JPH0626167B2 - Soft magnetic thin film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a soft magnetic thin film used as a core material of a magnetic head or the like, and particularly to a soft magnetic thin film containing Fe, Al and Si as main components. The present invention relates to the improvement of magnetic properties of.

[Outline of Invention]

The present invention relates to a soft magnetic thin film made of an Fe-Al-Si alloy material, wherein Fe-Al-Si magnetic thin film and Ni-containing Fe-A.
By alternately laminating 1-Si magnetic thin films, it is intended to achieve a low coercive force and a high magnetic permeability, which cannot be realized by a single-layer film.

[Conventional technology]

For example, in a magnetic recording / reproducing apparatus such as a VTR (video tape recorder), high density and high frequency of recording signals are being advanced, and in response to this high density recording, magnetic powder is used as a magnetic recording medium. A so-called metal tape using a powder of a ferromagnetic metal such as Fe, Al and Si, and a so-called vapor deposition tape in which a ferromagnetic metal material is deposited on a base film by a method such as a vapor deposition method are being put to practical use. .

Since this type of magnetic recording medium has a high coercive force, the head material of the magnetic head used for recording / reproducing is required to have a high saturation magnetic flux density. For example, a ferrite material, which has been widely used as a head material in the related art, has a low saturation magnetic flux density and cannot cope with this increase in coercive force.

Therefore, conventionally, in order to support these high coercive force magnetic recording media, a soft magnetic thin film having a high saturation magnetic flux density is deposited on a non-magnetic substrate such as ceramics or a magnetic substrate such as ferrite. There have been proposed a composite type magnetic head in which a magnetic gap is formed by abutting each other, a thin film magnetic head in which a soft magnetic thin film or a conductor thin film has a multilayer laminated structure with an insulating film interposed therebetween, and the like.

As a soft magnetic thin film used for the above composite type magnetic head or thin film magnetic head, an Fe—Al—Si magnetic thin film that is thermally stable and has a high saturation magnetic flux density is known.

By the way, F produced by a sputtering method is usually used.
The e-Al-Si magnetic thin film has large anisotropy and internal stress in the film due to phase transition and columnar growth during film formation, difference in thermal expansion from the underlying substrate, etc. Be hindered. For example, Fe- formed by the sputtering method
The coercive force of the Al-Si based magnetic thin film is almost an order of magnitude higher than that of the bulk. In particular, in a film sputtered from an oblique direction, the columnar structure is remarkably formed due to the oblique incidence effect, so that the magnetic characteristics are significantly deteriorated.

When the holding force is large as described above, when a large magnetic field is applied for recording on a magnetic recording medium such as a metal tape, the Fe—Al—Si magnetic thin film as the core material may be magnetized. is there. Therefore, in order to improve the characteristics of the magnetic head, it is necessary to further improve the magnetic characteristics of the soft magnetic thin film including the coercive force.

As a method for improving the coercive force of the soft magnetic thin film, conventionally, there is a method of stacking a magnetic layer and a non-magnetic layer.

However, even in the soft magnetic film in which the magnetic material layer and the non-magnetic material layer described above are laminated, there is a limit in suppressing the coercive force, and
Since completely different materials are laminated, the laminating method is complicated.

[Problems to be solved by the invention]

As is clear from the above description of the prior art, further improvement in coercive force, magnetic permeability, etc. is demanded for the soft magnetic thin film having a high saturation magnetic flux density.

In view of such a situation, the present invention has an extremely small holding force,
An object is to provide a soft magnetic thin film having high magnetic permeability.

