JPH0817129B2 - Magnetic alloy film and manufacturing method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic alloy film that constitutes a soft magnetic material for a magnetic head or the like, and a manufacturing method thereof.

2. Description of the Related Art Conventionally, as a magnetic head material, a sendust alloy containing Fe-Si-Al as a main component, an amorphous alloy such as Co-Nb-Zr, or a ferrite material with low high frequency loss is used. However, with the recent increase in information density, recording media are also shifting to those having higher coercive force than before, and soft magnetic materials with higher saturation magnetization, 4πMs, are required. Is becoming. On the other hand, as a magnetic material for a magnetic head, in addition to high saturation magnetization, good corrosion resistance and wear resistance are required at the same time. Ferrite has excellent corrosion resistance and wear resistance, but 4πMs is 5
~ 6000G, not enough. Amorphous alloys have excellent magnetic characteristics, but are poor in heat resistance, and crystallize at high temperatures to deteriorate the characteristics. Therefore, as a material that can withstand the magnetic head gap bonding process, 4πMs is as high as 10,000G. Only the things have been obtained. Although the sendust alloy has a 4πMs value of about 12000G, it has poor corrosion resistance, so it is necessary to add Cr and the like, and therefore it cannot be practically used at 10000G or more, and also has poor wear resistance. Since both the Sendust alloy and the amorphous alloy have small electric resistance, the skin depth is becoming smaller than the track width along with the increase in frequency, and measures are taken to insert an interlayer insulating layer, but from the standpoint of spacing loss. Not preferable.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, a metal material having a high saturation magnetization is inferior in corrosion resistance or wear resistance, and an oxide material excellent in corrosion resistance and wear resistance has a saturation magnetization. Not enough. It is an object of the present invention to realize an alloy film which has a high saturation magnetization which is required and which is excellent in corrosion resistance and wear resistance and which can be used as a soft magnetic material for a magnetic head having a high electric resistance.

Means for Solving the Problems The magnetic alloy film according to the present invention has an average composition of T
A magnetic alloy film represented by XN, wherein N in the nitride film is a multilayer film in which a non-nitride film and a nitride film are alternately laminated.
Is inter-layer diffused into the non-nitride film, whereby at least N is composition-modulated in the film thickness direction. The method for producing a magnetic alloy film according to the present invention uses a sputtering method to form a multilayer film in which a nitride film having a composition of T _a X _b N _c and a non-nitride film having a composition of T _a ′ X _b ′ are alternately laminated. And a heat treatment step of heating the multilayer film to diffuse N into the non-nitride film and compositionally modulating at least N in the film thickness direction. However, T is one or more elements selected from the group consisting of Fe, Ca, Ni, X is one or more elements selected from the group consisting of Si, Ge, Ga, and N is nitrogen. And the atomic composition% Is.

When nitriding a soft magnetic alloy for a magnetic head that has sufficiently high saturation magnetization and excellent soft magnetic properties, corrosion resistance and wear resistance are improved, but the excellent soft magnetic properties are impaired and It was found from experiments that the deteriorated magnetic properties cannot be easily recovered even by heat treatment. When the nitrided magnetic alloy film and the non-nitrided magnetic alloy film have a multilayer structure, a magnetic head material having excellent wear resistance can be obtained without deteriorating the soft magnetic characteristics. When heat treatment is applied to this multilayer film,
Due to the inter-layer diffusion, nitrogen also penetrates into the portion that was the non-nitride film before the heat treatment, and becomes a composition-modulated nitride film in which the composition of nitrogen is at least modulated. Unlike the single-layer nitride alloy film in which nitrogen is uniformly distributed from the beginning, the obtained composition-modulated nitride film does not deteriorate in soft magnetic properties even after heat treatment, and has corrosion resistance and wear resistance. Is excellent. When it is nitrided again,
Since the electrical resistance is increased and the skin depth is increased, a material more suitable for high frequency recording accompanying higher recording density can be obtained.

Example The nitride film laminated in the present invention has a composition of Ta Xb Nc. However, T is one or more elements selected from the group consisting of Fe, Co and Ni, X is one or more elements selected from the group consisting of Si, Ge and Ga, and N is It is nitrogen. In order to obtain sufficient saturation magnetization, 4πMs, it is necessary to have a78, b28, c20 in atomic%, and to obtain sufficient corrosion resistance and wear resistance, it is necessary to fill a98, c1. It has been found from experiments that at least b2 is required to obtain further excellent soft magnetism.

