JPH056822A - Soft magnetic film - Google Patents

Abstract

PURPOSE:To obtain a high-saturation magnetic flux density, satisfactory soft magnetic properties and heat resistance by constituting the title film from predetermined elements and by observing a scattering diffraction through X-ray diffractometry using Co-Kalpha radiation. CONSTITUTION:While alloys containing the components of Co85Zr15, Fe85Al15 and Fe90Si10 are used as targets and the mixed gas of Ar and N2 gas is introduced into a sputter, a film formation is conducted by RF mgnetron sputtering process. Then, while an alloy containing the components of Fe85Hf15 is used as target and the mixed gas of Ar and N2 gas is introduced into the sputter, the film formation is conducted by DC magntron sputtering process. Obtained films containing the components of Co90Zr9N1, Co80Zr8N12, Fe80Hf10, Fe79Al13N8 and Fe81Si8N11 are subjected to a heat treatment in a vacuum at 500 deg.C for 1 hour and to X-ray diffractometry using Co-Kalpha radiation and to measurements of coersive force and saturation magnetic flux density. The Co amorphous film and Fe-based alloy film are known to differ in scattering strength according to a film in a small angle scattering region where a scattering angle is 2-6 degrees.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft magnetic thin film suitable as a core material for a composite type magnetic head or a thin film type magnetic head.

[0002]

2. Description of the Related Art For example, in a magnetic recording / reproducing apparatus such as a VTR (video tape recorder), the density of recording signals has been increased in order to improve the image quality and the like. Development of high coercive force media such as so-called vapor-deposited tape in which powder of ferromagnetic metal such as Co and Ni is used, so-called metal tape or ferromagnetic metal material is directly deposited on the base film by a method such as vapor deposition. ing.

By the way, as the coercive force of the magnetic recording medium is increased, the saturation magnetic flux density is also required to be increased as a magnetic head used for recording and reproduction. However, it is difficult for a magnetic head made of a ferrite material that has been conventionally used to sufficiently meet such a demand for high saturation magnetic flux density.

Under such circumstances, therefore, the magnetic core constituting the magnetic head has a composite structure of ferrite, ceramics, etc. and a soft magnetic film having a high saturation magnetic flux density, and the soft magnetic films are butted to form a magnetic gap. There has been developed a composite type magnetic head configured as described above, a thin film magnetic head in which each magnetic core, a coil, and the like are formed by a thin film technique, and these are formed into a multilayer structure with an insulating film interposed therebetween.

As the soft magnetic material used for the above-mentioned composite magnetic head or thin film magnetic head, for example, Fe-Al-S is used.
Known are i alloys, so-called sendust alloys, amorphous soft magnetic films of Co—Nb—Zr, and the like.

However, in the Fe-Al-Si alloy, the saturation magnetic flux density is 10 kGauss in the composition that gives the most soft magnetic characteristics, which is sufficiently satisfactory as the core material of the magnetic head used for the high coercive force medium. It can not be said. Further, in the amorphous alloy, the crystallization temperature is low in the composition that can obtain the saturation magnetic flux density of 10 k Gauss or more, and the soft magnetic characteristics are impaired in the glass fusion performed in the manufacturing process of the magnetic head.

Therefore, as a soft magnetic thin film that simultaneously achieves a high saturation magnetic flux density, good soft magnetic characteristics, and heat resistance, a Co-based amorphous film or a Fe-based alloy film in which nitrogen is periodically added is soft magnetic. The thin film is disclosed in JP-A-63-254708,
It is reported in Japanese Patent Laid-Open No. 1-209707.

[0008]

However, in the soft magnetic thin film containing nitrogen as described above, nitrogen is periodically contained at a cycle of 100 nm or less in order to obtain good soft magnetic characteristics. In order to form a soft magnetic thin film to which nitrogen is added periodically as described above, a complicated operation of periodically changing the partial pressure of nitrogen in the sputtering atmosphere by using the reactive sputtering method is required. For this reason,
There is a problem that it takes time and labor to manufacture, and sufficient mass productivity cannot be obtained as a magnetic head core material.

Therefore, the present invention has been proposed in view of such conventional circumstances, and has a high saturation magnetic flux density, is excellent in soft magnetic characteristics and heat resistance, and is capable of obtaining sufficient mass productivity. The purpose is to provide.

[0010]

When an X-ray diffraction measurement is performed on a Co-based amorphous film, a Fe-based alloy film, etc., it has been found that the scattering intensity in the range where the scattering angle is small greatly differs depending on the film. That is, this suggests that the scattering intensity in the range where the scattering angle is small is one index for judging the characteristics of the film. From such a viewpoint, the inventors of the present invention have conducted extensive studies on the magnetic characteristics of the film, and as a result, among the magnetic thin films formed of a specific element, the scattering angle is 2 to 6 when the X-ray diffraction measurement is performed. We have found that good soft magnetic properties and excellent heat resistance can be obtained for those whose scattering diffraction is observed in the small angle scattering region.

