JPH07121814A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To obtain a magnetic head with which high-frequency signal for high- definition VTR digital VTR, etc., can be efficiently recorded and reproduced. CONSTITUTION:In a ring-type magnetic head with a magnetic layer 3 held between nonmagnetic substrates 4 on both sides of the magnetic layer 3, when high-frequency current flows to the wire 7, eddy current is generated in a metallic magnetic layer 3 and by the current loss of the eddy current, heat is generated around the magnetic gap 10 of the metal magnetic layer 3 to cause heat treatment as if externally applied with heat. A magnetic field is generated and heat treatment is executed in the magnetic field by disposing a magnet 8 around the magnetic head or by, in the second invention, by allowing the high-frequency current to flow to the wire 7, the magnetic field itself is concentrated near the magnetic gap 10. Thereby, in the metal magnetic layer 3 near the magnetic gap 10, an easily magnetized axis 9 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 suitable for efficiently recording and reproducing a high frequency signal such as a high definition VTR or a digital VTR, and a method of manufacturing the magnetic head.

[0002]

2. Description of the Related Art In recent years, a system for handling a wide band signal such as a high definition VTR or a digital VTR has been actively developed, and a magnetic head having a high saturation magnetic flux density and an excellent frequency characteristic is also used as a magnetic head. Development is desired.
Currently, a magnetic head using a metal magnetic material having a high saturation magnetic flux density is being developed, but its high frequency characteristics are restricted by the snook limit line due to ferromagnetic resonance.

[0003]

In a system for handling a wide band signal such as a high definition VTR or a digital VTR, a core material for a magnetic head is required to have a high initial permeability in a high frequency band. However, the high frequency characteristics of the initial magnetic permeability of most magnetic films are restricted by the Snook limit line due to ferromagnetic resonance, and the initial magnetic permeability is 500 or less in the frequency band of 30 MHz or more.

Therefore, if such a non-oriented magnetic film is used as a head core, it is difficult to realize a high-performance head compatible with the above high frequency system.

On the other hand, the initial magnetic permeability characteristics of a multilayer film in which amorphous magnetic films having uniaxial anisotropy are laminated with their easy magnetization axis directions aligned are low in initial magnetic permeability characteristics in all frequency bands when measured in the easy magnetization axis direction. On the other hand, when measured in the direction of the hard axis, high permeability is maintained up to high frequencies. Therefore, if a magnetic path is formed only in the hard axis direction, a head with high reproduction efficiency can be realized up to high frequencies. However, in a ring type head such as a video head, it is not possible to configure the magnetic path only in the hard axis direction. Is extremely difficult in the manufacturing process.

In view of such circumstances, an object of the present invention is to provide a high frequency magnetic head capable of recording / reproducing at a sufficiently high rate even in a high frequency band of 30 MHz or more, and a manufacturing method thereof.

[0007]

In order to achieve the above object, the present invention is a ring-type magnetic head in which both sides of a metal magnetic film are sandwiched by non-magnetic substrates, and magnetic anisotropy is provided only near the magnetic gap. The magnetic head is characterized by being controlled. Further, the manufacturing method thereof includes a step of causing a high-frequency current to flow in a winding to generate an eddy current in the metal magnetic film to heat the periphery of the magnetic gap of the metal magnetic film to perform heat treatment in a magnetic field. A method for manufacturing a head, wherein in the first invention, a magnetic field is generated by disposing a magnet around the magnetic head,
A second aspect of the invention is characterized in that the magnetic field generated by passing a high-frequency current through the winding is concentrated near the gap to generate the magnetic field.

[0008]

According to the present invention, an eddy current is generated in the metal magnetic film by passing a high frequency current through the winding, and the eddy current loss causes heat to be generated in the vicinity of the magnetic gap of the metal magnetic film. It seems to have been given. At this time, in the first invention, the magnetic field is generated by arranging the magnet around the magnetic head, and in the second invention, by concentrating the magnetic field itself generated by passing the high frequency current in the winding near the gap. By generating and performing heat treatment in a magnetic field, magnetic anisotropy is provided in the vicinity of the magnetic gap of the metal magnetic film to form an easy axis of magnetization, and a high-performance magnetic head having excellent high frequency characteristics can be realized.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view of a magnetic head for explaining the structure of a magnetic head and its manufacturing process in an embodiment of the first invention of the present invention. As shown in FIG. 1, a magnesium magnetic titanate-based non-magnetic substrate 4 is provided on both sides of a metal magnetic layer 3 in which a metal magnetic film 1 made of a Co-based amorphous alloy and an insulating film 2 made of SiO ₂ are alternately laminated. It has a sandwiched structure. Adhesion between the metal magnetic layer 3 and the non-magnetic substrate 4 is performed with the adhesive glass 5. A winding window 6 is provided with a winding 7. High frequency current in winding 7 (100MHz, 200m
A, 10 minutes), the magnetic gap of the metal magnetic layer 3
Heat is generated in the vicinity of the magnetic head 10, and heat treatment in a magnetic field is performed by a magnetic field generated from a magnet 8 arranged around the magnetic head, magnetic anisotropy is imparted to the metal magnetic layer 3 in the vicinity of the magnetic gap 10, and the easy axis 9 of magnetization is formed. It is formed.

