JPS62263945A - Soft-magnetic alloy - Google Patents

Abstract

PURPOSE:To obtain a soft-magnetic alloy combining low magnetostriction with high saturation magnetic flux density and excellent in thermal stability, corrosion resistance, and wear resistance, by providing a Co-Zr-Nb-Ta alloy having a specific composition. CONSTITUTION:The soft-magnetic alloy has a composition consisting of, by atom, 3-6% Zr, 1-4% Nb, 6-9% Ta, and the balance Co with inevitable impurities. In the above composition, the proportion of Co contained as the principal component of this soft-magnetic alloy is regulated to 84-87atom% (particularly 85-86atom%) because, when its proportion is too high, crystallization temp. becomes too low and, on the other hand, when its proportion is too low, saturation magnetic flux density becomes too low.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a soft magnetic alloy that can be used as a soft magnetic underlayer in a magnetic head such as a thin film magnetic head or a perpendicular magnetic head, or a perpendicular magnetic recording medium.

[Prior art and its problems]

Conventionally, permalloy made of iron-nickel system and sendust alloy made of iron-silicon-aluminum system have been proposed as soft magnetic alloys with high magnetic permeability. However, when trying to use these Permalloy and Sendust alloys as core materials for magnetic heads, for example, since Permalloy and Centus l-q gold have low electrical resistance, they must be made into thin strips to reduce eddy current loss. Or,
However, in order to obtain sufficient magnetic permeability, the thickness must be 104 m or less. However, it is extremely difficult to process this kind of thin ribbon.
In addition, when thin film technology such as sputtering is applied, permalloy and Cenrus 1~alloy are both crystalline, so unless the thermal expansion coefficients of the substrates are made approximately the same, film peeling or substrate destruction may occur. There is. Therefore, research and development of soft magnetic alloys to replace these Permalloy and Centus 1 alloys has been actively conducted, and as a result of such research and development, Co -Zr-based thin film alloys have been proposed. That is, this Co--Zr based thin film alloy has a high saturation magnetic flux density and high magnetic permeability, and is also known to have good adhesion to substrates because it is amorphous. Although this Co-Zr thin film alloy has a low magnetic permeability at the time of thin film formation, it can be made to have a high magnetic permeability by performing heat treatment at a temperature higher than the Curie temperature Tc. . However, if the heat treatment temperature TW for improving magnetic permeability exceeds the crystallization temperature Tx of amorph 7.s, a significant deterioration of properties will occur due to crystallization. Must be low;
This heat treatment temperature TW is generally in the range of about 300 to 500°C. When this Co-Zr thin film a gold is applied to a magnetic head, the temperature is not less than 500°C in the crow molding process in the magnetic head manufacturing process.
Since the film is exposed to temperatures higher than the crystallization temperature Tx, conventional Co-Zr based Wl film alloys have not been satisfactory.

[Disclosure of inventiveness]

While proceeding with research on the above-mentioned problems, the present inventor discovered that a soft magnetic material with low magnetostriction, high saturation magnetic flux density, extremely strong thermal stability, corrosion resistance, and abrasion resistance. Amorphous h with Co as 1
As I continued my research, I found that Zr or about 3 to 6
Atomic % and "old" is about 1~/1 cool? 5; and Ta is about O
〜91G [Complete; o, so &',) Other downtown area impurities are removed and the remaining CO is Co - Z r - N b 'r
A-series gold has high saturation magnetic flux density and high magnetic permeability,
In addition, it has strong thermal stability that can withstand the use of low-melting glass used in processing magnetic heads, etc., and low magnetostriction that can withstand use under stress in contact with substrates. It has been found that not only the crystallization temperature Tx is higher, but also the crystallization temperature Tx is much higher than the softening temperature of low melting point glass. Here, the reason why the Ta content is set at about 6 to 0 at. This is because the effect of increasing the Ta content is small, and conversely, even if the Ta content is high, the effect of increasing the crystallization temperature Tx is weak, and the effect of increasing magnetic permeability is small. It is even more preferable that the content of Ta is about 7 to 8.5% of original T. Also, the reason why the Zr content is about 3 to 6 atomic % is because if the Zr content is too small or if the Zr content is too large, the magnetostriction will increase and the magnetic permeability will decrease. This is because it becomes lower. And the content ratio of this Zr is about 4
It is even more preferable that the content be 5 atomic %. Also, the reason why the Nb content is set at about 1 to 4 atomic % is because if the Nb content is too small, the crystal temperature T
The effect of increasing x is weak, and the effect of increasing magnetic permeability is also small; conversely, if the content ratio of [old] becomes too large, the effect of increasing crystallization temperature Tx is weak, and the effect of increasing magnetic permeability is small. Although the effect is small, it is even more preferable that the content of this former) is about 1.5 to 3 atom %. Therefore, C is the main component of the soft magnetic alloy of the present invention. If the content ratio is too high, the crystallization temperature Tx will become too low, and conversely, if the content ratio is too low, the saturation magnetic flux density will become too low. It is desirable that the content is about 84 to 87 atomic percent, and even more preferably about 85 to 86 atoms 96
It is preferable that the