Based on such knowledge, the soft magnetic film of the present invention has at least one selected from Co, Fe, Ni and Mn.
Seed and Zr, Hf, Ta, Nb, Y, W, Mo, Ti, C
r, V, Cu, La, Nd, Sm, Ce, Pr, Gd,
Dy, Al, Si, Ge, Ga, Pd, Ru, Re, S
X-ray diffraction measurement using CoKα radiation, which consists of at least one selected from n and at least one selected from N, C, O, B and P, and has a scattering angle in the range of 2 to 6 degrees. It is characterized by the fact that diffraction is observed.

In the present invention, in order to obtain good soft magnetic characteristics and heat resistance, it is composed of a predetermined element and CoK
In X-ray diffraction measurement using α radiation, it is important that scattering diffraction is observed in the range of 2 to 6 degrees. That is, from the scattering angle 2θ observed by the X-ray diffraction measurement, the scattering grating plane spacing d can be obtained by using the equation 1.

[0013]

[Formula 1] Since the wavelength λ of CoKα radiation is 1.79026Å, when scattering diffraction is observed in the scattering angle range of 2 ° to 6 °, the scattering lattice plane spacing d is 1.7 nm to 5 nm according to Equation 1.
nm. That is, when the predetermined element has a crystal structure with such a scattering lattice plane spacing, good soft magnetic characteristics and heat resistance can be achieved.

The soft magnetic film can be obtained by adjusting the sputtering conditions and the target composition by using a so-called vapor phase plating technique such as sputtering. Here, as the target, an alloy target made of a predetermined element having a desired composition may be used, or a soft magnetic film formed by adjusting the area and applied output of each predetermined element as a target. The composition of the film may be controlled. In particular, when an alloy target is used, the composition of the soft magnetic film is almost uniquely determined by the composition of the target, so that there is no error in the composition for each sputtering, which is advantageous for mass production. Also,
To add nitrogen and oxygen, introduce nitrogen gas or oxygen gas into the sputtering atmosphere, and to add carbon,
A hydrocarbon gas such as methane or acetylene may be introduced into the sputtering atmosphere.

[0015]

[Function] The soft magnetic film, which is composed of a specified element and whose scattering angle is observed in the range of 2 to 6 degrees by X-ray diffraction measurement using CoKα radiation (wavelength 1.79026Å), has a high saturation. It has a magnetic flux density, as well as excellent soft magnetic properties and heat resistance. The reason for this is not clear, but CoKα
In X-ray diffraction measurement using radiation, when scattering diffraction is observed in the range of 2 to 6 degrees, the scattering lattice plane spacing d is 1.7 nm to 5 nm, and the predetermined element is By taking the crystal structure of the scattering lattice plane spacing,
It is considered that good magnetic properties and heat resistance can be achieved.

In the soft magnetic film of the present invention, the crystal structure is important as described above, and the composition does not have to be as strict as that of the nitrogen modulation film (for example, an element other than the predetermined element is 1 atomic% by weight). Even if it is contained within the range, the characteristics do not deteriorate.) Therefore, the stability of the characteristics is high and the reliability as a core material can be obtained. Further, a soft magnetic film having such a scattering lattice spacing is formed by a sputtering method. In this case, the sputtering conditions and the target composition are adjusted first, and the conditions are continued until the desired film thickness is obtained. It suffices to carry out sputtering by means of a sputtering method, and there is no need to periodically change the sputtering atmosphere as with the nitrogen modulation film. Therefore,
It does not require labor and time for film formation and is excellent in mass productivity.

[0017]

EXAMPLES Preferred examples of the present invention will be described based on experimental results.

First, Co ₈₅ Zr ₁₅ , Fe ₈₅ Al ₁₅ , Fe
_Using an alloy having a composition of ₉₀ Si ₁₀ (diameter 100 mm) as a target, film formation was performed by the RF magnetron sputtering method while introducing a mixed gas of Ar and N ₂ gas during sputtering. The sputtering conditions are shown below. Sputtering conditions Ultimate vacuum 2 × 10 ⁻⁴ Pa Ar gas pressure 0.1 Pa Input power 300 W The film obtained at this time had a thickness of 3 μm and a nitrogen composition ratio of 0.2 atomic% to 20 atomic%. ..

Next, using an alloy having a composition of Fe ₈₅ Hf ₁₅ (diameter 100 mm) as a target, a film was formed by the DC magnetron sputtering method while introducing a mixed gas of Ar and N ₂ gas during sputtering. .. The sputtering conditions are shown below. Sputtering conditions Ultimate vacuum 2 × 10 ⁻⁴ Pa Ar gas pressure 0.5 Pa Input power 300 W The film obtained at this time had a thickness of 3 μm and a nitrogen composition ratio of 0.2 atomic% to 20 atomic%. ..

