JPS6066309A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain a magnetic head which has high magnetization, low coercive force and high corrosion resistance and permits reproduction of a desired magnetization characteristic by forming at least a part of a magnetically permeable layer of a specific alloy. CONSTITUTION:A magnetic head is constructed by depositing a magnetic film 14 consisting of Co-Ta-Zr on a glass substrate S as a main magnetic pole 17 and protecting the same with a holer 18. The main magnetic pole for vertical magnetic recording is thus obtd. The Co-Ta-Zr alloy has high magnetization, low coercive force and high corrosion resistance and permits reproduction of a desired magnetization characteristic. The magnetic film 14 consisting of Co-Ta-Zr is formed on the opposed surfaces on the magnetic gap 20 side of a core material S consisting of ferrite, by which a magnetic head 27 for audio purpose is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Industrial Application Field The present invention relates to a magnetic head. 02. Prior Art Conventionally, magnetic recording media such as magnetic tapes and magnetic disks have been
It is widely used for recording various electrical signals such as video, audio, and digital. In a method that uses magnetization in the in-plane longitudinal direction of a magnetic layer (magnetic recording layer) formed on the base substrate, high density is being achieved by using new magnetic materials and new coating techniques. On the other hand, in recent years, with the increase in the density of magnetic recording, perpendicular magnetization recording methods that use magnetization in the thickness direction of the magnetic layer of a magnetic recording medium (so-called perpendicular magnetization) have recently been proposed (for example, , [Nikkei Electronics J August 7, 1978 issue A192] According to this recording method, as the recording wavelength becomes shorter, the demagnetizing field that acts on the residual magnetization in the medium decreases, which is favorable for increasing the density. This method is inherently suitable for high-density recording, and research is currently being conducted to put it into practical use.

The following two main physical properties are required for the magnetic head material, for example, the magnetic film (permeable layer) for the above-mentioned perpendicular magnetization and the thin film magnetic head.

(1), saturation magnetization (4πMs) is 10,000 Gauss
Must be at least s.

(2), magnetic permeability (μ 5000 or more, coercive force (Hc)
exhibits soft magnetism of several Oe or less.

Amorphous Co-Zr has been proposed as this type of head material (6th Japan Society of Applied Magnetics [Academic Lecture Abstracts J, November 1982, p. 39), 4πM8=14
．． 000 Gauss, pL -5000 Gauss
(at I MHz) and is said to exhibit good magnetic properties. In order to eliminate magnetic anisotropy, head materials generally have to undergo heat treatment (for example, 250°C for 160 minutes) after film formation, but the above-mentioned known Co-Zr head material has soft magnetic properties that can be improved by heat treatment. greatly affected.

That is, when this head material is subjected to heat treatment in a magnetic field, the magnetic anisotropy is fixed by the anisotropic magnetic field (in other words, H
It is necessary to control the anisotropic magnetic field to prevent this (increase in a), and for this purpose, heat treatment must be performed in a rotating magnetic field (for example, 2700e) or in a magnetic field in the direction of the hard magnetization axis.

Thanks to this heat treatment! l) Co--Zr head material exhibits high magnetic permeability and low coercive force, but the reproducibility of these sizes and directions is difficult. This is because the substrate and Co-
It is believed that the anisotropy due to residual stress between the Zr film and the Zr film is the main cause of the thermal instability of the magnetization characteristics. The object of the present invention is to provide a magnetic head having a head material that exhibits high magnetization, low coercive force, and high corrosion resistance, and can reproduce the required magnetization characteristics without the above-mentioned heat treatment.

4. Structure of the invention, that is, in the present invention, at least a part of the magnetically permeable layer is made of cobalt.
Tantalum-zirconium alloy (hereinafter referred to as Co-Ta-Zr)
It is written as 05, Embodiment Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows magnetic heads 16 and 17 used for perpendicular magnetic recording on a magnetic recording medium 15 such as a magnetic tape. Of these, the head 16 functions as an auxiliary magnetic pole, and the head 17 placed opposite thereto functions as a main magnetic pole.

What is characteristic here is that the main magnetic pole 17 has a structure in which a magnetic film 14 made of co-Ta-Zr is deposited on a glass substrate S, and this is protected by a holder 18 such as another glass plate. is that it is using .

Magnetic B! As will be clear from what will be described later, Co--Ta--Zr constituting X14 has a large saturation magnetization and can perform sufficient signal recording, while at the same time exhibiting the low coercive force (Hc) required for the head. Therefore, such a magnetic film 14
The performance of a head having this as a magnetically permeable layer is extremely good. Moreover, Co-Ta-Zr has good corrosion resistance.
This also contributes to improving head characteristics.

