JPS59207608A - High permeability magnetic thin film - Google Patents

Abstract

PURPOSE:To obtain a high permeability magnetic thin film by forming a Co-Fe- Si alloy magnetic thin film by sputtering method or the like. CONSTITUTION:A Co-Fe-Si alloy magnetic thin film in an optional shape by sputtering method or evaporation method. At that time, a magnetic thin film which has low magnetostriction and high saturated magnetic flux density can be obtained by choosing the alloy composition of 13-22wt% of Co, 9-15wt% of Si and remainder of Fe. Moreover, corrosion resistance can be improved without deteriorating the magnetic characteristics by adding 1-7wt% of Cr, Ni, Mo, Rh and Ru.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic core material, and particularly to a magnetic film with high saturation magnetic flux density and high magnetic permeability, which is suitable for a magnetic head for high-density magnetic recording.

[Background of the invention]

As the density of magnetic recording has increased, magnetic tapes with high coercive force have come to be used as recording media. Therefore, magnetic head materials for recording and reproducing on these tapes have to have high saturation magnetic flux density and high permeability, which surpass the characteristics of conventional materials. There is a strong desire to develop soft magnetic materials with high magnetic properties. Conventionally, Sendust and Fe6.5%Si1 amorphous magnetic materials have been considered as candidate materials, but Sendust has a saturation magnetic flux density of at most 10 kGL and is an amorphous magnetic material with high magnetic permeability. However, when the saturation magnetic flux density exceeds 13 kG, the thermal stability becomes extremely poor. On the other hand, F of zero magnetostriction
The 86.5% Si crystalline material has a high B8 value of 19 kG, but its corrosion resistance is extremely poor. When the corrosion resistance is improved by adding Cr, platinum elements, etc., the saturation magnetic flux density decreases to 10 kG. There were problems such as deterioration of the soft magnetic properties.

Furthermore, it has been known that a zero magnetostriction composition has been found in the conventional pe-Co-8i ternary alloy, and that high magnetic permeability can be obtained. However, these alloy compositions are extremely hard and brittle, making processing extremely difficult and unsuitable for practical use. Recently, however, it has become possible to ultra-rapidly cool the molten metal into a thin strip using the whole-piece roll method or multi-roll method, and thin strips of these alloys have also been produced, but the processability is still not practical. This is insufficient.

[Purpose of the invention]

An object of the present invention is to provide a high permeability magnetic thin film having good corrosion resistance, extremely low magnetostriction, and a saturation magnetic flux density of 14 kG or more, as a magnetic head material optimal for high coercive force recording media.

[Summary of the Invention] The structure of the present invention for achieving the above object is to produce Co-F with low magnetostriction using either a sputtering method or a vapor deposition method.
An e-Si alloy magnetic thin film is produced in any shape, and furthermore, other magnetic thin films such as Co, permalloy, etc. or S j (h
By producing a laminated magnetic thin film in which non-magnetic thin films such as +k120s are alternately laminated, these magnetic thin films are used as a magnetic core.

Here, in order to make the magnetostriction λB, 1λg K5X10-', and the saturation magnetic flux density, Bs>14kG, the alloy composition must be 13 to 22% CO, 9 to 15% Si, and the balance must be essentially PE. , further Cr1Ni, MO, Rh
By adding 7% or less of Ruff1 by weight, corrosion resistance is further improved without deteriorating magnetic properties.
It is possible to improve soft magnetic properties by reducing magnetostriction.

Furthermore, by producing the laminated magnetic film of the present invention, it is possible to reduce eddy current loss in a high frequency band and obtain high magnetic permeability up to a high frequency band.

The present invention will be explained in detail below using examples.

[Embodiments of the invention]

Example 1 A magnetic film was formed using an Il' sputtering device, and a sputtered film with a predetermined alloy composition was prepared using a target to which a 150-diameter PE inner disk sm + φ disks of other elements were attached. It was made under the following conditions.

High frequency power density...2.8w/cr/l argon pressure...2×1O-2TOrr substrate temperature...
...350C Distance between electrodes ...25m+ Film thickness ...about 1.5μm A non-magnetic glass or ceramic substrate was selected as the substrate. Table 1 shows the magnetic properties of the single layer film obtained as a result.

Table 1 Example 2 For forming a laminated magnetic film, SfOg or C is used in the intermediate layer film.
The main magnetic material film (76% Fe 1
4%Co 10%S i ) No 4 film thickness 0.1μm
15 layers were laminated, and the total film thickness was about 1.5 μm. The conditions for producing the intermediate layer film are shown below.

High frequency power density...0.5W/CW1 Argon pressure...5 X 10-"f'orr Substrate temperature...250C Distance between electrodes...50m Membrane Thickness: 30 people The magnetic properties of the resulting laminated magnetic film are as follows: When 5ins is used as the intermediate layer, coercive force Hc = 1.0IO10, initial permeability μt (5MH2) = 1800, On the other hand, when Co film is used as the intermediate layer, coercive force Hc = 0.50., μth, (5MH
2)=2000.

Embodiment 3 FIG. 1 is a perspective view of a magnetic head formed using the present invention. The laminated magnetic film described in Example 2 is formed on a non-magnetic substrate such as non-magnetic ferrite, and then processed into a predetermined shape as shown in FIG. 1 so that the gap-forming surfaces face each other. A VTR magnetic head was fabricated using the same method, and its head characteristics were evaluated. 1 is a gap, 2 is a coil winding window, 3 is a laminated magnetic film, and 4 is a nonmagnetic substrate. The gap length of the prototype head was approximately 0.3 μm1
The core thickness was 150 μm and the track width was 20 μm. When combined with a high coercivity metal tape, the self-recording/reproducing output was improved by more than 10 to 12 dB compared to the current combination of oxide tape and M n -7,n ferrite head.

Example 4 Using the magnetic thin film produced in Example 1 above, corrosion resistance was examined by a high temperature humidification test (humidity 90%, temperature 60C). As a result, sputtered films with these alloy compositions showed high corrosion resistance with almost no oxidation even after a 200 hour corrosion resistance test.

〔Effect of the invention〕

As is clear from the above description, by using the high permeability magnetic thin film of the present invention, a magnetic head with high saturation magnetic flux density and excellent corrosion resistance can be provided, and the performance of the high coercive force tape can be fully brought out. I can do it.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a magnetic head manufactured using the laminated magnetic film of the present invention. DESCRIPTION OF SYMBOLS 1... Gap, 2... Coil winding window, 3... Laminated magnetic film, 4... Nonmagnetic substrate. Agent Patent Attorney Akio Takahashi

Claims (1)

[Claims] 1. The thin film has a composition consisting of 13 to 22 parts of CO, 9 to 15 parts of Si, and the balance is Fe in terms of weight percentage, and is produced by either a sputtering method or a vapor deposition method. High permeability magnetic thin film. 2.% High magnetic permeability characterized by adding 1 to 7 ts of at least one element selected from Cr, Ni + Mol Rh, and RuO to the alloy composition according to claim 1 in terms of weight percentage. magnetic thin film. 3. A high permeability magnetic thin film, characterized in that the magnetic film according to claim 1 is laminated with another magnetic film or a non-magnetic film interposed therebetween. 4. A high permeability magnetic thin film, characterized in that the high permeability magnetic thin film according to claims 1 and 2 is used as a magnetic core.