KR960004664B1 - Soft-magnetic thin film alloy for magnetic head and the manufacturing method thereof - Google Patents

Abstract

The soft magnetic thin film alloy for magnetic head comprises FexHfyCzNvOw, where x is 71-86; y is 5.5-10.5; z is 1-13; v is 1-13; w is 0-3; z+v+w are 7.5-18.5; x+y+z+v+w = 100. The alloy has high satd. magnetic flux density, high magnetic permeability, and high thermal durability in MHz band.

Description

Iron-based soft magnetic thin film alloy for magnetic head and its manufacturing method

1 is a graph showing the change in coercive force (Hc) according to the composition of the Fe-Hf-C-B-based alloy of the present invention.

2 is a graph showing a change in the effective permeability (μ _eff ) according to the composition of the Fe-Hf-CN-based alloy of the present invention.

3 is a graph showing a change in saturation magnetic flux density (Bs) according to the composition of the Fe-Hf-C-N-based alloy of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron-based soft magnetic thin film material based on a binary composition of Fe-Hf. In particular, Fe-Hf- having excellent soft magnetic properties exhibiting high saturation magnetic flux density, high permeability, and heat resistance in the high frequency region of the MHz band. The present invention relates to an iron-based soft magnetic thin film alloy for CN-based and Fe-Hf-CNO-based magnetic heads.

In recent years, in the field of magnetic recording and reproducing apparatuses such as audio tape recorders and VTRs, researches for increasing the density and quality of recording signals have been actively conducted.

As a means of increasing the recording density, high-magnetization of the recording medium and short wavelength recording have been promoted. In order to cope with the high recording density, magnetic head materials have high saturation magnetic flux density and short wavelength recording and faithful recording signal reproduction. High permeability in the high frequency range of the MHz frequency band is essential.

In addition, during the head manufacturing process, it is necessary to firmly bond the magnetic head gap part with adhesive glass in order to secure the reliability of the head. The problem is that the adhesive glass with high adhesive strength has a high melting point and thus soft magnetic properties for magnetic head. The alloy requires thermal stability and high heat resistance temperature that does not cause soft magnetic deterioration even at high temperatures.

Conventional soft magnetic materials for magnetic heads include Fe-Al-Si-based sendast alloys, Ni-Fe-based permalloy alloys, Co-based amorphous alloys, and the like.

Among these conventional soft magnetic materials, the sendast alloy and the permalloy alloy have a high internal stress of the film and easy to grow crystal grains, making it difficult to produce thin films having good soft magnetic properties. Not suitable for records

In addition, Co-based amorphous alloys have the advantages of not only good soft magnetic properties but also a thin film having a saturation magnetic flux density of about 13 kG, but are crystallized at about 450 ° C. to deteriorate soft magnetic properties. Application of adhesive glass is difficult in the manufacture of magnetic heads with sufficient bonding strength.

On the other hand, iron nitride is known as a recently developed soft magnetic material, and this alloy is generally formed in a thin film form by ion beam deposition or reactive sputtering by targeting iron in a nitrogen-containing atmosphere. In some cases.

However, such a soft magnetic thin film has a problem in that the coercive force rapidly increases by heat treatment or heating, resulting in insufficient thermal stability.

In Japanese Patent Application Laid-Open No. 2-275605, Fe-XN (X = Zr, Hf, Ti, etc.) and Japanese Patent Application Laid-Open No. 3-20444 include Fe-MC (M = Ti, Zr). , Hf, etc.) is described as exhibiting good soft magnetic properties.

However, in the case of the Fe-X-N-based thin film, the saturation magnetic flux density in the composition region exhibiting high permeability at high frequency is relatively low as about 15 kG, and the soft magnetic properties deteriorate at 550 ° C. or higher, resulting in insufficient thermal stability.

In addition, the Fe-MC-based thin film has an advantage that the heat resistance temperature is high as high as about 650 ℃ and the saturation magnetic flux density is better than the Fe-XN type as high as 16kG, but this also has a good softening in the composition region having a superfine magnetic flux density exceeding 17kG. Magnetic properties are not obtained, and the magnetic permeability at high frequencies is lower than that of Fe-XN-based or Co-based amorphous alloys.

Accordingly, the present invention is based on the Fe-Hf binary alloy as a new soft magnetic material for solving the problems of the conventional soft magnetic thin film material for the magnetic head, by combining C, N and O with each other. It is an object of the present invention to provide an iron-based soft magnetic thin film alloy having excellent heat resistance and high saturation magnetic flux density and high permeability in the high frequency region of the MHz band by alloying.

The composition of the iron-based soft magnetic thin film alloy for the magnetic head to achieve the object of the present invention is as follows, the internal structure is made of ultra-fine crystals.

Fe _x Hf _y C _z N _v O _w

Where x, y, z, v, w are atomic%,

71≤x≤86

5.5≤y≤10.5

1≤z≤13

1≤v≤13

0≤w≤3

7.5≤z + v + w≤18.5

(Where x + y + z + v + w = 100)

If it is out of the above formula and component limitation range, it is impossible to obtain an iron-based soft magnetic thin film alloy having both high saturation magnetic flux density, high permeability, and heat resistance. This is because the required ultrafine crystals are not formed.

Fe-Hf-C-N-based and Fe-Hf-C-N-O-based soft magnetic and thin film alloy of the present invention is obtained through the following manufacturing process.

The soft magnetic thin film alloy of the present invention is manufactured by a sputtering method or other physical vapor deposition method, and the manufacturing process by the sputtering method will be described as follows.

