JPH03132006A - Multilayer magnetic film and magnetic head using this film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a multilayer magnetic film having high saturation magnetic flux density and high magnetic permeability, and particularly to magnetic heads used in magnetic disk drives, VTRs, etc., and core materials of magnetic heads. This invention relates to a multilayer magnetic film with high thermal stability suitable for.

[Conventional technology]

With the increasing density of magnetic recording, Metal in Ga
p) Heads have been attracting attention recently. Because MIG heads require a high-temperature process called glass bonding,
A magnetic film with high thermal stability (soft magnetic properties are not degraded by heat treatment) is required. Magnetic films with relatively high thermal stability used in MIG heads include Co-based amorphous alloys, Sendust alloys, and even Fe.

Magnetic alloys containing nitrogen, such as Co, Ni)MN, are known. Here, M is Zr.

The metal is selected from the group consisting of Nb, Ti, Mo, Ta, Hf, Cr, and W.

[Problem to be solved by the invention]

In Co-based amorphous alloys, Sendust alloys (Fe, Co, Ni) MN alloys, etc., as described in the above prior art, the saturation magnetic flux density of the magnetic film exhibiting characteristics suitable for use in magnetic heads is The maximum is 1.4-1.5T.

An object of the present invention is to provide a magnetic film that has thermal stability equivalent to or better than that of the above-mentioned conventional technology and has an even better high saturation magnetic flux density, and a magnetic head for high-density magnetic recording using the same. There is a particular thing.

[Means to solve the problem]

The above object is achieved by constructing a multilayer magnetic film from an Fe-based alloy thin film and a nitride-based nonmagnetic thin film.

Further, by using the multilayer magnetic film of the present invention in at least a part of the magnetic circuit of a magnetic head, a magnetic head having excellent recording and reproducing characteristics can be obtained.

[Effect]

Nitride-based nonmagnetic thin films such as VN, TaN, and TiN are amorphous when they are formed, and when heat-treated at high temperatures, metastable nitrogen in the film is released to the outside of the film.

Therefore, when a multilayer magnetic film consisting of an Fe-based alloy thin film and a nitride-based nonmagnetic thin film as described above is heat-treated at high temperature, F
Nitrogen diffuses into the e-based alloy thin film and precipitates nitride microcrystals in the film. Precipitation of such microcrystals suppresses crystal grain growth, thereby improving the thermal stability of the film. Moreover, since the multilayer magnetic film has a high saturation magnetic flux density and high magnetic permeability, by using it in a part of the magnetic circuit of the magnetic head, a magnetic head with excellent recording and reproducing characteristics can be obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to a diagram.

[Example 1] A dual ion beam sputtering apparatus was used to prepare a multilayer magnetic film. Sputtering was performed under the following conditions.

Ion gas ArAr gas pressure
2.5X10-2Pa ion gun acceleration voltage for deposition 1200V ion gun ion current for deposition
120mA ion gun acceleration voltage for substrate irradiation 20
Ion gun for 0V substrate irradiation Ion current: 40 mA Target-substrate distance: 127 mm The cross-sectional structure of the prepared multilayer magnetic film is shown in FIG.

In this embodiment, the magnetic film 11 is made of Fe-3 with a film thickness of 450 mm.
at%C alloy, film thickness 50 as nitride-based nonmagnetic thin film 12
As the human TiN film and the substrate 13, 7059 glass manufactured by Conning Co., Ltd. and photoceram were used. Here, the heat treatment temperature is 70
Characteristic evaluation of the membrane at 0°C was performed using photoceram. The number of magnetic film layers was 10, and the total film thickness of the multilayer magnetic film was about 0.5 μm.

In addition, for comparison with this example, a magnetic film using an Fe-3at%C alloy with a thickness of 450 mm as the magnetic film 11 and a permalloy film with a thickness of 50 mm instead of the nitride-based non-magnetic thin film 12 was used. A multilayer film with 10 layers and a total thickness of about 0.5 μm was also produced at the same time. In order to examine the thermal stability of these films, heat treatment was performed within the range of 300 to 700°C, and changes in soft magnetic properties were examined. The heat treatment conditions were to maintain each of the above temperatures for 1 hour in an argon gas atmosphere. The experimental results are shown in Table 1.

