JPS6235604A - Magnetically soft thin film - Google Patents

Abstract

PURPOSE:To contrive accomplishment of the state of low magnetic coercive force and the high degree of permeability which can not be attained in a single layer film by a method wherein an Fe-Al-Si magnetic thin film and an Fe-Al-Si magnetic thin film containing nitrogen are alternately laminated. CONSTITUTION:A magnetic thin film 3, containing Fe-Al-Si as the main component and having the compositional range of Al of 2-10wt% and Si of 4-15wt%, and a magnetic thin film 2 containing Fe, Al and Si as the main component and having the compositional range of Al of 2-10wt%, Si of 4-15wt% and nitrogen of 0.005-4wt%, are laminated on a substrate 1. The compositional range of Al content of 2-10wt%, Si content of 4-15wt%, and Fe for the remaining wt% is considered suitable for the Fe-Al-Si magnetic thin film 3 containing no nitrogen. As a result, the magnetic coercive force of the title soft magnetic thin film can be attenuated, and its permeability can be improved sharply.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soft magnetic thin film used as a core material of a magnetic head, and particularly to a soft magnetic thin film made of Fe.

Magnetic properties of a soft magnetic thin film mainly composed of AA and Si [Summary of the Invention] The present invention provides a soft magnetic thin film made of an Fe-Al-3i alloy material containing a Fe-A6-3t magnetic thin film and nitrogen. Fe-A
By alternately laminating l-3i magnetic thin films, it is possible to achieve low coercive force and high magnetic permeability, which cannot be achieved with a single layer film.

[Conventional technology]

For example, in magnetic recording and reproducing devices such as VTRs (video tape recorders), the recording signal density and frequency are increasing, and in response to this higher density recording, magnetic powder is being used as a magnetic recording medium. So-called metal tapes using powder of ferromagnetic metals such as Fe, Co, and Ni, and so-called vapor-deposited tapes in which ferromagnetic metal materials are deposited on a base film using methods such as vapor deposition, are being put into practical use. .

Since this type of magnetic recording medium has a high coercive force, the head material of the magnetic head used for recording and reproduction is required to have a high saturation magnetic flux density.

For example, ferrite materials, which are conventionally widely used as head materials, have a low saturation magnetic flux density and cannot cope with this increase in coercive force.

Conventionally, in order to support these high coercive force magnetic recording media, soft magnetic thin films with high saturation magnetic flux density are deposited on non-magnetic substrates such as ceramics or magnetic substrates such as ferrite, and these soft magnetic thin films are bonded to each other. Composite magnetic heads in which a magnetic gap is formed by abutting magnetic heads, and thin film magnetic heads in which soft magnetic thin films or conductive thin films are stacked in a multilayer structure with an insulating film interposed therebetween have been proposed.

As a soft magnetic thin film used in the above-mentioned composite type magnetic head or thin film magnetic head, a Fe-All-3t based magnetic thin film which is thermally stable and has a high saturation magnetic flux density is known.

By the way, F produced by sputtering method is usually
e-All-3i magnetic thin films have large anisotropy and internal stress within the film due to phase transition and columnar growth during film formation, and differences in thermal expansion with the underlying substrate, resulting in poor soft magnetic properties. inhibited. For example, Fe formed by sputtering method
- In the case of the All-3i magnetic thin film, its coercive force is nearly larger than that of the bulk. In particular, in a film sputtered from an oblique direction, the formation of a columnar structure due to the oblique incidence effect is significant, so that the magnetic properties are significantly deteriorated.

If the coercive force is large in this way, there is a risk that the Fe-Aj2-3i magnetic thin film, which is the core material, may become magnetized when a large magnetic field is applied to record on a magnetic recording medium such as a metal tape. be. 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 this coercive force.

A conventional method for improving the coercive force of the soft magnetic thin film is to laminate a magnetic layer and a nonmagnetic layer.

However, even with the above-mentioned soft magnetic film in which a magnetic layer and a non-magnetic layer are laminated, there is a limit to the suppression of coercive force.
Since completely different materials are laminated, the lamination method is also complicated.

[Problem that the invention seeks to solve]

As is clear from the description of the prior art described above, further improvements in coercive force, magnetic permeability, etc. are desired in soft magnetic thin films having high saturation magnetic flux density.

In view of this situation, the present invention has a very small coercive force,
The object is to provide a soft magnetic thin film having high magnetic permeability.

Means for Solving Problem C] As a result of intensive research, the present inventors determined that the above-mentioned objective could not be achieved.
The present invention was completed by discovering that laminating e-A/-3t based magnetic thin films is effective in suppressing coercive force and improving magnetic permeability. The above magnetic thin film has a composition range of Al and Si of 2 to 10 wt%/l and 4 to 15 wt% Si, respectively, and a composition range of F of 2 to 10 wt%/M, respectively! , 4-15
It is characterized by laminating a magnetic thin film containing 5% to 4% by weight of St and further 5 to 4% by weight of O, OO and nitrogen.

