JPH07111925B2 - Laminated magnetic film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic head core material, and more particularly to a magnetic head core laminated magnetic film that exhibits suitable performance for high density magnetic recording.

[Conventional technology]

The progress in high density magnetic recording is remarkable, and the coercive force of the conventional oxide tape is 600-700 Oe due to the advent of metal tape.
For 1500 to 2000 Oe has been obtained.
In order to sufficiently record on such a high coercive force magnetic recording medium, a magnetic material for a magnetic head core having a high saturation magnetic flux density is required. As this magnetic material, there is an alloy containing Fe, Co, and Ni as the main components, and the saturation magnetic flux density is 10,000 G or more.
The Si-based alloy has a saturation magnetic flux density of 18000 G and is under development as a high-density magnetic head material (Japanese Patent Laid-Open No. 59-18).
2938).

A conventional magnetic recording method is shown in FIG. The magnetic recording medium 1 comprises a non-magnetic substrate 2 on which a perpendicularly magnetized film 4 of Co--Cr or the like having an easy axis of magnetization in the direction perpendicular to the film surface is formed via a base film 3 of permalloy or the like. The magnetic head is composed of a main magnetic pole 5 and an auxiliary magnetic pole 9, and the main magnetic pole 5 is magnetized by a signal current flowing in the exciting coil 10. The perpendicular magnetic field generated in the magnetic pole extending to the tip of the magnetic head causes the perpendicular magnetic film of the magnetic recording medium 1 to be magnetized. Record the signal at 4. Therefore, in order to obtain a vertical component magnetic field having a steep distribution, the thickness of the tip of the main pole 5 is 0.
It must be 5 μm or less. Since the magnetic flux density is high in this portion, a magnetic thin film having high saturation magnetic flux density and high magnetic permeability is required. However, since the main magnetic pole film is thin and magnetic saturation occurs, a high saturation magnetic flux density of 15000 G or more is required for a film thickness of 0.5 μm or less.

As a magnetic material film aiming at such a high saturation magnetic flux density and a high magnetic permeability, a multilayer magnetic material film in which magnetic material films are laminated via an intermediate layer has been recently studied (Japanese Patent Laid-Open No. 59-990).
Five). In this multilayer magnetic film, it is generally said that it is preferable to use a magnetic material having a high magnetic permeability as the intermediate layer inserted between the main magnetic bodies. Therefore, although Permalloy or the like has been often used as the intermediate layer, its magnetization mechanism or the like has not been clarified.

[Problems to be solved by the invention]

When forming the above-mentioned multilayer magnetic film, an RF sputtering device is used, and at least two types of rotary target holder main magnetic target and intermediate layer target are placed in the rotary target holder. One of these is selected by the rotation of the holder to form a film. By this method, the main magnetic material and the intermediate layer are sequentially laminated to form a multilayer magnetic material film. As described above, the above-mentioned conventional technique requires a target exchanging mechanism, which causes a problem in simplifying the apparatus. Further, the saturation magnetic flux density of the obtained multilayer magnetic film also tends to decrease as the volume of the intermediate layer increases, which is not preferable.

Therefore, an object of the present invention is to provide a laminated magnetic film having a high saturation magnetic flux density and which can be easily formed by a simple method. Another object of the present invention is to provide a magnetic film suitable for a magnetic head for perpendicular magnetic recording, which has a low coercive force and a high magnetic permeability and exhibits excellent recording / reproducing characteristics for a high coercive force recording medium.

[Means for solving problems]

The above object is achieved by stacking a metal magnetic material having a high saturation magnetic flux density and a small magnetostriction as a main magnetic material film, and laminating an amorphous film composed of the same kind of component as the main magnetic material film as an intermediate layer. It The thickness of the intermediate layer is preferably 1 to 10 nm,
It is preferable that the main magnetic film and the intermediate layer contain iron or iron as a main component.

[Action]

As a result of detailed examination of the laminated magnetic film, the present inventors have revealed that the role of the intermediate layer is to divide the columnar crystal structure so that the magnetization can be easily oriented in the film plane. At this time, it has been found that the crystal grain size of the main magnetic film can be kept small when the intermediate layer is amorphous, and as a result the coercive force is reduced. Furthermore, it has been clarified that a magnetic material having a high magnetic permeability is more preferable than a non-magnetic material for the intermediate layer.

The inventors of the present invention continued to study a laminated magnetic film using an amorphous high-permeability material for the intermediate layer based on the above-mentioned examination results. As a result, iron or an iron-based main magnetic film was used. ,
It was confirmed that a desired magnetic layer having a low coercive force can be obtained by using a material having the same or the same kind of component as the main magnetic film as the intermediate layer and making it amorphous. Further, as a result, the saturation magnetic flux density observed in the conventional laminated magnetic film decreases, that is, the saturation magnetic flux density of the main magnetic film decreases by the volume of the intermediate layer, which is 80 to 90% of the original value. It became clear that the phenomenon of becoming. Further, from the viewpoint of the apparatus for forming the laminated magnetic film of the present invention, since the main magnetic film and the intermediate layer are made of the same kind of material, the same target can be used, and the conventional laminated magnetic film can be used. There is no need to provide a target exchange mechanism (rotary target holder, etc.) like in the case of forming
It became easy.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 The magnetic film was formed by the ion beam sputtering method. Pure iron was used for the main magnetic film and the intermediate layer of the laminated magnetic film. The pure iron film was made amorphous by irradiating the substrate stage 14 with the ion beam emitted from the substrate irradiation ion gun 12, as shown in FIG. The preferable ion beam sputtering conditions were as follows.

