JPS62104109A - Soft magnetic thin film - Google Patents

Abstract

PURPOSE:To obtain the soft magnetic thin film having high saturation magnetic flux density Bs and high permeability mu and especially sperior abrasion resistance property by specifying the composition of a soft magnetic thin film formed of an alloy of Fe-Co-Si-Al group added with Cr. CONSTITUTION:A magnetic thin film mainly composed of Fe, Co, Si and Al is added with chrominum Cr. Namely, Fe, Co, Si and Alare main components and the composition is as 5-15atm% Co, 6-17atm% Si, 2-13atm% Al, 0.5-7atm% N, and Fe as the remainder. If the content of Co is beyond the range of 5-15atm%, an increase of a coersive force or a decline of permeability can be observed. Also, 6-17atm% of Si and 2-13atm% of Al are necessary. If the contents of Si and Al are beyond such ranges, for example, a coersive force increases so that they can not be used as a core material of a magnetic head, and at the same time, a lowering of a saturation magnetic flux density or permeability can be observed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soft magnetic thin film suitable for use in, for example, a thin film magnetic head.

(Summary of the Invention) The present invention provides a Fe-Co-3i-Affi alloy with Cr.
By specifying its composition, a soft magnetic thin film having a high saturation magnetic flux density Bs, a high magnetic permeability μ, and particularly excellent wear resistance can be obtained.

[Conventional technology]

2. Description of the Related Art In various magnetic recording and reproducing devices, demands for higher density recording and higher frequency are increasing, and in response to this, magnetic recording media with high saturation magnetization and high coercive force are used. As this type of magnetic recording medium, there are so-called metal tapes using ferromagnetic total bending powder such as Fe, Co, and Ni, and so-called vapor-deposited tapes made of ferromagnetic metal materials coated on a base film. It has come to the point where

Along with this, magnetic heads for this type of magnetic recording medium are required to be made of head materials with high saturation magnetic flux density and high magnetic permeability, and due to the demand for high-density recording,
The relative speed between the magnetic medium and the magnetic head is becoming faster, and as a result, the head material has as much wear resistance as possible (excellent corrosion resistance, etc.) as well as chemical properties. It is required to be stable and have excellent mechanical properties.

As this magnetic material, it is considered to use an amorphous magnetic alloy material that has high magnetic permeability and a high saturation magnetic flux density Bs, but this amorphous magnetic alloy material has a drawback in heat resistance. However, due to long-term heating and thermal cycling, the magnetic permeability deteriorates significantly and the regeneration efficiency deteriorates. In particular, since there is a high possibility of crystallization, it is impossible to apply temperatures of 500°C or higher for a long time.For this reason, in the manufacturing process of magnetic heads, for example, 500°C
There are problems such as the fact that it is undesirable to use a process that requires treatment at a temperature higher than °C.

Under these circumstances, research into soft magnetic materials that exhibit even better soft magnetic properties has progressed.
In 0 years), Fe containing Fe, Co, and Si as main components
It has been reported that Co-5i alloy materials exhibit good soft magnetic properties.

However, this Fe-Co-5i alloy material is extremely brittle and has poor practical use, and there are problems in using it as it is as a core material for a magnetic head.

On the other hand, with high-density recording, there is a need to narrow the recording track width, and therefore the track width of the working magnetic gap in magnetic heads. Thin film magnetic heads using thin film technology, in which a soft magnetic core is formed by adhering a soft magnetic thin film onto a non-magnetic or magnetic substrate, are becoming increasingly popular. As this type of soft magnetic thin film, a Sendust alloy thin film containing Fe, ^/, and St as main components is attracting attention.

This Sendust alloy thin film has a high saturation magnetic flux density Os and relatively high hardness, so it can be used for magnetic recording media with high residual magnetic flux density, such as the metal tape mentioned above. be.

However, although this sendust alloy thin film has relatively high hardness, it has inferior wear resistance and corrosion resistance compared to, for example, ferrite materials.

(Problems to be Solved by the Invention) The present invention aims to improve the above-mentioned problems, and has a structure in which the coercive force 11c is small, the magnetostriction λS is almost zero, and the saturation magnetic flux density Bs and the transmittance μ are not reduced. The object of the present invention is to provide a soft magnetic thin film that has small magnetic anisotropy, excellent magnetic properties, and particularly excellent wear resistance.

[Means for solving problems]

In the present invention, chromium Cr is added to a magnetic thin film whose main components are re, Co, Si, and Al.

That is, the present invention has Fe, Co, St, and A1 as main components, and the composition is such that Co is 5 to 15 atomic %, Si is
is 6 to 17 at%, Al is 2 to 13 at%, N is 0.5
~7 atomic %, the balance being Pe.

The thickness of the soft magnetic thin film according to the present invention having the above composition is preferably 10 Å or more and 1 ms or less, and more preferably 10 Å or more and 100 μm or less.

[Effect]

As mentioned above, the soft magnetic thin film according to the present invention is made of Fe.

The main components are Co, Si, Al, and Cr, and by adding Al, a soft magnetic material with high magnetic permeability and low coercive force and magnetostriction can be obtained compared to Fe-Co-5i-based soft magnetic materials. However, in addition, in the present invention, C
It is characterized by containing r, which particularly improves wear resistance.

According to experiments conducted by the present inventors, when the Co content is outside the range of 5 to 15 at %, an increase in coercive force and a decrease in magnetic permeability are observed.

Also, Si, Aj! For each, Si is 6~
The content of Al should be 17 at% and 2 to 13 at%.

This is because if the content of Si and Al is outside these ranges, for example, the coercive force becomes too large to be used as a core material for a magnetic head, and at the same time, a decrease in saturation magnetic flux density and a decrease in magnetic permeability are observed. by. On the other hand, if the above-mentioned range is used, low coercive force, high saturation magnetic flux density, high magnetic permeability, and zero magnetostriction can be achieved.

