JPH07210822A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain a magnetic head suitable for high density magnetic recording by forming a soft magnetic alloy thin film as a magnetic thin film to constitute a magnetic core. CONSTITUTION:At least each one layer of Ni-Fe alloy crystal magnetic thin film 1 and Co-Zr alloy amorphous magnetic thin film 2 are laminated. In figure (a), the crystal magnetic thin film 1 is formed only in the lower side of the amorphous magnetic thin film 2. In figure (b), thin films 1 are formed on the upper and lower sides of the thin film 2, In figure (c) thin films 2 and thin films 1 are alternately laminated. In any case, the lowermost layer of the laminated thin film body is a crystal magnetic thin film 1. The amorphous state of the Co-Zr alloy thin film is promoted with mismatching of the atomic arrangement with the Ni-Fe alloy thin film during formed or promoted with diffusion of atoms from the Ni-Fe alloy thin film into the Co-Zr alloy thin film. Since the Ni-Fe alloy thin film has excellent heat resistance and corrosion resistance, the heat resistance and corrosion resistance of the laminated thin film body as a whole are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a magnetic recording / reproducing apparatus such as an HDD (hard disk drive).

[0002]

2. Description of the Related Art Conventionally, as a magnetic core material of a thin film magnetic head in which a magnetic core and a current-carrying coil are thin film bodies, Ni
Often, Fe-based alloy thin films were used. 70-9
The 0 atom% Ni-Fe alloy thin film has a high magnetic permeability and excellent corrosion resistance, but since the saturation magnetic flux density is at most about 1.0T, it cannot be applied to recent high-density magnetic recording systems. There is.

On the other hand, as a magnetic thin film having a high saturation magnetic flux density and a high magnetic permeability, Co-Zr is disclosed in JP-A-59-125607.
Based amorphous alloy thin films are disclosed. Zr content is 5
A Co-Zr alloy of about atomic% or more exhibits excellent soft magnetic characteristics by being amorphized by being formed into a film by a sputtering method, and has a saturation magnetic flux density of about 1 when the Zr content is 5 atomic%. It is suitable for a magnetic core material of a magnetic head for high density magnetic recording at 0.5T.

[0004]

However, although a Co--Zr alloy thin film having a Zr content of about 5 to 6 atomic% can be amorphized, it is difficult to set and control film forming conditions. There is a problem in that the characteristics are deteriorated by the heat treatment in the manufacturing process of the magnetic head, because the characteristics are thermally unstable even after the film formation.

In practical use as a thin film magnetic head, the magnetic core undergoes a heat cycle of heating and cooling due to heat generation of the coil due to the recording current, and the thermally unstable amorphous alloy thin film gradually exhibits magnetic characteristics. There is also the problem of deterioration.

Although such a problem is improved to some extent by increasing the Zr content or adding the third element, increasing the Zr content or adding the third element causes a decrease in the content of Co as a magnetic atom. This means that the saturation magnetic flux density is lowered.

The present invention provides a magnetic head suitable for high density magnetic recording by clarifying the structure of a soft magnetic alloy thin film having a high saturation magnetic flux density and excellent heat resistance and corrosion resistance.

[0008]

In the magnetic head according to the present invention, at least a part of the magnetic core is a crystalline magnetic thin film made of a Ni--Fe alloy or the like and an amorphous magnetic thin film made of a Co--Zr alloy or the like. A magnetic thin film is formed by laminating at least one layer each, and the lowermost layer of the laminated thin film is formed by the crystalline magnetic thin film.

[0009]

According to the above-described structure of the present invention, the atomic arrangement inconsistency with the Ni-Fe alloy thin film during the formation of the Co-Zr alloy thin film and the atoms in the Ni-Fe alloy thin film are changed to C.
By diffusing into the o-Zr alloy thin film, Co-
Amorphization of the Zr-based alloy thin film is promoted.

Since the Ni-Fe alloy thin film is excellent in heat resistance and corrosion resistance, the Ni-Fe alloy thin film and Co
When laminated with the -Zr alloy thin film, the heat resistance and corrosion resistance of the laminated thin film are improved without lowering the saturation magnetic flux density of the Co-Zr alloy thin film.