Target… Fe (99.9% purity) Ion gun acceleration voltage for vapor deposition… 1200V Ion gun ion current density for vapor deposition… 1.4mA / cm ² Ion gun acceleration voltage for substrate irradiation… 800V Ion gun current density for substrate… 0.15mA / cm ² Ar gas pressure … 1.4 × 10 ^-4 Torr Substrate temperature… 40 ℃ Under this sputtering condition, when forming the main magnetic film, the ion current density of the substrate irradiation ion gun 12 is 0.02mA.
/ cm ² aperture below, line film formation by an ion current density of the substrate irradiated for ion gun 12 0.15 mA / cm ² the return time of forming the intermediate layer Natsuta. The main magnetic film had a film thickness of 50 to 200 nm and the intermediate layer had a film thickness of 1 to 10 nm, and 3 to 10 layers were sequentially laminated to form a laminated magnetic film.

The saturated magnetic flux density of the obtained pure iron laminated magnetic film was 20 to 22 KG, which was similar to the saturated magnetic flux density of pure iron single layer film of 21 to 22 KG. The coercive force is greatly reduced compared to 2-5 Oe of a single layer film
It showed a value of 0.3 to 1 Oe, and became a film suitable as a magnetic head core material.

The intermediate layer was analyzed by the RHEED (reflection high energy electron diffraction) method and the transmission electron beam diffraction method, and as a result, it was confirmed to be amorphous.

Example 2 In Example 1, the target was changed from pure iron to the material shown in Table 1, and a multilayer magnetic film was formed by the ion beam sputtering method as in Example 1. As a result, the first
As shown in the table, the magnetic characteristics of the laminated magnetic film made of a material whose main component is iron changes depending on the thickness of the intermediate layer. The saturation magnetic flux density decreased remarkably when the thickness of the intermediate layer became thicker than 10 nm, and the value became less than 20 KG.

The above results show that the thickness of the intermediate layer is preferably 1 to 10 nm from the viewpoint of high magnetic characteristics. Further, as described above, it was revealed that an amorphous magnetic film can be extremely easily obtained by the method of irradiating with an ion beam, and a laminated magnetic film can be formed.

The magnetic pole recording head using the above-mentioned laminated magnetic film as the main pole of the magnetic head for perpendicular or in-plane recording has a recording density of 100 KBPI or more, which exceeds the recording density of 70 KBPI (kilobits / inch) of the conventional magnetic recording head. .

[Effects of the Invention] As described above, the laminated magnetic film according to the present invention can be applied as an excellent magnetic head core material exhibiting a high saturation magnetic flux density (20 KG or more) and a low coercive force (1 Oe or less). Therefore, when the present invention is used as a main magnetic pole film of a magnetic head for perpendicular or in-plane magnetic recording, a magnetic flux is generated at the tip of the magnetic pole without causing magnetic saturation even with a thin film of about 0.2 μm. Therefore, it is possible to achieve ultra high density magnetic recording. Further, in the laminated magnetic film of the present invention, the main magnetic film and the intermediate layer are composed of the same kind of components, so that the number of required targets is reduced and a complicated device such as a target exchange mechanism is not required.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the structure of a magnetic head for perpendicular magnetic recording and a magnetic recording medium, and FIG. 2 is a sectional view of an ion beam sputtering device used in this embodiment. 1 ... Magnetic recording medium, 2 ... Non-magnetic substrate, 3 ... Underlayer film, 4 ... Perpendicular magnetization film, 5 ... Main pole, 6 ... Substrate, 7
...... Gear regulating material, 8 …… Filling material, 9 …… Auxiliary magnetic pole,
10 …… Protective material, 11 …… Vapor deposition ion gun, 12 …… Substrate irradiation ion gun, 13 …… Target, 14 …… Substrate stage, 15 …… Exhaust port.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryoichi Nakatani 1-280, Higashi Koigakubo, Kokubunji City, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (56) References JP-A-59-130408 (JP, A) JP-A-59 -18625 (JP, A) JP-A-59-17222 (JP, A)

Claims (2)

[Claims] 1. A main magnetic film of iron or iron, which has a high saturation magnetic flux density and has a predetermined thickness and a predetermined number of metal magnetic substances, is substantially the same as or the same as the main magnetic film. A laminated magnetic film, wherein an amorphous film composed of the component (1) is laminated as an intermediate layer. 2. A laminated magnetic film, wherein the film thickness of the intermediate layer according to claim 1 is 1 to 10 nm.