Co ₉₀ Zr ₉ N obtained as described above
₁ , Co ₈₀ Zr ₈ N ₁₂ , Fe ₈₀ Hf ₁₀ N ₁₀ , Fe ₇₉ Al
Regarding a film having a composition of ₁₃ N ₈ and Fe ₈₁ Si ₈ N ₁₁ ,
Heat treatment was performed at 500 ° C. for 1 hour in vacuum, and X-ray diffraction measurement, coercive force, and saturation magnetic flux density were measured. FIG. 1 shows the X-ray diffraction pattern of each film, and Table 1 shows the small-angle scattering intensity, saturation magnetic flux density, and coercive force of each film.

The X-ray diffraction was measured at a wavelength of 1.790.
Performed by the θ-2θ method with 26 K of CoKα radiation. The small-angle scattering intensity was evaluated by summing the intensities of the scattering peaks observed when the scattering angle was 2 to 6 degrees. The coercive force Hc was measured by a BH loop tracer, and the saturation magnetic flux density was measured by a sample vibrating magnetometer.

[0022]

[Table 1]

As can be seen from FIG. 1, a Co type amorphous film,
In the Fe-based alloy film, there is almost no difference in the scattering intensity in the high-angle scattering region where the scattering angle is 30 ° to 80 °, but the scattering intensity differs depending on the film in the small-angle scattering region where the scattering angle is 2 ° to 6 °. .. That is, this suggests that the scattering intensity of the small-angle scattering region is an index for judging the characteristics of the film.

In Table 1, the magnetic properties are examined using the scattering intensity in the small angle scattering region as an index. A film having a low small angle scattering intensity has a high coercive force after heat treatment, and sufficient soft magnetic properties cannot be obtained. However, a film having a large small angle scattering intensity has a high saturation magnetic flux density and a low coercive force even after heat treatment. From this fact, the small-angle scattering intensity measured using CoKα radiation in a film made of a predetermined element is closely related to its magnetic properties, and a good soft magnetic property is obtained in a composition having a high small-angle scattering intensity. It was found that it exhibits properties and heat resistance.

Next, in order to further secure the relationship between the scattering intensity and the magnetic characteristics in the small angle scattering region, CoZ
rN, CoNbN, CoHfN, CoTaN and Co
Films made of YN were formed with various compositions, and the small angle scattering intensity and the coercive force after heat treatment at 500 ° C. were measured. The result is shown in FIG.

As is apparent from FIG. 2, a film having a small peak intensity in the small angle scattering region has a high coercive force, and effective soft magnetic characteristics are not obtained, but a film having a large peak intensity has a coercive force. Small and good soft magnetic properties can be obtained. Therefore, also from this, it is found that the small-angle scattering intensity is an index for obtaining a film having excellent soft magnetic properties, and in order to obtain a film having good soft magnetic properties, among films made of a predetermined element, , X-ray diffraction measurement using CoKα radiation, it was shown that the one with large peak intensity in the small angle scattering region should be selected.

The peak intensity in the small-angle scattering region of the film depends substantially on the sputtering conditions and target composition at the time of forming the film. Therefore, in order to obtain a film having a large peak intensity in the small-angle scattering region, the sputtering condition and the target are first obtained. The composition may be adjusted, and sputtering may be continuously performed under the conditions until the desired film thickness is obtained. Therefore, it does not require time and labor such as changing the film forming conditions on the way, has excellent stability of characteristics, and is advantageous in mass production.

[0028]

As is clear from the above description, the soft magnetic film of the present invention is made of a predetermined element and has a scattering angle 2θ of 2 in X-ray diffraction measurement using CoKα radiation.
Since scattering diffraction is observed in the range of 6 to 6 degrees, it is possible to obtain high saturation magnetic flux density, good soft magnetic characteristics, and heat resistance. Moreover, since the soft magnetic film does not need to change the sputtering atmosphere or the like during the film formation by the sputtering method, it does not require much labor and time for film formation, and is suitable for mass production and has stable characteristics. Is also excellent
High reliability is obtained as a core material.

Therefore, according to the present invention, a soft magnetic film which can be sufficiently applied as a core material of a head for a high coercive force medium such as a metal in-gap head and which is highly practical in terms of productivity and stability of characteristics. It is possible to obtain.

[Brief description of drawings]

FIG. 1 is a diagram of C-based amorphous film and Fe-based alloy film.
It shows a scattering pattern when an X-ray diffraction measurement is performed using oKα radiation.

FIG. 2 is a characteristic diagram showing a relationship between a scattering peak intensity in a small angle scattering region and a coercive force after heat treatment in each composition system.

Claims (1)

Claims: 1. At least one selected from Co, Fe, Ni, Mn and Zr, Hf, Ta, Nb, Y, W, M.
o, Ti, Cr, V, Cu, La, Nd, Sm, Ce,
Pr, Gd, Dy, Al, Si, Ge, Ga, Pd, R
at least one selected from u, Re, Sn and N, C,
A soft magnetic material comprising at least one selected from O, B, and P, and scattering diffraction is observed in the range of 2 to 6 degrees in X-ray diffraction measurement using CoKα radiation. film.