Further, the Ni--Fe alloy thin film is a SiO ₂ film forming base of a magnetic core layer in a thin film magnetic head.
The strong adhesion to the oxide insulator layer such as
By interposing the -Fe-based alloy thin film between the Co-Zr-based alloy thin film and the oxide insulator layer, the magnetic core layer made of a laminated thin film body having a high saturation magnetic flux density is firmly formed on the oxide insulator layer. As a result, the reliability of the thin film magnetic head is improved.

[0012]

EXAMPLES Examples of the present invention will be described below.

In the magnetic head of the present invention, as shown in FIGS. 1A to 1C, at least a part of the magnetic core has a crystalline magnetic thin film 1 made of Ni--Fe alloy or the like and Co. A thin film body is formed by laminating at least one layer of an amorphous magnetic thin film 2 made of a —Zr-based alloy or the like. 1A shows an example in which the crystalline magnetic thin film 1 is arranged only under the amorphous magnetic thin film 2, and FIG. 1B shows a crystalline magnetic thin film under and above the amorphous magnetic thin film 2. 1 shows an example in which 1 is arranged, (c) shows an example in which the amorphous magnetic thin film 2 and the crystalline magnetic thin film 1 are alternately laminated. In either case, the bottom layer of the laminated thin film body is crystalline magnetic. It is composed of the thin film 1. Note that FIG.
Reference numeral 3 in FIG. 3 denotes a film forming base of the laminated thin film body.

As a magnetic head to which the present invention is applied, not only a thin film magnetic head in which a magnetic core and a current-carrying coil are formed of a thin film but also a thin film forming a magnetic core is sandwiched between non-magnetic substrates. MI with a magnetic thin film at the gap abutting part of the magnetic head or ferrite magnetic core
A G (metal in gap) type magnetic head or the like can be used.

Here, the film thickness of the crystalline magnetic thin film in the laminated thin film which characterizes the present invention will be described.

FIG. 2 shows Ni-of various thicknesses on a glass substrate.
An Fe alloy thin film is formed and Co-Z with a thickness of 1 μm is formed on the thin film.
Coercive force Hc in a laminated thin film body formed with an r alloy thin film
(Curve A) and saturation magnetic flux density Bs (curve B) are shown.

A multi-cathode type magnetron sputtering apparatus was used for film formation, and a Ni—Fe alloy with about 80 atomic% Ni and a Co—Zr alloy with about 5.5 atomic% Zr were used. Further, in order to impart anisotropy to the magnetic thin film and improve the magnetic permeability, a permanent magnet was installed around the substrate and a film was formed while applying a static magnetic field of 30 Oe in a predetermined direction parallel to the substrate surface.

According to FIG. 2, Ni-- is formed under the Co--Zr film.
The decrease in coercive force due to the interposition of the Fe film, that is, the improvement of the soft magnetic characteristics is noticeable even when the thickness of the Ni—Fe film is 50 Å, but the thin film lamination accompanying the increase in the film thickness of the Ni—Fe film The tendency of the coercive force of the body to decrease is Ni-F.
e When the thickness of the film exceeds 100 Å, it gradually becomes gentle, and when it exceeds 500 Å, the coercive force does not decrease any more.

On the other hand, the decreasing tendency of the saturation magnetic flux density as a thin film laminated body is linear with the increase of the film thickness of the Ni--Fe film.
It can be considered that about 1.55 T of the o-Zr single layer film is simply diluted with about 1.0 T of the Ni-Fe single layer film, and C
There is no large downward shift from the simple dilution rule as in the tendency of the saturation magnetic flux density to decrease with the increase of the Zr content in the o-Zr film (see FIGS. 3 and 4 described later).

Next, the amorphized composition region of the magnetic alloy thin film to be made amorphous will be described.

In FIG. 3, a Ni--Fe alloy thin film (thickness 300 Å) is formed on a glass substrate, and Co having various compositions is formed thereon.
-Coercive force Hc (curve C) and saturation magnetic flux density Bs in a laminated thin film body formed with a Zr alloy thin film (thickness 1 μm)
FIG. 4 shows (curve D), and FIG. 4 shows Co—Zr alloy thin films (thickness 1 μm) having various compositions formed directly on a glass substrate.
m) shows the coercive force Hc (curve E) and the saturation magnetic flux density Bs (curve F) in m).