[Means for solving problems]

The inventors of the present invention have earnestly studied that they cannot achieve the above-mentioned object, and as a result, Fe--Al--Si magnetic thin film and nitrogen-containing F
The inventors have found that stacking an e-Al-Si-based magnetic thin film is effective in suppressing coercive force and improving magnetic permeability, and have completed the present invention. The composition ranges of Al and Si are 2 to 1 respectively.
A magnetic thin film containing 0 wt% Al and 4 to 15 wt% Si;
Fe, Al, and Si as main components, and the composition ranges of Al and Si are 2 to 10 wt% Al and 4 to 15 wt% S, respectively.
i, and is further laminated with a magnetic thin film containing 0.005 to 4% by weight of nitrogen.

In the present invention, the composition range of Fe, Al, and Si contained in the nitrogen-free Fe-Al-Si magnetic thin film is such that the Al content is 2 to 10 wt% and the Si content is 4%.
It is preferable that the content is ˜15% by weight and the balance is Fe. In other words, the Fe-Al-Si-based magnetic thin film _{Fe a Al b Si c (a} , b, c represents the weight ratio of each component.) And when, the composition range 70 ≦ a ≦ 95 2 ≦ It is desirable that b ≦ 10 4 ≦ c ≦ 15 a + b + c = 100. If the amount of Al or Si is too small, or conversely, too much, the magnetic characteristics will deteriorate.

It is also possible to replace part of the Fe with at least one of Co and Ni.

By substituting a part of Fe for Co, the saturation magnetic flux density can be increased. In particular, the maximum saturation magnetic flux density can be obtained by replacing 40% by weight of Fe with Co.
The substitution amount of Co is preferably in the range of 0 to 60% by weight with respect to Fe.

Similarly, by substituting a part of Fe with Ni,
The magnetic permeability can be kept high without decreasing the saturation magnetic flux density. The Ni substitution amount is preferably in the range of 0 to 40% by weight with respect to Fe.

Further, various elements may be added as an additive to the above Fe-Al-Si magnetic thin film in order to improve the corrosion resistance and the wear resistance. The elements used as the additive include IIIa group elements including lanthanum series elements such as Sc, Y, La, Ca, Nd, and Gd, and IVa such as Ti, Zr, and Hr.
Group Va elements such as V, Nb and Ta, Cr, Mo,
VIa group element such as W, VIIa group element such as Mn, Tc, Re, Ib group element such as Cu, Ag, Au, Ga, In, G
e, Sn, Sb and the like. One kind or two or more kinds of these additives are combined and added in the range of 0 to 10% by weight. That is, the additive is T, and Fe--Al
The -Si-based magnetic thin film _{Fe a Al b Si c T d} (a, b, c, d represent the weight ratios of each component.) And when, the composition range 65 ≦ a ≦ 95 2 ≦ b ≦ It is desirable that 10 4 ≦ c ≦ 150 0 ≦ d ≦ 10 a + b + c + d = 100. The amount of the above additive is 10
If it exceeds the weight%, the magnetic properties may be deteriorated.

Alternatively, as the additive, Ru, Rh, Pd, Os,
One or more platinum group elements such as Ir and Pt may be added.
In this case, the addition amount of the platinum group element is 40% by weight.
The following is preferable. If the added amount exceeds 40% by weight, the magnetic properties may be deteriorated.

Further, it is also possible to add both the above-mentioned additives such as IIIa group element and IVa group element and the above platinum group element. In this case, the composition range includes the above group IIIa elements, I
The additive such as Va group element is T, the above platinum group element is P,
The Fe-Al-Si-based magnetic thin film _{Fe a Al b Si c T d} P e (a, b, c, d, e represents. The weight ratio of each component) is taken as, the composition range 55 ≦ It is preferable that a ≦ 95 2 ≦ b ≦ 10 4 ≦ c ≦ 15 0 ≦ d ≦ 10 0 ≦ e ≦ 40 a + b + c + d + e = 100, and that the platinum group element is a platinum group element of the fifth period, that is, Ru, It is desirable that d + e ≦ 20 when Rh and Pd are used and d + e ≦ 40 when the platinum group element of the sixth period, that is, Os, Ir, and Pt is used as the platinum group element. Addition of an additive exceeding the above range may deteriorate the magnetic properties.