For example, in this perpendicular magnetic recording method, the auxiliary magnetic pole 16 is excited by a recording signal, and the medium 15 is
A magnetic field is generated to the side, and the seven lasoxes are concentrated in the in-plane direction toward the main magnetic pole 17, and magnetic recording corresponding to the main magnetic pole 17 is performed in the magnetic layer of the medium 15. For this purpose, the medium 15 has a perpendicular magnetization film (for example, Co--Cr) 23 laminated on a support 21 with a soft magnetic layer (for example, permalloy) 22 interposed therebetween.

FIG. 2 shows a magnetic head 27 for audio, for example, to which the present invention can be applied. In this head as well, Co-Ta-Z is applied to the opposing surface of the core material S made of ferrite, on the side where the magnetic gear is applied. A magnetic film 14 made of r is formed respectively. Note that the entire head is made of Co-Ta-Z.
The head may be covered with r. These C
Heads made of o-Ta-Zr are particularly suitable for high-density recording.

Further, the Co--Ta--Zr magnetic film 14 described above can also be formed on magnetic heads other than those described above (for example, thin film heads).

Next, Co--Ta--Zr constituting the magnetic film 14 will be described in detail.

First, CoTa-Zr (actually a ternary amorphous alloy) was deposited at an Ar pressure of 5 mTorr and a deposition rate of 45 to 70 A using an RF two-pole sputtering device (Fig. 6), which will be described later.
The film was formed under the following conditions: /min, substrate temperature 1()0°C or less.

The resulting Co-Ta-Zr film was subjected to compositional analysis by EPMA (electron probe microanalysis (also referred to as X-ray microanalysis)) and structural evaluation by X-ray diffraction, and its saturation magnetization (4πMs) was found to be V
Coercive force (Hc
) was measured using a hysteresis scope (10 KHy).

As a result, it was found that Co-Ta-Zrg has a composition range as shown in FIG. 3, and exhibits a composition ratio at which the saturation magnetostriction (λS) becomes zero. That is, the addition of zr significantly expands the composition range in which the film structure becomes an amorphous phase, and even in the composition where λS is zero, the Co concentration reaches 95 at % (ato
An amorphous state can be obtained up to mic%).

FIG. 4 shows the composition dependence of 4yrMs in the Co--Ta--Zr film. According to this, the maximum value of 4πMs obtained in the amorphous phase is about 1 for a film with a Co concentration of 95.2 at%.
There is 6K Gauss ″C.

In addition, regarding the compositional dependence of Hc in the Co-Ta-Zr film, it was confirmed that λS becomes zero near the composition where Hc takes the minimum value, and internal stress measurements show that the compressive stress is the minimum for that composition. It was found that the composition was consistent with the composition. The obtained H
It was confirmed that c was several Oe or less.

In addition, Co-Ta-Zr after film formation shows good magnetization characteristics even as it is as described above, but when heat treatment is applied as described above, Ha gradually decreases as the temperature rises.
This is thought to be due to relaxation of internal stress. If the temperature is further increased, Hc will increase in a film with a large Coa'lf degree, so the treatment temperature is preferably 350 to 400°C or less. On the other hand, it was also found that the crystallization temperature of the Co-Ta-Zr film was 480°C for Co95atS and 560°C for Co85at%, and that the crystallization temperature of the binary Co-Ta film also increased significantly.

Next, in the magnetic recording system shown in FIG. 1, the thickness of the magnetic film 14 of the main pole is 1 μm, the rank width is 500 μm, and various magnetic films (including Co-Ta-Zr according to the present invention and other known The reproduction output obtained using each magnetic head with a film made of Co-Zr or permalloy is
As shown in the figure. According to this, it is clear that the output characteristics are significantly improved by applying the magnetic film according to the present invention, clearly demonstrating the superiority of the present invention.

As mentioned above, the Co-Ta-Zr film according to the present invention has a 4π
M8 is large enough, HC is low, and magnetic heno is Co-T.
It has also been found that it can be made sufficiently small (preferably zero) by selecting the composition ratio of a-Zr.

Next, an apparatus for forming the Go-Ta-Zr film 14 described above in 1 will be explained.

The apparatus shown in FIG. 6 is an RF bipolar sputtering apparatus,
In the reaction tank 3o, a substrate S on a substrate holder 31 and a target T on a target holder 32 are arranged facing each other, and a high frequency voltage is applied to the holders 31 and 32 with ra, '5 Ic, and a high frequency power source 33. , sputtering is performed while introducing Ar gas 34 through the inlet 35.

