JPH0610848B2 - Laminated magnetic material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminated magnetic material suitable for a magnetic head and the like.

2. Description of the Related Art Conventionally, a laminated magnetic material in which an insulator is sandwiched between magnetic materials has been devised to improve frequency characteristics, and in recent years, the magnetic material itself has been multilayered to improve soft magnetism. Attempts are being made. For example, as an example of the former, as shown in FIG. 2, a 6.5 wt% Fe-Si film 4 having a small magnetostriction constant is formed into a multi-layer film, and a non-magnetic SiO ₂ film thinner than the Fe-Si film 4 is formed between them.
There is one in which the insulating layer 5 is arranged. As an example of the latter, as shown in FIG. 3, extremely thin Ni-Fe of about 30 to 100Å
There is an attempt to improve the magnetic characteristics of the Fe-Si film 4 by interposing the film 6.

Problems to be Solved by the Invention In the above conventional multilayer film, if the thickness of the non-magnetic layer SiO ₂ is increased, the wear resistance as a whole is improved.
i causes uneven wear and deteriorates the soft magnetic characteristics of Fe-Si, and at the same time, the ratio of the Fe-Si film portion to the whole laminated film decreases, and the saturation magnetization of the entire laminated film decreases, which is not desirable. . On the other hand, if the Ni-Fe film, which is a soft magnetic material, is sandwiched between the Fe-Si films, the soft magnetism of the Fe-Si film is hard to be damaged even if the Ni-Fe film is relatively thick, but as a whole, Wear resistance is Ni-F
Since both e and Fe-Si films are low, it has been a problem when these multilayer films are applied to magnetic heads and the like.

It is an object of the present invention to solve the above problems and to realize a magnetic material having both wear resistance and magnetic properties.

Means for Solving Problems A thin film 1 composed mainly of Fe and Si having a magnetostriction constant λ of 1 × 10 ^-5 or less, and an amorphous material having λ of 1 × 10 ^-5 or less and excellent in wear resistance. A thin film 2 made of an alloy or Fe-Si-Al alloy, where t ₁ and t ₂ are film thicknesses of the thin films 1 and 2, respectively, t ₁ and t ₂ <1000Å and t ₁ <2t Alternately laminated as in ₂ to make a multilayer film.

Effect The inventors of the present invention make two kinds of films into a multi-layer, and if one thin film of each of them is made extremely thin, uneven wear between different films becomes small, and the wear as a whole also resists one film. It has been discovered that the improvement can be achieved by using an amorphous alloy or a Fe-Si-Al alloy film having good wear properties. Fe-Si alloy film 1 having a magnetostriction λ of 1 × 10 ⁻⁵ or less is one that has a high saturation magnetization as a whole and exhibits soft magnetism that can be used for magnetic head materials.
Also, a multilayer film including an amorphous alloy film or Fe—Si—Al alloy film 2 having excellent wear resistance with a λ of 1 × 10 ⁻⁵ or less is suitable, and the thickness of each film is as described above. By controlling in this manner, good wear resistance can be obtained.

Example The present invention enables a laminated magnetic material having high saturation magnetization and excellent wear resistance. An outline of the laminated magnetic body of the present invention is shown in FIG. In the figures (a) and (b), 1 is a Fe-Si film of a soft magnetic material whose main component is Fe and Si having a magnetostriction constant λ of 1 × 10 ^-5 or less, and a saturation magnetization of 4πM _s is about 16000 ~. 18000Gau
A film of ss, 2 is an amorphous magnetic alloy film or Fe-Si-Al (sendust) film having a λ of 1 × 10 ^-5 or less and excellent in wear resistance. Reference numeral 3 in FIG. 3 (b) is an interlayer insulating film such as SiO ₂ or Si ₃ N ₄ . However, t ₁ , t ₂ <1000Å and t ₁ <2t ₂ are important conditions because uneven wear does not occur as will be shown later in Examples. In the same figure (b), the interlayer insulating film 3
Can be taken in consideration of the skin depth depending on the frequency region in which this laminated magnetic material is used, and the figure (b) is an example, and it is not always necessary to insert it in this way. It may be more spaced depending on the frequency, and is not absolutely necessary if the total film thickness is less than the skin depth at the frequency used.