As shown in Table 1 above, the Fe-3at%C/TiN multilayer magnetic film exhibits excellent soft magnetic properties up to a heat treatment temperature of 500°C or higher, and even at a heat treatment temperature of 550'C, the film ratio The magnetic permeability showed a value of 1000 or more. In contrast,
In the Fe-3at%C/NiFe multilayer magnetic film, the relative magnetic permeability of the film shows a value of 1000 or more when the heat treatment temperature is up to 500℃, but the soft magnetic properties reach the maximum value when the heat treatment temperature is 400℃. . As a result, the thermal stability of the film was improved by about 100° C. according to the present invention. In addition, multilayering with TiN is N
It was also found that the soft magnetic properties are better than a film multilayered with iFe, and that the soft magnetic properties are further improved by heat treatment. Since the nitride-based nonmagnetic thin film used in the present invention is amorphous during film formation, a flat film with no unevenness is formed, which is softer than a multilayer magnetic film in which a crystalline material such as N1Fa is inserted. This is also considered to be one of the reasons for the excellent magnetic properties. In the invention, Ti is used as a nitride-based nonmagnetic thin film.
N was used, but T a N , Z r N , N
bN, AQN.

Cr 2 N + V N + Hf N 2M O2
It was confirmed that other nitrides such as N have similar effects. Here, the valence of the nitride-based nonmagnetic thin film is expressed as, for example, TiN, but it is clear that it is not necessarily possible to form only a film with such a fixed composition, and this invention is representative of this. I used a display method like this. In the present invention, a nitride-based nonmagnetic thin film is inserted into an Fe-based alloy thin film, so the saturation magnetic flux density of the film is slightly reduced.
The saturation magnetic flux density of the multilayer magnetic film was as high as 1.9T. For reference, the saturation magnetic flux density of the Fe-3at%C/NiFe multilayer magnetic film is 2. It was OT.

[Example 2] In this example, the magnetic film 11 is made of Fe-3 with a film thickness of 450 mm.
at%C-1at%Ta alloy, nitride-based nonmagnetic thin film 12
As the substrate 13, 7059 glass manufactured by Corning Co., Ltd. and Photoceram were used. The number of magnetic film layers was 10, and the total film thickness of the multilayer magnetic film was about 0.5 μm. 30 to check the thermal stability of the film as in Example 1.
Heat treatment was performed within the range of 0 to 700°C to examine changes in soft magnetic properties. Table 2 shows the measurement results, and also shows the results of the Fe-3at%C/NiFe multilayer film shown in Example 1 for comparison.

As shown in the table above, Fe-3at%C-1at%Ta
/ TiN multilayer magnetic film has a heat treatment temperature of 600°
Shows excellent soft magnetic properties up to C or higher, and heat treatment temperature is 65
Even at 0°C, the relative permeability of the material was as high as 1000. From this result, the thermal stability of the film was improved by 150 to 200°C by the present invention. In the present invention, TiN was used as the nitride-based nonmagnetic thin film, but TaN, Z
r N, N b N.

It was confirmed that other nitrides such as AQN, VN, I(fN, CrzN+MO2N) have similar effects.Also, in the present invention, Ta was added to the magnetic film, but T
i, V, Zr, Ntz W, Mo, B.

It has been found that addition of Cr, Hf, etc. is also effective for increasing the thermal stability of the multilayer magnetic film according to the present invention. In Table 2, the multilayer magnetic film (Fe-3at%C
-1at%Ta/TiN) appears to have deteriorated rapidly after heat treatment at 700°C, but this is due to the use of photoceram, a crystallized glass whose surface properties are poorer than that of glass, as the substrate. seems to be doing so. By the way, the soft magnetic properties of the film formed on the ceramic substrate are worse than those of the glass substrate.

In order to investigate the cause of the improved thermal stability of the multilayer magnetic film according to the present invention, the composition of the film heat-treated at 600°C was analyzed in the film depth direction using AES and SIMS. As a result, it was confirmed that in the multilayer magnetic film according to the present invention, although mutual diffusion occurred between the Fe-based alloy thin film and the nitride-based nonmagnetic thin film, the multilayer film structure was maintained even after heat treatment at high temperatures. It was done.

Furthermore, a concentration distribution of nitrogen was confirmed in the magnetic film, although it was slight. On the other hand, Fe-3at%C/N x
In the Fe multilayer magnetic film, the concentration distribution in the film is made uniform, probably due to mutual diffusion, and the multilayer film structure is hardly visible. Since such a change in the multilayer film structure due to heat treatment is thought to affect the crystal grain size, the average crystal grain size of the film was determined from observation of the cross-sectional structure using an X-ray diffraction method and an electron microscope. FIG. 2 shows the results of examining changes in crystal grain size with respect to heat treatment temperature. The crystal grain size of the multilayer magnetic film according to the present invention is approximately 120 at a heat treatment temperature of 300°C;
It also appears that grain growth is suppressed by about 170 people at 700°C and about 200 people at 700°C. On the other hand, F
In the e-3at%C/NiFe multilayer magnetic film, the crystal grain size is about 150 when the heat treatment temperature is 300℃, and the crystal grain size is about 60℃ when the heat treatment temperature is 300℃.
It was found that when the temperature reached 0°C, the crystal grains grew 2 to 3 times as much as about 400 people. In addition, from the cross-sectional observation results, a multilayer structure was confirmed in the multilayer magnetic film according to the present invention, but Fe-3a
In the t%C/NiFe multilayer magnetic film, almost no multilayer structure can be observed, which also agrees with the compositional analysis results. These results suggest that grain growth and interdiffusion are responsible for changes in the soft magnetic properties of the film. The reason why crystal grain growth is suppressed in the multilayer magnetic film according to the present invention is considered to be that nitride microcrystals are precipitated in the magnetic film by high-temperature heat treatment, and this suppresses crystal grain growth. As a result of analysis using high-resolution EPMA, TaN was observed around the crystal grains constituting the magnetic film. In addition, since diffraction lines that appear to be TaN can be seen in the diffraction pattern obtained using a transmission electron microscope, it is thought that the precipitation of such nitride microcrystals is related to the thermal stability of the crotch.