【Example】

In order to form a Co-Zr-N1+-Ta alloy thin film,
Zr, Ta and Nb were deposited on a Co plate of 126 tn mφ as a tartant using a Macnetron sputtering device.
The final vacuum level was 10-77 orr, the Ar gas pressure was 1 mm Torr, the distance between Targetera 1 and the substrate was 110 mm, and the substrate was crystallized glass (PEG: 1100 mm). .10 Ill
m x 10 mm), board water cooling, input power 10
0QI11, sputter rate approximately 0.1μ+n/m
Macnetron sputtering was performed under the conditions of i.

[n thickness Coa5 Zr, N
b1o,, x Tax (numbers are atomic %) Do not form extra thin film. The Co-Zr-Nb-Ta alloy thin film obtained in this way was heat-treated in a rotating magnetic field heat treatment furnace at a magnetic field strength of 1000 oersted and a rotational speed of 2000 rpm for 60 minutes in vacuum to reduce the magnetic permeability. As a result of the recovery process, this effective magnetic permeability μ'5MHi is as shown in the graph in the drawing, and is sufficiently high. This effective magnetic permeability was determined by forming a film on a +44φ2 PEG3100 link, insulating the manifold L'NA, and making 20 turns of a wire with a diameter of φ0.08, and using a vector impedance meter. In addition, when measuring the saturation magnetic flux density, the higher the Co content, the higher it is, but in a case where the Co content is about 85 T-5゛6 as in this example, the ratio of other components is Even if it fluctuates, it does not change that much, it is about 8500 Gauss, and the saturation magnetic flux density is also high enough for practical use. Note that the saturation magnetic flux density is measured using a vibrating sample magnetometer (\7SM).
In addition, when the A lily temperature Tc and the crystallization temperature Tx were measured using lKOe excitation, they were not shown in the graph in the drawing, and the Ta content was approximately 6. ~9 atom% field 3, Tx>Tc, and crystal 1
A temperature of 1× is sufficiently high. Note that Tc and Tx are vibrating sample magnetometers (V S M
) was read from the temperature change in the magnetization amount d, and Tc was determined from molecular field approximation. [Effect] The soft magnetic 8-gold according to the present invention has It about '-1-(J h
C'T'/Ll, old) about 1-1 atoms ゛36, and Ta
It is made of approximately C (> 9) and residual Co including other unavoidable impurities, and has high saturation magnetic flux density and high magnetic permeability, as well as thermal stability and wear resistance. Excellent in sex,
And 1. (It has a low magnetostriction that can withstand use under plate bonding stress, and the crystallization temperature Tx can be significantly increased. Therefore, the manufacturing regulations for magnetic heads etc. using this soft magnetic alloy will be relaxed, and the magnetic There is an improvement in the quality of the head etc., and the production yield is also improved. ,・1 The explanatory drawing that fits the section of the drawing shows the effective transparency of the Magnetic coefficient μ' 511, ¥ J 1 temperature 1 ゛ (2 and crystal (L temperature Tx) shows the relationship with J'' 7. -8~

Claims (1)

[Claims] Zr about 3-6 at%, Nb about 1-4 at%, Ta
The remaining Co contains approximately 6 to 9 at% and other unavoidable impurities.
A soft magnetic alloy characterized by consisting of.