FIG. 2 is a perspective view of the magnetic head for explaining the structure of the magnetic head and the manufacturing process thereof according to the second embodiment of the present invention. As shown in FIG. 2, both sides of a metal magnetic layer 3 in which a metal magnetic film 1 made of a Co type amorphous alloy and an insulating film 2 made of SiO ₂ are alternately laminated are formed of a magnesium titanate type non-magnetic substrate 4. It has a sandwiched structure. Adhesion between the metal magnetic layer 3 and the non-magnetic substrate 4 is performed with the adhesive glass 5. A winding window 6 is provided with a winding 7. High frequency current (100MHz, 500
(mA, 10 minutes) so that the magnetic field concentrates, and the metal magnetic layer 3
The heat treatment in the magnetic field is performed by the magnetic field generated by concentrating the magnetic field itself generated in the vicinity of the magnetic gap 10 in the vicinity of the magnetic gap 10 by causing the magnetic field generated by the current flowing in the winding 7 to concentrate in the vicinity of the magnetic gap 10. Magnetic anisotropy is given to 3 and the easy axis 9 is formed.

The magnetic head manufactured by the above method is
A magnetic field is applied during heat treatment to create a magnetic gap
An easy axis 9 is formed in the vicinity of 10, and a high-performance magnetic head having excellent high frequency characteristics can be realized.

FIG. 3 shows the relative output frequency characteristics of the magnetic head (a) on which the easy axis of magnetization is formed by the manufacturing method of the present invention and the magnetic head (b) using the conventional non-oriented laminated metal magnetic film. . It can be seen that at a high frequency of 30 MHz or higher, the magnetic head of the present invention exhibits high frequency characteristics that greatly exceed those of the conventional magnetic head.

[0013]

As described above, according to the magnetic head and the method of manufacturing the same of the present invention, it is possible to easily obtain a high frequency magnetic head capable of recording and reproducing with sufficiently high efficiency even in a high frequency band of 30 MHz or more.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic head illustrating a configuration of a magnetic head and a manufacturing process thereof according to an embodiment of the first aspect of the present invention.

FIG. 2 is a perspective view of the magnetic head for explaining the structure of the magnetic head and the manufacturing process thereof according to the second embodiment of the present invention.

FIG. 3 is a diagram showing frequency characteristics of relative outputs of a magnetic head according to the present invention and a conventional magnetic head.

[Explanation of symbols]

1 ... Metal magnetic film, 2 ... Insulating film, 3 ... Metal magnetic layer,
4 ... Non-magnetic substrate, 5 ... Adhesive glass, 6 ... Winding window,
7 ... Winding, 8 ... Magnet, 9 ... Easy axis of magnetization, 10 ... Magnetic gap.

Claims (7)

[Claims] 1. A ring-type magnetic head in which both sides of a metal magnetic film are sandwiched between non-magnetic substrates, wherein magnetic anisotropy is controlled only in the vicinity of a magnetic gap of the magnetic head. 2. A ring-type magnetic head in which both sides of a metal magnetic film are sandwiched by non-magnetic substrates, a step of arranging at least one magnet around the magnetic head, and a high-frequency current flowing in a winding of the magnetic head. A step of generating an eddy current in the metal magnetic film to heat the metal magnetic film for heat treatment. 3. In a ring type magnetic head having a non-magnetic substrate sandwiching both sides of a metal magnetic film, a high frequency current is passed through a winding so that a magnetic field is concentrated in the vicinity of a magnetic gap to generate an eddy current in the metal magnetic film. A method of manufacturing a magnetic head, comprising a step of heating the metal magnetic film to heat-treat it. 4. The magnetic head according to claim 1, wherein the metal magnetic film is a laminated film of the metal magnetic film and an insulating film. 5. The method of manufacturing a magnetic head according to claim 2, wherein the metal magnetic film is a laminated film of the metal magnetic film and an insulating film. 6. The magnetic head according to claim 4, wherein the metal magnetic film is an amorphous magnetic film. 7. The method of manufacturing a magnetic head according to claim 5, wherein the metal magnetic film is an amorphous magnetic film.