In the present invention, Fe-A7! does not contain nitrogen! -3t
The composition range of Fe, An, and Si contained in the system magnetic thin film is preferably such that the content of All is 2 to 10% by weight, the content of Si is 4 to 15% by weight, and the balance is Fe.

That is, the above Fe-Alt-3t based magnetic thin film was subjected to Fee A1. b S 1c (a, b, c represent the weight ratio of each component), the composition range is 70≦a≦95 2≦b≦lO 4≦C≦15 a+b+c=100 desirable. If the amount of Aff or Si is too small or too large, the magnetic properties will deteriorate, and it is also possible to replace a part of the Fe with at least one of Co or Ni.

By replacing a portion of the Fe with 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 amount of Co substituted is preferably in the range of 0 to 60% by weight based on Fe.

Similarly, by replacing part of the Fe with Ni,
Magnetic permeability can be kept high without reducing saturation magnetic flux density. The amount of Ni substituted is preferably in the range of 0 to 40% by weight based on Fe.

Furthermore, the above-mentioned Fe-A7! Various elements may be added to the -3t magnetic thin film as additives in order to improve corrosion resistance and wear resistance. Elements used as the additives include Sc, Y, La, and Ce.

Ma group elements including lanthanum series elements such as Nd and Gd, T
■A group elements such as i, Zr, Hf, V, Nb.

Va group elements such as Ta, Vla group elements such as Cr, Mo, and W, ■a group elements such as Mn, Tc, and Re, and Cu.

Group Ib elements such as Ag and Au, Qa, In, and Ge.

Examples include Sn and Sb. One or a combination of two or more of these additives is added in an amount of 0 to 10% by weight. That is, if the above additive is T, Fe-A! -3
The t-based magnetic thin film is F ea A Ah S 1 c Ta (a, b, c,
d represents the weight ratio of each component. ), it is desirable that the composition range satisfies the following: 65≦a≦95 2≦b≦10 4≦C≦15 0≦d≦10 a+b+c+d=100. The amount of the above additive added is 10
If the content exceeds % by weight, there is a risk that the magnetic properties will be deteriorated.

Alternatively, Ru, Rh, Pd as the above additives.

One or more platinum group elements such as Qs, Ir, and Pt may be added. In this case, the amount of the platinum group element added is 40
It is preferably less than % by weight.

If the amount added exceeds 40% by weight, there is a risk that the magnetic properties will deteriorate.

Furthermore, it is also possible to add both the above-mentioned Ma group element and IVaVa group element additives and the above-mentioned platinum group element.

In this case, the composition range is as follows: I [Ia group elements, r
Additives such as Va group elements are T, the platinum group elements are P,
Fe-Al! , -3i-based magnetic thin film as Fem Alb S Ic T4 P@(
a, b, c, d, and e represent the weight ratio of each component. ), it is preferable that the composition range satisfies the following: 55≦a≦95 2≦b≦10 4≦C≦15 0≦d≦10 0≦e≦40 a+b+c+d+e=100 Rh,
When Pd is used, d+e≦20. The above-mentioned platinum group elements include platinum group elements of the 6th period, namely Os, Ir, and P.
When using t, it is desirable that d+e≦40. If additives exceeding the above range are added, there is a risk that the magnetic properties will deteriorate.

On the other hand, nitrogen-containing Fe-
An! -AN contained in the 3i-based magnetic 11 film.

The composition range of Si and other additives is as follows:
e-A7! Although it is similar to the -3i magnetic thin film, it is necessary to additionally contain nitrogen in an amount of 5 to 4% by weight of O, OO.

Therefore, this nitrogen-containing magnetic thin film is F eh
When A11b S jc Nt (a, b, c, f represent the weight ratio of each component), the composition range is 70≦a≦95 2≦b≦10 4≦C≦15 2+b+c+f=100 , F ex Al! bS! c Ta Nt(a,
b, c, d, f represent the weight ratio of each component, and T represents an additive. ), the composition range is 65≦a≦95 2≦b≦10 4≦C≦15 0≦d≦10 0.005≦f≦4 a+b+c+a+f=100 Furthermore, Fe, AffbS ic T, P, Nf (a, b, c,
d, e, f represent the weight ratio of each component, T represents an additive, P represents a platinum group element, respectively), the composition range is 55≦a≦95 2≦b≦10 4≦C ≦15 0≦d≦10 0≦e≦40 0.005≦f≦4 a+b+c+d+e+f=100.