After sandwiching the laminated magnetic material of the present invention shown in FIG. 1 and the conventional laminated magnetic material shown in FIGS. 2 and 3 with a ceramic substrate having relatively excellent wear resistance to form a head chip, Was attached to a normal VTR deck and a tape was run to perform an abrasion resistance test. The outline of the test results is shown in FIG. In the figure, (a) and (b) are sandwiched between the conventional type laminated magnetic materials shown in FIGS. 2 and 3 with a substrate, and (c) is the book shown in FIG. 1 (a). The laminated magnetic material of the invention is sandwiched between substrates. Although specific examples will be described in detail below, the general tendency is as shown in FIG. 4, and in the case of FIG. 4 (a), the insulating film such as SiO ₂ shown in FIG. Since the wear resistance is good, the Fe-Si film shown by 4 in the figure is unevenly worn and the touch with the tape is deteriorated. In order to avoid this, if the film thickness of SiO ₂ etc. in Fig. 5 is made thin, the overall wear becomes larger, and conversely, if the film thickness at this part is made thicker, the proportion of the Fe-Si magnetic film portion occupies relatively. Is decreased, and the saturation magnetization as a whole is decreased, and soft magnetism of the Fe—Si alloy film itself is impaired, which is not preferable.
In addition, in FIG. 2B, the Ni-Fe film indicated by 6 is relatively 4
Thinner than the Fe-Si film shown in Fig. 3 has a higher saturation magnetization as a whole, and the soft magnetism of the Fe-Si film is also improved, which is preferable for magnetic properties, but both have low wear resistance compared to the substrate. There is a disadvantage that the wear material becomes large. In the magnetic laminated film of the present invention shown in FIG. 3C, the film thicknesses of the Fe—Si film 1 and the amorphous alloy or the Fe—Si—Al (sendust) alloy film 2 are t ₁ and t ₂ , respectively. It was found that, as long as t ₁ <1000Å and t ₁ <2t ₂ , both the uneven wear and the overall wear can be suppressed to be small as shown in FIG. this is
At the same time the t ₁ itself following a sufficiently small 1000 Å, t ₁
It is considered that by setting <2 t ₂ , the Fe-Si film 1 having low wear resistance is protected by the adjacent magnetic film portion 2 having good wear resistance. Actually t ₁ > 1000Å, or even t ₁ <1000Å
It has been found that when t ₁ > 2t ₂ , the Fe-Si film portion 1 is unevenly worn and results similar to those in the case of FIG. Also the thickness of the film part 2
Since it has been found that the soft magnetism of the Fe-Si film is impaired when t ₂ is made thicker than 1000Å, it is desirable that t ₁ , t ₂ <1000Å and t ₁ <2t ₂ (1) after all. On the other hand, if t ₂ is less than 500Å,
It was found that the soft magnetism of the Fe-Si film of the film part 1 was further improved, but it was found that when the Fe-Si-Al alloy was used for the film part 2, the soft magnetism of the Fe-Si film was slightly deteriorated. . However, when an amorphous alloy is used for the film part 2, soft magnetism is not impaired even at t ₂ <500Å, and t ₁ , t ₂ <500Å and t ₁ <2t ₂ (2) It was found that the magnetic properties were improved, and the uneven wear of the film part 1 was suppressed to be smaller than the condition (1).

Heat treatment is effective for improving the magnetic properties, but when t ₁ and t ₂ are extremely small, interdiffusion between the film 1 and the film 2 becomes a problem during the heat treatment. In this case, it was found that the interdiffusion can be suppressed by interposing a film of Ag, Cu, Mg or the like, which is difficult to form a solid solution, between the films 1 and 2.

In order to obtain high magnetic permeability, the magnetostriction constant λ needs to be suppressed to 1 × 10 ⁻⁵ or less, but in the Fe—Si alloy film, this is satisfied when Si is around 6.5 weight percent (the balance is Fe). Although the Nako Fe-Si alloy film has a little difficulty in corrosion resistance, this can be improved by adding Cr, Ni, Nb, Ti, Ru, etc. or by nitriding. However, at this time, it is necessary to change the amount of Si in accordance with the amount of addition or the amount of nitriding to reduce λ.

In the Fe-Si-Al system, λ <1 × 1 in the so-called sendust composition region.
0 ^-5 and becomes, in the case of amorphous alloy, Co-Mn- mainly composed of Co (Fe) - (Si) -B system, that Co-Nb-Zr-based λ, etc. is sufficiently small I know.

Fe-Si system with λ <1 × 10 ^-5 and saturation magnetization 4πM _s 16000 ~ 18000
Gauss, Fe-Si-Al (Sendust) alloy system and amorphous alloy system, 4πM _s is 9000 ~ 10000Gauss, so the average <4πM _s > of this laminated material is 13000 ~ 14000Gauss, It has been found that when the film thickness is made extremely thin as in this patent, the average characteristics of both alloy systems can be obtained practically, and a magnetic material having high permeability and high saturation magnetic flux density can be obtained.

