JPH05239601A - Soft magnetic alloy thin film and its manufacture - Google Patents

Abstract

PURPOSE:To form a soft magnetic alloy thin film excellent in saturation mag netic flux density and coercive force by using an Fe-Al-Si-Co 'Sendust (R)'alloy as a target material and executing sputtering in an atmosphere of an N2 gas-contg. Ar gas. CONSTITUTION:An Fe-Al-Si-Co 'Sendust (R)' alloy is used as a target material, and reaction sputtering is executed in an atmosphere formed by mixing an N gas having 2.5 to 3.5% partial pressure into an Ar gas to form an Fe-Al-Si- Co-N alloy thin film on a film forming substrate heated to about 200 to 300 deg.C. In this way, the objective soft magnetic alloy thin film constituted of 4.0 to 8.0% Al, 6.0 to 12.0% Si, 2.0 to 4.0% Co and 1.0 to 1.7% N, and the balance substantial Fe and having about >=1200G saturation magnetic flux density and about <=0.20e coercive force can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft magnetic alloy thin film and a method for producing the same, and more particularly to a soft magnetic alloy thin film having excellent saturation magnetic flux density and coercive force used for a magnetic head core material and a method for producing the same. ..

[0002]

2. Description of the Related Art In recent years, the magnetic characteristics of a magnetic head core material, which is the most important component of a magnetic recording / reproducing apparatus, have been required to be strict as the density of magnetic tape increases.

That is, it has a high saturation magnetic flux density, a low coercive force, excellent wear resistance and corrosion resistance, good magnetic characteristics in a high frequency range, and easy precision machining. Various characteristics such as stable magnetic characteristics against temperature are required.

Ferrite or permalloy-based alloys have been used as magnetic head core materials conventionally used to meet these demands, but these materials have advantages and disadvantages.

For example, ferrite has extremely high electric resistance and high hardness, and has excellent high-frequency characteristics, wear resistance and corrosion resistance, but on the other hand, it has a low saturation magnetic flux density and is used in a magnetic head. There is a problem in workability because it is easy to generate noise and mechanically brittle.

On the other hand, although the permalloy type alloy has a relatively high saturation magnetic flux density, it cannot be said to be a sufficient value for coping with the high density of the magnetic tape, and further improvement by various additive elements is performed. However, the abrasion resistance is not sufficient.

For these reasons, sendust type alloys have recently attracted attention as magnetic head materials. That is, the sendust-based alloy has the characteristics that it has an extremely high saturation magnetic flux density containing Fe, Si, and Al as the main components and that it also has good wear resistance, and is a highly promising alloy as a magnetic head core material. ..

[0008]

However, the sendust-based alloy contains a large amount of Si and Al and is extremely fragile and difficult to process. In addition, it is difficult to process the magnetic recording medium (magnetic tape) of high coercive force these days. There is a demand for improvement in magnetic characteristics such that the saturation magnetic flux density is further increased and the coercive force is lowered.

[0009]

The present invention has been made to solve the above-mentioned problems. Al; 4.0-8.0%,
Si; 6.0-12.0%, Co; 2.0-4.0%, N; 1.0-1.7
%, A soft magnetic alloy thin film consisting essentially of Fe, and a Fe-Al-Si-Co-based sendust alloy as the target material of the sputtering apparatus, with a partial pressure of 2.5 to 3.5% for Ar gas.
Reactive sputtering is performed in an atmosphere mixed with N gas, and Fe- is deposited on the film-forming substrate heated to about 200-300 ℃.
The present invention provides a method for producing a soft magnetic alloy thin film, which comprises forming an Al-Si-Co-N alloy thin film.

[0010]

EXAMPLE The present invention is effective for improving the magnetic properties of Co, and effective for improving the coercive force and the saturation magnetic flux density, with respect to the general sendust type alloy composed of Fe-Al-Si. As a result of studying the inclusion of N and Fe-Al-Si
To a Sendust-based alloy consisting of Co; 2.0 to 4.0%, and N;
Novel Fe-Al-with a composition containing 1.0 to 1.7%
We were able to find a Si-Co-N soft magnetic alloy thin film.