These Fe-A6-3t magnetic thin films (hereinafter referred to as main sendust films) and Fe-A7! containing nitrogen! -Si-based magnetic thin film (hereinafter referred to as intermediate film) can be laminated by repeating sputtering in a normal argon gas atmosphere and reactive sputtering in an argon gas atmosphere containing nitrogen gas. . That is, for example, first, Ar+N is mixed onto a substrate so that the nitrogen content in the film is 0.005 to 4% by weight, and then F is mixed in a gas atmosphere.
e-A7! -3i-based magnetic material is sputtered, and when a specified film thickness is reached, the atmospheric gas is replaced with argon and sputtering is continued. At this time, for example, if the shutter is closed and sputtering adhesion is interrupted, the columnar crystal divisions in the produced film will become clearer, but it is not necessary to interrupt sputtering. 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 preferably 30 to 2,000. If the film thickness is less than 30, the effect of lamination will not appear due to nitrogen diffusion, and if it exceeds 2,000, the magnetic field between the main sendust film and the intermediate film The magnetic coupling is weak and the improvement in magnetic properties is insufficient.

On the other hand, the thickness of the main sendust film is preferably in the range of 100 to 5 μm; if the thickness is less than 100 μm, the effect will be poor, and if the thickness exceeds 5 μm, the adhesion will decrease. However, by adding a base film such as Cr to improve adhesion, the film thickness can be increased to 30 μm.

In addition, the number of laminated layers of the main Sendust film and intermediate film is as follows:
Although it is possible to have one or more layers, hundreds of layers, or even several thousand layers, it is generally practical to have up to several tens of layers. .

[Effect]

By creating a laminated structure in which the Fe-Al1-3t magnetic thin film contains nitrogen, the columnar growth observed in the Fe-An-3i magnetic thin film is disrupted and relaxed, and the strain accumulated in the film is dispersed. At the same time, beneficial magnetic coupling between the Fe-Al-3i magnetic thin film and the nitrogen-containing Fe-Al2-3i magnetic thin film is also added, and the coercive force decreases and the magnetic permeability increases.

〔Example〕

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

Example 1゜F eszA Z? Using S i 11 alloy (composition by weight) as a target, sputtering was performed in an argon gas atmosphere and in an argon gas atmosphere containing nitrogen gas using a binary sputtering device according to the following subafuta conditions, as shown in Fig. 1. As shown, Aj! containing nitrogen on a disk-shaped crystallized glass substrate (1). - After laminating five layers of each 3i-based magnetic thin film (3),
A soft magnetic thin film was obtained by heat treatment for a period of time. The thickness of the entire soft magnetic thin film was 5 μm, and the thickness of the magnetic thin film (2a) deposited as the bottom layer was 500.

Sputtering conditions RF power: 100 W Target-substrate distance: 301 m Substrate temperature: ~20°C (water cooling) Ultimate vacuum: 3 x 10-” Torr Gas pressure
4 x 10-'Torr According to the above sputtering conditions, the thickness of the magnetic thin film (2b) serving as the intermediate layer was changed as shown in Table 1, and a soft magnetic thin film was formed. The coercive force (c) and magnetic permeability μ at IMHz of each of the obtained soft magnetic thin films were measured. The results are shown in Table 1.

The above characteristics apply to a horizontal film obtained by performing sputtering with the substrate (1) and target arranged horizontally, and an oblique film obtained by performing sputtering with the substrate (1) and target arranged diagonally. , were measured respectively. For comparison, measurements were also conducted on a single Fe-Aj2-3i magnetic thin film.

Table 1 From this Table 1, it can be seen that both coercive force HC1 and magnetic permeability μ are improved by lamination.For example, looking at the magnetic permeability μ in IM)Iz, when the thickness of the intermediate layer is 50 in the horizontal film, It can be seen that in the diagonal film, the maximum value is reached when the middle class is 100 to 500 people.

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

Table 2 From Table 2, it can be seen that the coercive force He and magnetic permeability μ are improved in each soft magnetic thin film, regardless of the number of laminated layers.

〔Effect of the invention〕

As is clear from the above description, the soft magnetic thin film of the present invention is Fe-Aj! -3i magnetic thin film and nitrogen-containing Fe
Since it has a laminated structure of one -Al-5i magnetic film, the coercive force is extremely small, the magnetic permeability is greatly improved, and good soft magnetic properties are obtained. In addition, in the soft magnetic thin film of the present invention, Fe-A7 containing nitrogen in the intermediate film
! Since a -3t magnetic thin film is used, it is possible to improve saturation magnetic flux density, specific resistance, and film hardness.

Furthermore, Fe-Al-3i containing nitrogen, which is an intermediate film,
The reactive sputtering method is a method for creating magnetic thin films.
Multilayer film formation is easy because the only operation required is to replace the atmospheric gas during sputtering.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a main part showing the structure of an embodiment of a soft magnetic thin film according to the present invention. 2...Fe-A7 containing nitrogen! -3i magnetic thin film

Claims (1)

[Claims] Fe, Al, and Si are the main components, and the composition ranges of Al and Si are 2 to 10% by weight, Al and 4 to 15% by weight, respectively.
A magnetic thin film that is Si, and the main components are Fe, Al, and Si, and the composition ranges of Al and Si are 2 to 10% by weight Al and 4 to 15% by weight, respectively.
A soft magnetic thin film characterized by laminating a magnetic thin film made of Si and further containing 0.005 to 4% by weight of nitrogen.