JPH01227206A - Magnetic head - Google Patents

Abstract

PURPOSE:To make the thermal expansion coefficient of layer insulators of multilayer structure close to the coefficient of a metallic material by making the layer mainly out of an oxide of Al and Si and including simultaneously the crystal phases of both cristobalite and mullite by the oxide of Al and Si. CONSTITUTION:A substrate material is mirror-finished to form a substrate 1, Ar is led into a pressure reducing vessel, a sputtering is performed by using a target of composition CoSiNb13Zr6 and a noncrystalline alloy film 2a is manufactured. Next, when powder of composition in which the weight inclusion ratio of Al2O3 to SiO2 is 40:60 is calcined, crushed, formed and baked to manufacture a target, the mullite and the cristobalite coexist in its composition and a thermal expansion coefficient alpha becomes 115X10<-7>/ deg.C. Next, a layer insulating material 3 is made on the noncrystalline alloy film 2a by a spatter by using the target, and a block of three-layer structure is obtained with the noncrystalline alloy film and the layer insulating material as 2b, 3b and 2c alternately in the same way. Next, a laminated core is obtained by joining the substrate 1 and a substrate 5 made of the same material through an adhesive glass layer 4, a coil window 6 is processed and after that, laminated core half- bodies 1'-5' of the same structure are joined 7 together.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a magnetic head used in the electrical and electronic industries.

Conventional technology Ferrite has been widely used as a core material for magnetic heads due to its good abrasion resistance.
Since the saturation magnetic flux density Bs is 30 to 50% lower than that of alloy materials, high-density metals that have appeared in recent years.

When used for high-density recording media with coercive force, magnetic saturation of the head core becomes a problem.From this perspective, magnetic heads using alloy materials such as permalloy and sendust are recommended as heads compatible with high-density recording media. It has been put into practical use.

On the other hand, amorphous alloys have been attracting attention as materials with excellent wear resistance and magnetic properties. These alloy materials,
When used as a magnetic helad core material, the resistivity of the material itself is as low as 70 to 120 .mu..OMEGA.Cm, resulting in large losses due to eddy currents in the high frequency region, so improvements are usually made by using a laminated structure.

In audio heads, the track width is several hundred microns.
Since the frequency range is low, the thickness of each core is as thick as 200 to 300 μm, and so-called adhesives such as ebo-shi resin are used for lamination and gap formation.

However, when it comes to magnetic heads for videos, computers, and measuring instruments, the track width is small (for example, several tens of μm).
), and the gap length is very short (for example, 0.3 μm or less), so it is difficult to maintain a highly accurate gap in a magnetic head configuration using adhesive.

In addition, the track width is small (and the frequency range used is several MH)
Since the frequency is as high as 10 MHz or 10 MHz, the thickness of each core is preferably 10 μm or less.

It is difficult to produce a magnetic core of such thickness from so-called bulk materials using current processing technology, and even with ribbon amorphous or ribbon Sendust produced by ultra-quenching, it is difficult to obtain a magnetic core with a uniform thickness at a thickness of 20 μm or less. That's difficult.

Therefore, from the above point of view, methods have been adopted in which magnetic materials such as amorphous alloys and sendust alloys are made into thin plates by sputtering or vapor deposition. According to these methods, it is easy to obtain cores with a thickness of 10 μm or less per sheet, and it is also possible to alternately laminate magnetic materials and interlayer insulating materials, and the adhesion strength between each material is strong. , it is possible to maintain the high precision gap.

It is well known that SiO2 is used as the interlayer insulating material at this time (Trans.
, IECE'74/9 Vol.

57-CNo.9. Institute of Electrical Engineers of Japan study group material MAG82-3
6). It is also known to use SiO2 as a gap spacer material.

Problems to be Solved by the Invention The conventional metal magnetic material and the eyebrow insulating material S
In a magnetic head made of a laminated iO2 magnetic core, there was a tendency for the magnetic permeability μ to decrease when the number of laminated layers was increased, even though the thickness of the magnetic material was the same.