Regarding Cr, if the Cr content is less than 5 at%, high wear resistance cannot be obtained, for example, it will be lower than that of Sendust, and if it exceeds 15 at%, magnetic properties such as saturation magnetic flux density will deteriorate. do.

〔Example〕

Example 1 A pot made of pure iron with a purity of 99.9% or more, electrolytic cobalt, chromium, aluminum, and silicon with a purity of 99.999% or more, each weighed and aluminized using a high-frequency induction heating furnace. Melt in an argon gas and
A target base material of 5a+m was cast.

Both sides of this base material were ground with a surface grinder to a thickness of 5+u.
A + sputtering target was prepared.

Using this target, sputtering was performed on a crystallized glass substrate to a thickness of 2 μm using a planar magnetron type high-frequency sputtering device. The conditions for this sputtering were as follows: Ultimate gas pressure 6. OX 10-' Torr
Substrate temperature Ar gas pressure without heating? , OX 1O-3Tor
r Preliminary sputtering 1 hour Sputtering time Approximately 1 hour.

The substrate on which the sputtered thin film was formed in this way was
After vacuum annealing at .degree. C. for 1 hour, the magnetic properties of the thin film, ie, the saturation magnetic flux density Bs, the coercive force Hc, and the magnetic permeability μeff at a frequency of 5 Mflz, were measured by changing the film composition. Furthermore, the amount of wear was measured for each composition. The results are shown in FIG.

Here, the amount of wear was measured by preparing a dummy head (11) for measuring the amount of wear, as shown in FIG.

This head (υ is @W is 3.0IIII, thickness t is 0
．． A cylindrical surface facing the magnetic medium is formed at the front with a thickness of 5 mm, the thin film to be measured (2) is adhered to this surface, and the head (
11 is placed on the plywood of a rotating magnetic head drum for a 1-inch VTR, and protrudes by 80μ±5μm from the drum surface.
It was connected to an Ff320g type magnetic medium. in this case,
The membrane surface (2) was examined under a microscope (magnification 4) every 5 hours of tape running time.
00 times), and the amount of wear was measured based on the distance from the marker (3) attached to a predetermined position on the head (1). In addition, the sputtering of the film to be measured onto this dummy head is performed at the following gas pressure: 6. Ox lO = Torr substrate temperature 300-400℃ Ar gas pressure
? , OX 10"' Torr preliminary sputtering 1 hour sputtering time 4 to 5 hours. Then, for each composition, measurements were made using a dummy head of 6 (lI), and the average wear amount was calculated as shown in Figure 1. It was shown to.

As can be seen from Figure 1, Cr-added Fe-Co-Al
The soft magnetic thin film of the present invention based on the -5i system can improve the amount of wear per hour without deteriorating the magnetic properties,
This is sufficiently smaller than Sendust's 0.12 μs/hour.

Furthermore, in the soft magnetic Wllil according to the present invention described above,
Furthermore, various elements may be added as additives to improve corrosion resistance, wear resistance, and other various properties.

The element used as this additive is Ti.

IVa group elements such as Zr and Hf, Va group elements such as V, Nb and Ta, Vla group elements such as Mo and W, ■a group elements such as Mn, and platinum group elements of the fifth period as platinum group elements, Namely, these additives include Ru, Rh, Rd, 6th period platinum group elements such as Os, Ir, PL, etc., and one or more of these additives may be used in combination to add to the magnetic thin film. Te θ ~ 1 off
It can be added in an amount of i%.

〔Effect of the invention〕

As described above, the soft magnetic thin film according to the present invention has high magnetic permeability and excellent wear resistance without reducing the saturation magnetic flux density or increasing the coercive force, and also has thermal resistance similar to that of an amorphous magnetic thin film. Since it is possible to obtain a soft magnetic thin film with excellent heat resistance and no instability, it can be used, for example, as a WIliil magnetic core of a \i-film magnetic head for high-density recording, and its benefits are extremely large.

[Brief explanation of drawings]

FIG. 1 is a table showing the composition of the soft magnetic thin film and the measurement results of each characteristic, and FIG. 2 is an enlarged perspective view of a dummy head for measuring wear amount. (II is the dummy head, and (2) is the thin film to be measured. Procedural amendment December 9, 1985 Patent office public official U 1 ¥ Road Department 1 2) 51'
l Table 2 no.q
Sato Showa GO Patent Application No. 244563 2
, Title of invention Soft magnetic thin film: 3. ? +! i if:, someone who does! Relationship with IS case Patent applicant address: 6-7-35, Kitashinyo, Tokyo Parts Store Name: 4ts
: (21B) Sony Corporation 1 (Representative Director: Ohga
Norio 4, Agent address: 8-1 Nishi-Shinjuku I-chome, Shinjuku-ku, Tokyo 03-
343-5821 (l Ri (Shinjuku Building) [j, number of inventions increased by amendment + 1) In the specification, page 5 "1 line IN is 0.5" is I-
Cr is 0.5”. (2) Same, page 6, line 15, 1cr is 5 atomic%” is 1-
Cr content is 0.5 atomic%.'' (3) Same, @page 6, lines 16-17 [For example, it becomes lower] is deleted. (4) Same, page 9, line 10 to line 11 E are calculated...
Correct "It is being measured" to "It is being measured." (5) In the drawings, correct Figure 1 as shown in the attached sheet. that's all

Claims (1)

[Claims] Co: 5 to 15 at%, Si: 6 to 17 at%, Al
is 2 to 13 at%, Cr is 0.5 to 7 at%, and the balance is Fe.
A soft magnetic thin film characterized by having a composition.