The composition of the nitriding magnetic alloy film in the present invention is as described above. However, in the case of a single-layer film, even if it is within the above composition range, it does not exhibit good soft magnetic characteristics, so that the thickness t It is necessary to have a structure in which a nitrided alloy film and a non-nitrided alloy film having a thickness t ′ are alternately laminated. FIG. 1a shows an example of the dependence of the amount of elements in the film on the depth direction. The wear resistance of the multi-layer structure film thus obtained is high in the nitride film portion and low in the non-nitride film portion, and uneven wear may occur. Therefore, the thickness of each film is tt '/ 2. Is desirable. An example of the dependency of the amount of elements in the multilayer film after heat treatment in the depth direction is shown in FIG. 1b. Nitrogen diffuses in the non-nitride film to obtain a composition modulation film having a period of λ = t + t '. Since nitrogen is contained in the entire film after the heat treatment, a magnetic material having improved corrosion resistance and wear resistance in all parts of the film can be obtained. This is also preferable in terms of preventing uneven wear. At this time, the pattern of compositional modulation after diffusion may be various depending on the easiness of formation of the nitrides of T and X in the constituent elements (free energy of formation) and the easiness of movement of the formed nitride. Therefore, the pattern of composition modulation after heat treatment of the multilayer film of FIG. 1a differs depending on the types of T and X, and is not necessarily uniquely determined as shown in FIG. 2b. If the periodicity of modulation of the obtained composition-modulated film is too large, the properties of the nitride film with the thickness t in the multilayer structure film become close to those of the single-layer film, and good soft magnetism cannot be obtained even after the heat treatment. , Λ20
Must be 00Å. Specific examples will be described below.

Using a target having a composition of Fe _x Si _y (x + y = 100,4y24 atom%), Ar gas pressure was controlled by an rf sputtering device.
The film was formed at a fixed power of 1.1 × 10 ^-2 Torr and an input power of 350 W in an atmosphere having a nitrogen gas partial pressure of 0 to 50%. FIG. 2 shows the nitrogen concentration dependence of the saturation magnetization, 4πMs, of the film obtained by using the target having the composition of Fe ₈₀ Si ₂₀ (atomic%). The composition of the obtained non-nitride film is Fe ₈₂ Si ₁₈ (atomic%). In the case of a multilayer film, 4πMs is almost determined by the average composition of the entire film. Depending on the type of T or X in TaXbNc, there is a case where 4πMs does not depend on the nitrogen concentration or increases within a certain range.

However, if the nitrogen content exceeds 20 atomic%, in all cases, 4πMs decreases, and it becomes difficult to obtain good soft magnetism even after the heat treatment, so C20 atomic% is necessary. The corrosion resistance test is performed by immersing the sputtered film in pure water for 24 hours at room temperature.
It was carried out depending on the rust occurrence after being left for a time. The electrical resistance was measured by the 4-terminal method. Table 1 shows the changes in corrosion resistance and electric resistance when the nitrogen concentration was changed. The results of the corrosion resistance test were represented by x (those with rust), Δ (those with little rust), and ◯ (no rust). The corrosion resistance of the composition-modulated nitride film is almost determined by the average composition. Table 1 shows the composition of the single-layer film and the average composition of the composition-modulated nitride film. Electric resistance increases due to nitriding, but the skin depth increases to several μs as the frequency of signals increases.
For metal materials having a thickness of about m, measures are currently taken to insert an interlayer insulating film, but it is desirable to increase the electric resistance and increase the skin depth in order to reduce spacing loss.

Naturally, the corrosion resistance depends on the types of T and X and a and b, but in order to recognize the effect of suppressing the formation of rust, it must be at least C1%, and as N increases. It was found that the corrosion resistance was improved. In Figure 3, C
= 0% Fe ₈₂ Si ₁₈ film at T = 510 ° C. in a magnetic field for 30 minutes before (a) and after (b) heat treatment at 60 Hz B−
The H curve is shown. FIG. 4 shows a nitride monolayer film before (a) and after (b) similar heat treatment, and in FIG. 5, a multilayer film (a) at t = t ′ = 200Å and after heat treatment. BH curves of the composition modulation film (b) are shown respectively.
However, the nitride single-phase film and the nitride film portion in the multilayer film are
Nitrogen is about 12 atom%. Table 2 summarizes the saturation magnetization (4πMs) of the composition-modulated nitride film, the nitride single-layer film, and the non-nitride film, the results of the corrosion resistance test, and the Knube hardness. The saturation magnetization is measured by an oscillating magnetometer.