The exhaust gas 36 is discharged through the outlet 37. As clearly shown in FIG. 7, the target T is configured as a composite target, and includes a VCTa chip 39 on a disk-shaped Co plate and a Z
r chips 4o are arranged in a radial positional relationship, and predetermined amounts of Co, Ta, and Zr are each knocked out by plasma during sputtering, and deposited on the substrate S as Co--Ta--Zr. The sputtering conditions in this case are, for example, Ar
Gas pressure = 20 mTorr.

The high frequency power may be 150 W, and the substrate temperature may be 100° C.

FIG. 8 shows a facing target sputtering apparatus different from the above.

In the drawing, 41 is a vacuum chamber, 42 is an exhaust system consisting of a vacuum pump etc. for evacuating the vacuum chamber 41, and 43 is an exhaust system that introduces a predetermined gas into the vacuum chamber 1 to raise the gas pressure to 10 to 10 Torr.
This is a gas introduction system set at approximately r.

The target electrode is attached to the target holder 44, C
A pair of targets T] and T2 made of o-Ta-Zr are arranged as opposed target electrodes in parallel with each other and separated from each other. A magnetic field is generated between these targets by magnetic field generating means (not shown). On the other hand, the substrate S on which the magnetic thin film is to be formed is held in the substrate holder ~ 45
is arranged vertically laterally between the opposing targets. In the sputtering apparatus configured in this way,
A magnetic field is formed in the direction perpendicular to the surfaces of T1 and T2, which face each other in parallel. The γ electrons emitted by the impact of the sputtering gas ions accelerated by the electric field on the target surface in the region between T1 and T2 are trapped in the space between the targets and moved toward the other opposing target.

The γ electrons that have moved to the other target surface are reflected at the cathode fall section nearby. In this way, the γ electrons repeatedly move back and forth between the targets TIT2 while being constrained by the magnetic field. During this reciprocating motion, the γ electrons collide with the neutral atmospheric gas to generate ions and electrons of the atmospheric gas, and these products promote the release of γ electrons from the target and the ionization of the atmospheric gas. .
Therefore, high-density plasma is formed in the space between T+ and T2, and the target material is sufficiently sputtered and deposited as a magnetic material on the side substrate S. .

Compared to other flying methods, this facing target sputtering device is capable of forming films at high deposition rates through high-speed sputtering, and the substrate is not directly exposed to plasma, allowing film formation at low substrate temperatures. This method is advantageous for forming a perpendicularly magnetized film. In addition, the incident energy of the magnetic film material that is ejected between the opposing targets by the Nokutsuta device onto the substrate is smaller than that of the normal Nokutsuta device, so the material can be deposited directionally in the desired direction. This makes it easier to create a film with a structure suitable for perpendicular magnetization recording.

The present invention has been described above as an example, but the above-mentioned example can be further modified based on the technical idea of Kihatsu Iy].

For example, the structure of the head and the method of forming the CoTa-Zr film 11 may be changed in various ways. The magnetic permeability of the head is Co-
It can also be formed with a combination structure of a Ta-Zr film and other magnetic films. Further, the three magnetic layers to be recorded may be coated Co--Cr, or may be made of a known material such as Ba ferrite.

Further, a fourth element may be added in addition to Co, Ta, and Zr.

6. Effects of the Invention As described above, the present invention uses Co-Ta as the magnetically permeable layer of the head.
- Since a Zr alloy is used, due to the Zr content, 4πM8 is large, ■■C is stable and small, and a magnetic film with high magnetization and low coercive force (and high permeability) is created. A head that can be manufactured with good reproducibility can be obtained.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, in which FIG. 1 is a schematic diagram of a magnetic head during recording, FIG. 2 is a schematic diagram of another head configuration, and FIG. 3 is a Co-Ta-Zr head configuration. Triangular composition diagram, Figure 4 is a graph showing changes in saturation magnetization characteristics due to Zr, Figure 5 is a graph showing reproduction output by magnetic heads of various head materials, Figure 6 is sputtering to create Co-Ta-Zr film. FIG. 7 is a schematic sectional view of the apparatus, FIG. 7 is a plan view of the target, and FIG. 8 is a schematic sectional view of another sputtering apparatus. In addition, in the symbols shown in the drawings, 14-------- Magnetic film (permeable layer) 15-- Magnetic recording medium 16-------- One auxiliary magnetic pole 17, --- , -1 main magnetic pole addition -11111 magnetic gap s -------1 substrate TXTIXT2 -------1 target. Agent: Hiroshi Aisaka, Patent Attorney (and others) Figure 1, Figure 2, Closed 4πMs Zr (a↑1%) Figure 5, Depth of movement (A lobby/V inch)

Claims (1)

[Claims] 1. A magnetic head characterized in that at least a portion of the magnetically permeable layer is formed of a cobalt-tantalum-zirconium alloy.