[Example 3] A magnetic head for a VTR was manufactured using a multilayer magnetic film as shown in FIG. In this embodiment, the magnetic film 11 has a film thickness of 9
A 50% Fe-3at%C-1at%Ta alloy and a 50% TiN film were used as the nitride-based nonmagnetic thin film 12.

The magnetic film was laminated 200 times, and the film thickness was about 20 μm.

The manufacturing process of the VTR magnetic head 90 shown in FIG. 3 will be described below.

A substrate 82 made of Mn-Zn ferrite having grooves 81 as shown in FIG. 3(a) is prepared, and as shown in FIG. 3(b), the surface of the substrate 82 has the above multilayer structure with a thickness of about 20 μm. Multilayer magnetic film 83 was fabricated by ion beam sputtering. Next, as shown in Fig. 3(C), <pb
The groove 81 is filled with glass 84, and further as shown in FIG.
As shown in d), the surface of the PB glass 84 is polished to form a gap forming surface 85, and the head core semi-dead block 8 is polished.
6 was produced. Furthermore, a 5iOz film serving as a gap material is formed on the gap forming surface 85 by sputtering,
As shown in FIG. 3(e), a head core half-closed block 88 having a winding window 87 and the above-mentioned rad core half-closed block 86
were stacked together with a gap material in between and heated at a temperature of 500° C. for 30 minutes to melt and solidify the PB glass 84 again to produce a bonded block 89. Further, the VTR magnetic head 90 shown in FIG. 3(f) was obtained by cutting along the two-dot chain line shown in FIG. 3(e).

The recording and reproducing characteristics of the magnetic head of the present invention manufactured through the above steps were measured using a metal tape with a coercive force of 14,000e. The results are shown in Table 3. For reference, results for a magnetic head using a Fe-3at%C/NiFe multilayer magnetic film are also shown.

Table 3 As shown in Table 3, it was found that the reproduction output of the magnetic head using the multilayer magnetic film according to the present invention was higher than that of the magnetic head using the conventional multilayer magnetic film. This is because in the conventional multilayer magnetic film, the soft magnetic properties of the multilayer magnetic film may deteriorate during the glass bonding process using Pb-based glass, as shown in Table 1. With the multilayer magnetic film, there is no deterioration of the crotch, but rather the soft magnetic properties are improved, which is probably why the difference in reproduction output was observed.

〔Effect of the invention〕

As explained above, a multilayer magnetic film that combines a Fe-based alloy thin film and a nitride-based nonmagnetic thin film has a high saturation magnetic flux density.
Furthermore, it exhibits excellent soft magnetic properties and high thermal stability. Also,
By using the multilayer magnetic film of the present invention in at least a portion of the magnetic circuit of a magnetic head, a magnetic head having excellent recording and reproducing characteristics can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the multilayer magnetic film of the present invention, Fig. 2 is a relationship between heat treatment temperature and crystal grain size, and Fig. 3 is a perspective view showing the manufacturing process of a magnetic head for a VTR using the multilayer magnetic film of the present invention. It is a diagram. 11...Magnetic film, 12...Nitride-based nonmagnetic thin film, 13
. . . Substrate, 81 . . Groove, 82 .
7... Winding window, 88... Head core semi-dead block with winding window, 89... Joining block, 90... VT
Magnetic head for R. fig. fig. fig.

Claims (3)

[Claims] 1. Additional elements include C, B, Ta, Ti, V, Zr,
At least one selected from Nb, W, Mo, Cr, Hf
Fe-based alloy thin film containing more than one element and VN
, TaN, TiN, ZrN, NbN, AlN, HfN,
A multilayer magnetic film characterized by laminating a nitride-based nonmagnetic thin film containing at least one kind of nitride selected from Cr_2N and Mo_2N. 2. The multilayer magnetic film according to claim 1, wherein the average grain size of the alloy thin film is 200 Å or less. 3. A magnetic head characterized in that the multilayer magnetic film according to claim 1 or 2 is used in at least a part of a magnetic circuit.