Here, the sendust type alloy composed of Fe-Al-Si is a general sendust type alloy, but in order to maintain excellent magnetic properties, at least the basic component Al,
Si must contain Al; 4.0% and Si; 6.0% or more. However, if too much is contained, the magnetic properties will start to deteriorate, so the content should be Al; 8.0% and Si; 12.0% or less. Is desirable.

Furthermore, the fact that Co is 2.0 to 4.0% means that Co is an effective element for improving the magnetic properties, and it is necessary to contain Co in an amount of 2.o% or more, but too much. On the contrary, the magnetic characteristics start to deteriorate, so 4.0%
Limited to:

Further, the fact that N is 1.0 to 1.7% means that N
Is an element effective for improving the coercive force and the saturation magnetic flux density, and it is necessary to contain 1.0% or more.However, if too much is contained, the magnetic properties will start to deteriorate.
It was set to 7% or less. The reasons for these limitations will be described later.

Next, the method for producing the Fe-Al-Si-Co-N type alloy thin film of the present invention will be described in detail.

The Fe-Al-Si-Co-N alloy thin film of the present invention is formed by using a vacuum film forming technique such as a sputtering method. As the target material, an alloy in which 2.0 to 4.0% of Co is added to a Sendust-based alloy of Al-Si-Fe is used, and the film formation substrate is heated to about 200 to 300 ° C. This sputtering method is performed by replacing the inside of the chamber of the sputtering device with a mixed gas of Ar gas and N gas in order to react the target material with nitrogen. The partial pressures of these Ar gas and N gas must be accurately controlled by using their respective mass flow controllers.

The sputtering conditions are shown below.

Degree of vacuum 3 × 10 ^-6 Torr or less Substrate temperature 250 ° C. Deposition substrate Crystallized glass gas Ar + N mixed gas Gas pressure 6 mTorr Gas flow mixed gas 20 CCM Film thickness about 3 μm Film deposition rate About 700 nm / min Heat treatment 550 ° C. Hold in vacuum for 1 hour Using the above sputtering conditions, the amount of Co added is 2.0 to
Fe-Al-Si-Co-based alloy with 6.0% change was used as the target, and Fe-Al- with N gas partial pressure was changed to 1-5%.
Si-Co-N alloy thin film (sample N0,1-6) and N gas partial pressure
Fe-Al-Si-Co based alloy thin films (Sample N0,7) made to be 0% were prepared as follows, and measurement was performed on these alloy thin films.

Co addition amount% N gas partial pressure% Thin film composition Sample N0,1 6 1.0 Fe-Al-Si-Co-N series alloy Sample N0,2 5 2.0 Fe-Al-Si-Co-N System alloy Sample N0,3 4 2.5 Fe-Al-Si-Co-N system alloy Sample N0,4 4 3.0 Fe-Al-Si-Co-N system alloy Sample N0,5 3 3.5 Fe- Al-Si-Co-N-based alloy Sample N0,6 2 4.0 Fe-Al-Si-Co-N-based alloy Sample N0,7 8 0 Fe-Al-Si-Co-based alloy Above samples N0,1 to 6 As a result of measuring the coercive force of
When the N gas partial pressure was 2.5 to 3.5%, the coercive force was extremely low, and when it was 4% or more, it was 1 Oe or more, and the soft magnetism was lost.

FIG. 1 is a diagram showing the relationship between the partial pressure of N gas and the coercive force of the samples N0,5. The partial pressure of N gas is 2.5 to 3.5.
It shows the best coercive force in the range of%.

FIG. 2 shows the EPMA analysis results of the samples N0,1 to 7, and it can be seen from the figure that the N content in the alloy film increases in proportion to the increase in the partial pressure of N gas.

From the above measurement results, the partial pressure of N gas under the sputtering conditions is set to 2.5 to 3.5%, the N content in the alloy film is 1.0 to 1.7%, and the Co content is 2.0 to.
It can be seen that good results are obtained for samples N0,3 to 5 with 4.0%.