This means that the magnetostriction constant λS of the metallic magnetic material is not completely zero, but it is also one order of magnitude larger than the thermal expansion coefficient α (α: 4X10-”/'C) of SiO2. (α of metal magnetic material: 110-15
0xlO-7/°C).

In addition, using a magnetic head made of a laminated magnetic core of metal magnetic material and 5i02, which is an insulating material between the eyebrows, we conducted tape running tests under various environments using a commercially available coated metal tape. A large decrease was observed.

When we observed the tape sliding surface of the magnetic head where the output had decreased, we found that there was selective deposits near the SiO2 interlayer insulating material, and the extent of this was measured using a step meter and found to be a maximum of 500 to 600 A. . When this deposit was analyzed by Auger analysis, it was found that the adhered component was a magnetic material component in the metal tape, and the value determined by the step meter and the depth determined by Auger analysis matched. In addition, some deposits were also observed on the gap, although to a lesser extent.

As described above, when a coated metal tape is run in a low humidity environment, the magnetic material in the metal tape selectively adheres to the vicinity of SiO2, which is the interlayer insulating material of the magnetic head using a metal magnetic material, and this adhered material It was found that a gap was created between the head and the tape, resulting in a spacing loss and a decrease in head output.

Means for Solving the Problems In a magnetic head made of a magnetic material with a multilayer structure, the glabella insulating material of the multilayer structure is mainly composed of oxides of aluminum and silicon, and the oxides of aluminum and silicon are composed of cristobalite and mullite. It is configured to contain both crystal phases at the same time.

Effects of the present invention With the above configuration, the coefficient of thermal expansion of the glabella insulating material is greater than that of SiO2 or Al2O3 by more than an order of magnitude, and is closer to the coefficient of thermal expansion of the metal magnetic material. The influence of stress on the magnetic material is reduced, and deterioration of magnetic head characteristics is reduced.

In addition, silicon oxide is not used in the form of SiO2 alone,
By using it as mullite (2A1203.3SiOz), the adhesion of magnetic powder from the magnetic tape to the interlayer insulation material is also reduced.

Example An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

A commercially available substrate material was polished to a mirror surface, thoroughly cleaned, and used as substrate 1. After evacuating the inside of the vacuum chamber to 3X10-7 Torr,
An amorphous alloy film 2a having a thickness of 10 μm was produced by introducing r gas to a pressure of 2×10 −3 Torr and sputtering using a target having a compositional formula of CoaINbz3Zrs.

Next, alumina (A 1203) and silica (Si02)
Powder with a composition of 40/60 in the content ratio (wt%) of 130
It was calcined at 0°C, pulverized with a ball mill, dried, granulated, molded, and fired at 1450 to 1500°C to produce a target. When this target was analyzed by X-rays, it was found that the crystal structures of mullite and cristobalite coexisted.

Furthermore, when we measured the thermal expansion coefficient α of this target, we found that
α was 115×10−7/°C. Next, using this target, Ar pressure 4X was applied onto the amorphous alloy ll2a.
A glabellar insulating material 3a of about 1000 A was produced by sputtering at 10" Torr. Note that the interlayer insulating material formed by sputtering of the present invention contained both mullite and cristobalite at the same time due to X-M. .

Similarly, the amorphous alloy film and the glabella insulating material are alternately applied to 2b.
, 3b, and 2c to obtain a block having a three-layer structure of amorphous alloy films.

A substrate 5 made of the same material as the other substrate 1 was bonded via an adhesive glass layer 4 to obtain a laminated core.

Next, after processing the winding window 6 on the gap abutting surface, the abutting surface is processed into a mirror surface with diamond paste, and then a gap spacer material is sputtered to a predetermined thickness on this surface, completing one side for gap formation. do.

This block was abutted against a half-laminated core having the same structure of 1' to 5°, and a gap was formed using adhesive glass 7.

A predetermined head was cut out from this pair of rods to complete a magnetic head.

These magnetic heads are used in video tape recorders (VTRs).
The head/tape relative speed was 3.8 m/sec), and tape running tests were conducted under various environments using a commercially available coated metal tape. In contrast to the fact that a significant drop in magnetic head output was observed in a low humidity environment, a magnetic head made of the material of the present invention as a glabellar insulator or a gap material could provide stable output in all environments. Ta.