On the other hand, Fe-containing nitrogen, which is laminated with the magnetic thin film,
The composition range of Al, Si and other additives contained in the Al—Si magnetic thin film is the above-mentioned Fe—Al—Si.
Same as the magnetic thin film, but with the addition of 0.0
It is necessary to contain 05 to 4% by weight.

Thus, a magnetic thin film containing the nitrogen _{Fe a Al b Si c N f} (a, b, c, f represents. The weight ratio of each component) is assumed to be, the composition range is 70 ≦ a ≦ 95 2 ≦ b ≦ 10 4 ≦ c ≦ 15 0.005 ≦ f ≦ 15 a + b + c + f = 100, and Fe _a Al _b Si _c T _d N _f (a, b, c, d, f is the weight ratio of each component) , And T represents an additive), the composition range thereof is 65 ≦ a ≦ 95 2 ≦ b ≦ 10 4 ≦ c ≦ 150 ≦ d ≦ 10 0.005 ≦ f ≦ 4 a + b + c + d + f = 100 Furthermore, _{Fe a Al b Si c T d} P e N f (a, b, c, d, e, f represents the weight ratio of each component, T
Represents an additive, and P represents a platinum group element. ), The composition range is 55 ≤ a ≤ 95 2 ≤ b ≤ 10 4 ≤ c ≤ 150 0 ≤ d ≤ 10 0 ≤ e ≤ 40 0.005 ≤ f ≤ 4 a + b + c + d + e + f = 100.

As a method for laminating these Fe-Al-Si magnetic thin films (hereinafter referred to as main sendust films) and nitrogen-containing Fe-Al-Si magnetic thin films (hereinafter referred to as intermediate films), The sputtering in the argon gas atmosphere and the reactive sputtering in the argon gas atmosphere containing nitrogen gas may be repeated. That is, for example, first, a Fe—Al—Si magnetic material is sputtered on a substrate in an Ar + N ₂ gas atmosphere mixed so that the nitrogen content in the film is 0.005 to 4 wt%, and the specified film is formed. When the thickness is reached, the atmosphere gas is replaced with argon and sputtering is continued. At this time, for example, when the shutter is closed and the deposition by sputtering is interrupted, the columnar crystal division of the produced film becomes clear, but the sputtering may not be interrupted. This operation is continuously repeated a desired number of times to form a laminated film.

In the above laminated film, the thickness of the intermediate film is 30 to 2000Å
When the film thickness is less than 30Å, the effect of stacking does not appear due to the diffusion of nitrogen, and when it exceeds 2000Å, the magnetic coupling between the main sendust film and the intermediate film is weak and the improvement of the magnetic properties becomes insufficient. On the other hand, the thickness of the main sendust film is 1
The thickness is preferably in the range of 00Å to 5 μm, and if the film thickness is less than 100Å, the effect is poor, and conversely, if the film thickness exceeds 5 μm, the adhesion decreases. However, by adding a base film such as Cr to improve adhesion, the film thickness is 30 μm.
It becomes possible.

Further, as the number of stacked main sendust films and intermediate films,
One or more layers, hundreds or thousands of layers are possible, but generally several tens of layers are feasible.

[Action]

Fe-A containing nitrogen in the Fe-Al-Si magnetic thin film
By forming a laminated structure in which the 1-Si magnetic thin film is interposed as an intermediate film, the columnar growth observed in the Fe-Al-Si magnetic thin film is divided and relaxed, and the strain accumulated in the film is dispersed. At the same time, beneficial magnetic coupling between the Fe—Al—Si magnetic thin film and the nitrogen-containing Fe—Al—Si magnetic thin film is added, the coercive force is decreased, and the magnetic permeability is increased.

〔Example〕

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples.