FIG. 6 shows the λ (composition modulation wavelength) dependence of the coercive force Hc of the composition-modulated nitride film after heat treatment in a magnetic field at T = 510 ° C. for 30 minutes. As can be seen from FIG. 6, the composition modulation film has the best soft magnetic characteristics. The N content of the nitride modulation film shown in this figure is 6 atom%, which is 1/2 of that of the nitride monolayer film, but it is satisfactory even if the N nitride film with 6 atom% N is heat-treated. Since it is not possible to obtain excellent soft magnetic properties, it is necessary to have a composition-modulated structure. However, if the heat treatment temperature is too high,
Alternatively, if the treatment time is too long, Hc may increase again depending on the composition, so it is necessary to select an appropriate temperature and treatment time. The hardness of the single-layer nitride film and the composition-modulated nitride film are not necessarily the same even if they have the same composition,
In both the nitride film and the single layer film having the same composition modulation wavelength λ, the hardness increases as N increases. However, as described above, an excessive amount of nitrogen reduces the saturation magnetization, so it is desirable to keep it to 20 atomic% or less. The protective power of the nitride single-layer film is remarkably increased as compared with the non-nitride film, and as can be seen from FIG. 4b, good soft magnetic characteristics cannot be obtained even after the heat treatment, whereas as shown in FIG. As for the composition modulation film, when the composition modulation wavelength λ is 2000 Å or less, the coercive force is significantly reduced.

The above-mentioned nitriding improves the corrosion resistance and wear resistance not only for Fe-Si alloys but also for Fe-Co-Si alloys, Fe-Si-Ga alloys, Fe-
It was found that the same can be seen for Ge-Ga alloys, and that the same effect can be obtained for multilayering to obtain good soft magnetic characteristics. Table 3 shows the corrosion resistance, wear resistance, saturation magnetization, coercive force after heat treatment, and specific resistance of the monolayer films of these alloys and the nitride modulation film. However, wear resistance is
It was measured by the amount of wear after the tape was run for 100 hours using a VTR deck. Table 3 shows the relative value of the amount of wear of the nitrided modulation film when the amount of wear of the non-nitrided film is 1. The modulation wavelengths of the nitride modulation films in Table 3 are all 500Å. However, because nitriding may shift the magnetic anisotropy and the saturation magnetostriction, and the composition that gives the best soft magnetic characteristics may shift, in that case, it is necessary to select the optimum composition according to the nitrogen concentration.

EFFECTS OF THE INVENTION The magnetic alloy film according to the present invention has a high saturation magnetization (10000 G) which is equal to or higher than that of the conventional magnetic alloy, is excellent in corrosion resistance and wear resistance, and has high electric resistance. It is a magnetic alloy suitable for heads and the like.

[Brief description of drawings]

FIG. 1 (a) is a graph showing a composition profile in the depth direction of a nitride multilayer film, FIG. 1 (b) is a graph showing a composition profile in the depth direction of a nitride modulation film, and FIG. 2 is a Fe-Si nitride film.
Graph showing nitrogen concentration dependence of saturation magnetization of alloy film, third
FIG. 3A is a graph showing a BH curve before heat treatment of the Fe-Si alloy film, and FIG. 3B is a BH curve after heat treatment of the alloy film.
Fig. 4 (b) is a graph showing a curve, Fig. 4 (a) is a graph showing a BH curve before heat treatment of the Fe-Si nitride single layer film.
Is a graph showing a B-H curve after heat treatment of the alloy film, FIG. 5 (a) is a graph showing a B-H curve of a Fe-Si nitride multilayer film, and FIG. 5 (b) is a nitride-modulated Fe-Si film. FIG. 6 is a graph showing the B-H curve of FIG. 6 and FIG. 6 is a graph showing the modulation wavelength dependence of the coercive force of the nitride modulation Fe—Si film.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G11B 5/706

Claims (4)

[Claims] 1. The average composition of the entire film is TX in atomic composition%.
In a magnetic alloy film represented by N, in which a non-nitride film made of TX and a nitride film made of TXN are alternately laminated, by intercalating N in the nitride film into the non-nitride film, A magnetic alloy film in which at least N is composition-modulated in the thickness direction of the film. However, T is Fe, Co, Ni
One or more elements selected from the group consisting of
X is one or more elements selected from the group consisting of Si, Ge and Ga, and N is nitrogen. Is. 2. The magnetic alloy film according to claim 1, wherein the composition modulation wavelength λ is λ ≦ 2000Å. 3. A sputtering method is used to form a multilayer film in which a nitride film having _a composition of T _a X _b N _{C in} atomic composition% and a non-nitride film having a composition of T _a ′ X _b ′ are alternately laminated. A method of manufacturing a magnetic alloy film, comprising: a step of heating the multilayer film to diffuse N into a non-nitride film, and a heat treatment step of compositionally modifying at least N in a thickness direction of the film. However, T is F
one or more elements selected from the group consisting of e, Co and Ni, X is one or more elements selected from the group consisting of Si, Ge and Ga, N is nitrogen Is. 4. When the film thicknesses of the T _a X _b N _C nitride film and the T _a ′ X _b ′ non-nitride film are respectively t and t ′ (Å), t ≦ 1000 Å and t
4. The method for manufacturing a magnetic alloy film according to claim 3, wherein ≧ t ′ / 2.