As can be seen by comparing FIGS. 3 and 4,
In the Co-Zr single layer film, the composition region in which the coercive force is 1 Oe or less is about 5 atom% Zr or more, whereas Co-Zr
In the laminated film of the film and the Ni—Fe film, the composition region in which the coercive force is 1 Oe or less extends to about 4.5 atomic% Zr or more,
The saturation magnetic flux density is about 0.0 when the coercive force is about 1 Oe.
3T higher.

The value of the coercive force of 1 Oe is a standard value of the soft magnetic characteristics required for the magnetic core material of the magnetic head. In FIGS. 3 and 4, the coercive force is 1 Oe.
The coercive force is remarkably reduced on the high Zr concentration side near the composition of the Co-Zr film, which is the reason why the Co-Zr film becomes amorphous on the Zr high concentration side near the composition. It is considered to be a phenomenon corresponding to

Regarding the increase in coercive force due to temperature rise, if the temperature at which the coercive force is 1 Oe or more is regarded as the crystallization temperature, the Co--Zr film formed on the Ni--Fe film is
The crystallization temperature was increased by about 15 ° C as compared with the Co-Zr single layer film.

Further, in the Co—Zr single layer film of 5 to 6 atomic% Zr, when the substrate temperature at the time of film formation exceeds 100 ° C., crystallization and coercive force remarkably increase.
In the Co-Zr film formed on the -Fe film, the substrate temperature is set to 2
Even at 00 ° C, the coercive force did not become large.

Next, the corrosion resistance of the laminated thin film which characterizes the present invention will be described.

FIG. 5 shows a Co-Zr single-layer film (white triangle) with a thickness of 1 μm, and a two-layer film (Co-Zr film with a thickness of 1 μm formed on a Ni-Fe film with a thickness of 300 Å). Black square mark), 1 μm thick on a 300-Å-thick Ni-Fe film
Co-Zr film is formed and the thickness of 300Å
For the three-layer film (white squares) with the Ni-Fe film of No. 3, a salt spray test according to the JIS standard (standard number JIS-Z2317) was performed, and the change in the saturation magnetic flux density with the passage of time was initially measured. The values are standardized by the value of the saturation magnetic flux density.

According to FIG. 5, the Ni-Fe film and the Co-Zr film are formed.
It was found that the laminated film with the film is superior in corrosion resistance as compared with the Co-Zr single layer film.
In the laminated film formed with the Fe film, almost no decrease in saturation magnetic flux density is observed.

[0029]

As described above, in the magnetic head of the present invention, the magnetic thin film forming the magnetic core is made of a soft magnetic alloy thin film having a high saturation magnetic flux density and excellent soft magnetic characteristics, heat resistance and corrosion resistance. As a result, the magnetic head becomes suitable for high density magnetic recording.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a laminated thin film body according to an embodiment of the present invention.

FIG. 2 is an experimental result diagram showing an example of the present invention and a comparative example.

FIG. 3 is an experimental result diagram showing an example of the present invention and a comparative example.

FIG. 4 is an experimental result diagram showing a comparative example.

FIG. 5 is an experimental result diagram showing an example of the present invention and a comparative example.

[Explanation of symbols] 1 crystalline magnetic thin film 2 amorphous magnetic thin film 3 film-forming substrate

Claims (3)

[Claims] 1. At least a part of the magnetic core is composed of a thin film body in which at least one layer of a crystalline magnetic thin film and at least one layer of an amorphous magnetic thin film are laminated, and the bottom layer of the laminated thin film body is
A magnetic head comprising the crystalline magnetic thin film. 2. The magnetic head according to claim 1, wherein the crystalline magnetic thin film is made of a Ni—Fe based alloy, and the amorphous magnetic thin film is made of a Co—Zr based alloy. 3. The magnetic head according to claim 1, wherein the thickness of the crystalline magnetic thin film is 50 Å or more per layer.