Further, the above samples N0,3, sample N0,5, sample N
Magnetic properties of 0 and 7 were measured. In the measurement, the saturation magnetic flux density, the coercive force, and the anisotropic magnetic field were measured by VSM, and the magnetic permeability was measured by using the ferrite yoke method.

FIG. 3 is a diagram showing the results of measurement of the magnetic characteristics. From the same figure, it can be seen that the samples N0,
3 and Samples N0 and 5 both show high saturation magnetic flux density and low coercive force, and are superior to the conventional Sendust alloy, Samples N0 and 7.

FIG. 4 is a frequency characteristic diagram of the initial magnetic permeability of the samples N0,3, N0,5 and N0,7, which is a conventional sendust film sample N0,7 (indicated by a solid line in the figure). Sample N, which is a Fe-Al-Si-Co-N alloy thin film with a N gas partial pressure of 2.5% compared to
0 and 3 (indicated by a chain double-dashed line in the figure) show higher magnetic permeability than the conventional sendust film over the entire frequency range. Also,
Even in sample N0,5 (shown by the dotted line in the figure), which is a Fe-Al-Si-Co-N alloy thin film with N gas partial pressure of 3.5%, the magnetic permeability is higher than that of the conventional sendust film in the high frequency range (10 MHz). Is shown.

As described above, Fe-Al-Si-Co- of the present invention
The N-based alloy thin film has magnetic properties superior to those of the conventional sendust film, and is suitable for use in a MIG type magnetic head or a thin film magnetic head.

[0026]

As described above, Al; 4.0-8.0%, S
i; 6.0 to 12.0%, Co; 2.0 to 4.0%, N; 1.0 to 1.7%,
The soft magnetic alloy thin film having the balance substantially Fe was able to improve the magnetic characteristics to a saturation magnetic flux density of 1200 G or more and a coercive force of 0.2 Oe or less as compared with the conventional Sendust-based alloy.

Therefore, the Fe-Al-Si-Co-N of the present invention
The magnetic head using the system alloy thin film can sufficiently cope with the medium of recent high coercive force.

Fe-Al-Si-Co sendust alloy was used as the target material of the sputtering apparatus, and reactive sputtering was performed in an atmosphere in which Ar gas was mixed with N gas having a partial pressure of 2.5 to 3.5%. By providing a method of manufacturing a soft magnetic alloy thin film, which comprises forming an Fe-Al-Si-Co-N alloy thin film on a film-forming substrate heated to about 200 to 300 ° C,
The deposited film of the Fe-Al-Si-Co-N-based alloy can be easily obtained. Further, by heating the film-forming substrate to about 200 to 300 ° C. to perform the reactive sputtering, the adhesion between the film-forming substrate and the Fe-Al-Si-Co-N based alloy thin film can be strengthened. And so on.

[Brief description of drawings]

FIG. 1 is a relationship diagram between a partial pressure of N gas and a coercive force according to the present invention.

FIG. 2 EP of Fe-Al-Si-Co-N alloy thin film of the present invention
It is a MA analysis result.

FIG. 3 is a result of measuring magnetic properties of the Fe-Al-Si-Co-N alloy thin film of the present invention.

FIG. 4 is a frequency characteristic diagram of the initial magnetic permeability of the Fe-Al-Si-Co-N alloy thin film of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01F 1/14

Claims (2)

[Claims] 1. Al: 4.0 to 8.0%, Si; 6.0 to 12.0%, C
o; 2.0-4.0%, N; 1.0-1.7%, the balance is substantially Fe
A soft magnetic alloy thin film made of. 2. Fe- is used as a target material for a sputtering apparatus.
On an Al-Si-Co sendust alloy, reactive sputtering was performed in an atmosphere in which Ar gas was mixed with N gas with a partial pressure of 2.5 to 3.5%, and the film was formed on a substrate heated to about 200 to 300 ° C. A method of manufacturing a soft magnetic alloy thin film, comprising forming an Fe-Al-Si-Co-N based alloy thin film on.