Table 1 shows the head output of the head of the present invention and, for reference, a conventional magnetic head at 23 DEG C. and 10% relative humidity. Note that the magnetic head output is expressed as 0 (dB) at 23° C. and 70% relative humidity.

(Margin below) Table - Table For comparison, the same composition of alumina and silica was prepared.

The shape was fired at 1300℃, and its crystal structure became mullite (
Table 1 shows the output of a magnetic head manufactured using a target having a thermal expansion coefficient α: 20×10 −7 /° C.).

Next, non-magnetic stainless steel was used for the substrate, and Sendust alloy (
Targeting Fe84.5, Si9.7, and A15.8% by weight, the inside of the vacuum chamber was evacuated to 5 x 10'' Torr, and then Ar gas was introduced to 15 x 10-3 Torr.
It was sputtered as r r. Next, using an interlayer insulating material composed of mullite/cristobalite as a target, an Ar pressure of 4x10-2 Torr was applied to the sendust film.
A film of about 1000 A of living room insulation material was formed by sputtering at r.

Similarly, the sendust alloy film and the interlayer insulating material were alternately laminated to produce a multilayer sendust film. The film thus obtained was subjected to an external magnetic field of 1 m0 at a frequency of 100 kHz.
The magnetic permeability at e is shown in Table 2. In addition, the magnetic permeability in the table is shown with respect to the thickness of the magnetic material, that is, the interlayer insulating material is ignored.

Table 2 In the above embodiment, a magnetic head having a sandwich structure in which a head core is sandwiched between substrates was described, but the tape sliding surface does not include a substrate, that is, the tape sliding surface is entirely made of a multilayer magnetic structure. A magnetic head made of a body also has similar effects.

In addition, as for magnetic materials, although the amorphous alloy Co-Nb-Zr system has been described, other systems such as Co-Fe-3i-B, N
A similar effect can be achieved with i-3i-B systems, and is not limited to sputtering materials (it is also possible to use ribbon amorphous materials using ultra-quenching methods, vapor deposition methods, etc.).

There are no particular compositional limitations for sendust alloys (, Fe
-5i-A1 alloy composition is effective. Similar effects can be expected for permalloy (Fe--Ni alloy), which is a magnetic alloy material, since magnetic permeability has a particularly large influence on magnetostriction.

Effects of the Invention According to the present invention, in a magnetic head made of a multilayered magnetic material, the glabella insulating material or the gap material contains S in which crystal phases of both mullite and cristobalite coexist.
By using a material mainly composed of iO2/AI20s, the coefficient of thermal expansion is more than an order of magnitude larger than that of conventional materials (,
Since it is closer to a metallic magnetic material, the effect of stress on the magnetic material is reduced, especially when the number of laminated layers increases or when the layer thickness becomes thinner, resulting in less deterioration of magnetic head characteristics. Become.

Further, in the present invention, the interlayer insulating material or the gap material,
By using a material mainly composed of SiO2/A 1203, in which the crystal structures of both mullite and cristobalite coexist, the adhesion of magnetic material components in the tape can be improved while the tape is running under a wide range of environments in which it is practically used. is small (
Therefore, stable head output can be obtained and a highly reliable magnetic head can be supplied.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a tape sliding surface of a magnetic head in an embodiment of the present invention, and FIG. 2 is a side view thereof. 1.1゛...Substrate, 2a, 2a'...Amorphous alloy, 3a, 3a'...Insulating material, 4.4゛...
Adhesive glass layer, 5.5°...substrate, 6... winding window, 7... adhesive glass, 8... gap.

Claims (2)

[Claims] (1) In a magnetic head made of a multilayered magnetic material,
A magnetic head characterized in that the interlayer insulating material of the multilayer structure contains oxides of aluminum and silicon as main components, and the oxides of aluminum and silicon simultaneously contain crystal phases of both cristobalite and mullite. (2) The magnetic head according to claim 1, wherein the multilayered magnetic material is made of an amorphous alloy, a sendust alloy, or a permalloy alloy.