Example 1. Using a Fe ₈₂ Al ₇ Si ₁₁ alloy (composition is a weight ratio) as a target, sputtering was performed in an argon gas atmosphere and an argon gas atmosphere containing a nitrogen gas in accordance with the following sputtering conditions by a two-way sputtering apparatus. As shown in the figure, disk-shaped crystallized glass substrate
(1) Fe-Al-Si magnetic thin film containing nitrogen on top
Five layers (2) and Fe-Al-Si magnetic thin film (3) were respectively laminated, and then heat-treated at 550 ° C for 1 hour to obtain a soft magnetic thin film. The total thickness of this soft magnetic thin film is 5μ.
m, and the thickness of the magnetic thin film (2a) deposited on the bottom layer is 50
It was 0Å.

Sputtering condition RF power 100W Target-substrate distance 30mm Substrate temperature -20 ° C (water cooling) Ultimate vacuum 3 × 10 ^-6 Torr Gas pressure 4 × 10 ^-3 Torr Magnetic thin film (2b) to be an intermediate layer according to the above sputtering conditions The film thickness was changed as shown in Table 1 to form a soft magnetic thin film. The coercive force Hc of each of the obtained soft magnetic thin films and the magnetic permeability μ at 1 MHz were measured. The results are shown in Table 1.

In addition, the above characteristics are the horizontal film and the substrate obtained by sputtering the substrate (1) and the target arranged horizontally.
(1) and the target were arranged obliquely, and the oblique film obtained by sputtering was measured. Further, for comparison, the same measurement was performed for a single layer of Fe—Al—Si magnetic thin film.

From Table 1, the coercive force Hc and the magnetic permeability μ are improved by stacking. For example, regarding the magnetic permeability μ at 1 MHz, in the horizontal film, it becomes the maximum when the thickness of the intermediate layer is 50 Å, and the oblique film has a maximum value. Then, it is understood that when the middle layer is 100 to 500 Å, it shows the maximum value.

Example 2. According to the same method as in Example 1, the thickness of the intermediate layer is set to 50.
A soft magnetic thin film composed of a horizontal film and an oblique film was prepared by setting 0Å and the total film thickness to 5 μm, and changing the number of layers as shown in Table 2. The coercive force Hc and the magnetic permeability μ at 1 MHz were measured for each of the obtained soft magnetic thin films.
The results are shown in Table 2.

It can be seen from Table 2 that the coercive force Hc and the magnetic permeability μ are improved in each soft magnetic thin film regardless of the number of stacked layers.

〔The invention's effect〕

As is clear from the above description, the soft magnetic thin film of the present invention is a Fe-Al-Si magnetic thin film and an Fe-containing Ni-containing magnetic thin film.
Since it has a laminated structure of Al—Si magnetic thin films, the coercive force is extremely small, the magnetic permeability is significantly improved, and good soft magnetic characteristics are obtained. In the soft magnetic thin film of the present invention, Fe-Al- containing nitrogen in the intermediate film.
Since the Si magnetic thin film is used, the saturation magnetic flux density, the specific resistance and the film hardness can be improved.

further. Fe-Al-Si containing nitrogen which is an intermediate film
The reactive sputtering method as a method of creating a magnetic thin film is
Since only the operation of substituting the atmospheric gas during sputtering is sufficient, it is easy to form a multilayer film.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of an essential part showing the configuration of an embodiment of a soft magnetic thin film according to the present invention. 2 ... Fe-Al-Si magnetic thin film containing nitrogen 3 ... Fe-Al-Si magnetic thin film

Claims (1)

[Claims] 1. A composition containing Fe, Al, and Si as main components and having Al and Si composition ranges of 2 to 10% by weight Al and 4 to, respectively.
Magnetic thin film of 15 wt% Si, Fe, Al, Si as the main components and the composition ranges of Al and Si are 2 to 10 wt% Al and 4 to 15 wt% S, respectively.
i, further comprising a magnetic thin film containing 0.005 to 4% by weight of nitrogen, the soft magnetic thin film.