Placing Hf, nitrides of Hf, oxides of Hf, carbides of Hf and carbides of C on targets such as pure iron, Fe-Hf alloys or Fe-Hf-C alloys in the sputtering apparatus, or Fe-Hf-CN or Fe- A thin film is formed by sputtering a target, such as an Hf-CNO alloy, in an atmosphere containing C, N, or O in an impurity sputtering gas or a sputtering gas.

Thus, the Fe-Hf-CN-based and Fe-Hf-CNO-based soft magnetic thin film alloys obtained by the sputtering method are subjected to a heat treatment in a vacuum or an atmosphere containing Ar or N ₂ as a subsequent heat treatment process or heat at the time of supplying the magnetic head. The manufacturing process is completed by heat-treating by the process of supplying (S).

The iron-based soft magnetic thin film alloy of the present invention obtained through such a manufacturing process has high magnetic flux density and high permeability in the high frequency region of the MHz band, exhibiting high performance by high recording density and faithful recording and reproducing excellent nitrile properties. Because of its excellent soft magnetic properties, it is suitable for thin film magnetic heads and MIG heads.

The characteristics and manufacturing method of the iron-based soft magnetic thin film alloy for the magnetic head of the present invention will be more clearly understood through the following examples.

Example 1

The 1-micrometer-thick Fe-Hf-CN thin film of various compositions was produced with the high frequency bipolar magnetron sputtering apparatus. In order to change the composition of the thin film, small pieces of Hf and C are arranged in a pinhole on the Fe target, and the number of each piece is changed, and reactive sputtering is performed by changing the flow rate ratio of each gas in the mixed gas atmosphere of Ar gas and N ₂ gas. It was. At this time, the input power was 300W, the total pressure of the mixed gas was 1mtorr. Magnetic properties of the thin film manufactured by this method are shown in Table 1 below. The change in the coercive force (Hc) according to the composition of the Fe-Hf-CN based ultrafine thin film alloy is shown in FIG. 1, the change in the effective permeability (μ _eff ) is shown in FIG. 2, and the saturation magnetic flux density (Bs) The changes are shown in FIG. 3 respectively. The coercive force and the saturation magnetic flux density in Table 1, 1 and 3 are measured by a vibratory sample magnetic flux meter (VSM) and the effective permeability of FIG. 2 was measured by an impedance analyzer using a ferrite core method.

Example 2

Fe-Hf-CNO thin films of various compositions were prepared to have a thickness of 1 μm by a high frequency bipolar magnetron sputtering apparatus. In order to change the composition of the thin film, Hf and C pieces were placed in a hole shape on the Fe target, and the number of pieces was changed, and the flow rate ratio of each gas was changed in the mixed gas atmosphere of Ar gas, N ₂ gas, and O ₂ gas. Reactive sputtering was performed. At this time, the input power was 300W, the total pressure of the mixed gas was 1mtorr. Magnetic properties of the thin film manufactured by this method are shown in Table 2 below.

According to the results presented in Examples 1 and 2, the Fe-Hf-CN system having a high saturation magnetic flux density and a high transmittance of saturation magnetic flux density of 17 kG or more and an effective permeability of 5,000 or more at 1 MHz and a high heat resistance temperature of 650 ° C. and It can be seen that the Fe-Hf-CNO-based soft magnetic thin film alloy is obtained.

Comparative Example 1

A Fe-Hf-N thin film was produced by high frequency sputtering in an argon gas atmosphere containing nitrogen using a Fe-Hf alloy target (Japanese Patent Laid-Open No. 2-275605).

Magnetic properties of the thin film are shown in Table 3 below.

Comparative Example 2

Fe-Nb-N-O thin films were prepared by RF sputtering using an Fe-Nb alloy target in an argon gas atmosphere containing nitrogen gas and oxygen gas (Japanese Patent Laid-Open No. 3-232206).

Magnetic properties of the thin film are shown in Table 4 below.

Comparative Example 3

A small piece of Hf and C was placed on the Fe target, or Rf was placed on the Fe target, and sputtered in an Ar + CH ₄ atmosphere to prepare a Fe-Hf-C thin film. (Japanese Patent Laid-Open No. 3-20444) The magnetic properties are shown in Table 5 below.

Through the above examples and comparative examples, it can be seen that the iron-based ultrafine crystalline soft magnetic thin film alloy prepared by the present invention has superior magnetic properties and heat resistance as compared with the basic soft magnetic thin film alloy.

Although the present invention has been described in detail by the above examples, the present invention is not to be construed as being limited by these examples, and the composition and manufacturing method of the thin film material may be varied within the scope of the present invention described in the claims. It can be modified and changed.

Claims (2)

The composition formula Fe _x Hf _y C _z N _v O _w Where x, y, z, v, w are atomic%, 71≤x≤86 5.5≤y≤10.5 1≤z≤13 1≤v≤13 0≤w≤3 7.5≤z + v + w≤18.5 (Where x + y + z + v + w = 100) Iron-based soft magnetic thin film alloy for magnetic heads, characterized in that consisting of. Placing Hf, Hf nitride, Hf oxide, Hf carbide, and C fragment on targets such as pure iron, Fe-Hf alloy, Fe-HF-C alloy, or Fe-Hf-CN or Fe-Hf-CNO alloy The target is sputtered in an inert sputtering gas or in an atmosphere containing C, N or O in the sputtering gas to form a thin film, and then heat-treated in vacuum or in an Ar and N ₂ atmosphere to produce an iron-based ultrafine soft magnetic thin film alloy. A method of manufacturing an iron-based soft magnetic thin film alloy for magnetic heads, characterized in that.