5 is divided into two equal parts in the direction parallel to the signal magnetic flux and parallel to the sliding surface 15 of the recording medium. However, the intermediate core 5 may be divided into a plurality of parts of an arbitrary size. . The same effect can be obtained by dividing the intermediate core 5 in the direction parallel to the signal magnetic flux and in the vertical direction.

[0013]

According to the thin-film magnetic head of the present invention,
Since the intermediate core is divided into at least two or more, the eddy current loss is small, the deterioration of the magnetic permeability can be reduced, and a thin-film magnetic head with good recording and reproducing efficiency can be obtained.

[Brief description of the drawings]

FIG. 1A is a schematic plan view of a thin-film magnetic head according to the present invention, and FIG. 1B is a schematic sectional view taken along the line AA in FIG.

FIG. 2 is an enlarged plan view of an intermediate core divided into two parts of the thin-film magnetic head of the present invention.

FIG. 3A is a schematic plan view of a conventional thin-film magnetic head, and FIG. 3B is a schematic cross-sectional view taken along the line BB of FIG.

FIG. 4 is an enlarged plan view of an intermediate core of a conventional thin film magnetic head.

[Explanation of symbols]

 Reference numerals 1, 18: thin-film magnetic heads 2, substrate 3, lower core 4, upper core 5, 5a, 5b, 6, intermediate core 7, magnetic gap 8, coil pattern 9a, lower insulating layer 9b, intermediate insulating layer 9c, upper part Insulating layer 10 ... Through hole 11 ... External lead wire 12, 13 ... Through hole 14 ... Depression 15 ... Recording medium sliding surface 16, 17 ... Connection pattern

Claims (1)

[Claims] 1. A magnetic circuit formed by at least a lower core, an upper core, an intermediate core connecting them, and an intermediate core disposed between the upper core and the lower core and having a magnetic gap. Wherein the intermediate core is divided into at least two parts in parallel with a direction in which a magnetic flux passes.