As described above, the laminated magnetic material of the present invention is a soft magnetic material having both wear resistance and high saturation magnetization, and is extremely useful in practice. The effects of the present invention will be shown by the following specific examples.

By laminating a <Example 1> 6.5wt% Fe-Si alloy film 1 and the _{Co 87 Nb 9 Zr 4 (at} %) by sputtering on a ceramic substrate an amorphous alloy film 2 alternately. Various multilayer films were prepared by changing the film thicknesses t ₁ and t ₂ of the films 1 and 2, and the various characteristics were as follows.

Note that 4πM _s uses a vibrating magnetometer, and H _c is B at 60 Hz.
The abrasion resistance test, which was obtained from the −H curve, was performed by mounting the sample on a normal VTR deck after processing it into a head chip shape, running the metal tape for 100 hours at room temperature, and removing it from the substrate surface as shown in FIG. The amount of uneven wear of the films 1 and 2 was measured by the Taly step.

<Example 2> A 6.5 wt% Fe-Si alloy film 1 was formed by the same sputtering method as in Example 1.
The same experiment was conducted by alternately stacking Fe ₈₅ Si _9.6 Al _5.4 (wt%) alloy film 2. The results were as follows.

<Example 3> A sample FP, 6.5 in which a 6.5 wt% Si-Fe film (film 1) and a Ni ₈₀ -Fe ₂₀ (at%) alloy film (film 1 ') were laminated by the sputtering method as in Example 1 Sample FI in which a wt% Si-Fe film (film 1) and a SiO ₂ film (film 3) are laminated, and a 6.5 wt% Si-Fe film, a Co ₈₇ Nb ₉ Zr ₄ amorphous alloy film (film 2) and SiO Create a sample FAI in which _two films are laminated,
The same experiment as in Example 1 was performed to compare the characteristics, and the results are shown below.

Figure 4 shows the wear of samples FI51, FP51, and FAI.
It becomes like (a), (b), and FIG.

From the above results, it is understood that the present invention is a laminated magnetic material having both soft magnetism, high saturation magnetization, and wear resistance.

<Example 4> As in Example 1, a 6.5 wt% Fe-Si film 1 and a Co ₈₇ Nb ₉ Zr ₄ amorphous alloy film 2 were laminated by a sputtering method, and 12 Å was provided between these films. 4 with an Ag film in between
Heat treatment was performed in a rotating magnetic field at 00 ° C. for 30 minutes. The results are shown below.

That is, the soft magnetism is more improved in the case where t ₁ and t ₂ are 300 Å or more by the heat treatment, but when t ₁ and t ₂ are about 50 Å, interdiffusion probably occurs between the films 1 and 2, and the soft magnetism is deteriorated. It seems to be done. Therefore, it is understood that the one in which the non-solid solution Ag film is interposed between the films 1 and 2 becomes a barrier of mutual diffusion and the soft magnetism is always improved by the heat treatment. Also Cu, Mg, etc.
Experiments showed that it had the same effect as.

EFFECTS OF THE INVENTION According to the present invention, it is possible to realize a magnetic material having excellent magnetic properties and high wear resistance.

[Brief description of drawings]

FIG. 1 is a sectional view of a laminated magnetic material in an embodiment of the present invention, FIGS. 2 and 3 are sectional views of a conventional laminated magnetic material, and FIGS. 4, 5, and 6 are after an abrasion resistance test. FIG. 6 is a cross-sectional view showing uneven wear of the sample. 1 ... Fe-Si film, 2 ... Amorphous alloy or Fe-Si-Al alloy film.

Claims (5)

[Claims] 1. A first thin film mainly composed of Fe and Si having a magnetostriction constant λ of 1 × 10 ⁻⁵ or less, and an amorphous alloy having the λ of 1 × 10 ⁻⁵ or less and excellent in abrasion resistance, or When the second thin films of the Fe-Si-Al-based alloy are alternately laminated and the film thicknesses of one layer of the first and second films are t ₁ and t ₂ , respectively, t ₁ and t ₂ <1000Å and t ₁ <2t ₂ < ₁ > A laminated magnetic material characterized by the following: 2. The laminated magnetic material according to claim ₁ , wherein t ₁ , t ₂ <500Å and t ₁ <2t ₂ . 3. The laminated magnetic material according to claim 1, wherein an amorphous alloy film is used as the second film. 4. A patent characterized in that a film which is hard to form a solid solution with Fe-Si such as Ag, Cu, and Mg and an amorphous alloy is arranged between the first and second films at an appropriate interval. The laminated magnetic material according to claim 1. 5. A laminated magnetic layer according to any one of claims 2 to 4, wherein an insulating film is arranged between the first and second films at an appropriate interval. material.