JPH08129712A - Magnetic head and its production - Google Patents

Abstract

PURPOSE: To improve wear resistance while maintaining film thickness not to degrade electromagnetic conversion characteristics. CONSTITUTION: This magnetic head has a chromium oxide thin film 4 and a metal chromium thin film layer 3 between the intersurface of the magnetic head and the chromium oxide thin film 4. The chromium oxide thin film 4 contains chromium and oxygen by 2:3 atomic ratio, shows a diffraction peak observed between 1.43Å and 1.67Å space of diffraction plane in X-ray diffraction spectroscopy, and has >=1500kgf/mm<2> Knoop hardness. The total film thickness of the chromium oxide thin film 4 and metal chromium thin film layer 3 is 10 to 100nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an audio pre-coder, a video pre-coder and a digital audio recorder.
The present invention relates to a magnetic head in a magnetic recording / reproducing apparatus such as a hard disk drive, a floppy disk, a magnetic card and the like, and a manufacturing method thereof.

[0002]

2. Description of the Related Art A magnetic head has a magnetic tape on its sliding surface.
It is difficult to avoid abrasion of the sliding surface because recording, reproduction and erasing are performed with the magnetic recording medium such as a magnetic disk and a magnetic disk sliding, and this abrasion causes deterioration of the magnetic head. ing.

Various devices have been proposed to solve this problem. For example, there is a method of applying a boron-imparting material to the sliding surface of the magnetic head and performing annealing to form a boron diffusion layer, thereby hardening the sliding surface to improve wear resistance. (Japanese Patent Publication No. 56-1682)
In addition, a method has also been proposed in which hardened metal atoms are injected and hardened into the sliding surface by ion implantation to improve wear resistance. (Japanese Patent Publication No. 55-12652) Further, it has been proposed to improve wear resistance by coating a thin film having high hardness on the sliding surface of the magnetic head.

[0004]

However, in these methods, the method by thermal diffusion of boron or ion implantation of boron requires strict control of temperature, cooling rate, etc., and therefore the production cost is high and at the same time. There is a problem that sufficient abrasion resistance is not obtained, and the inside of the magnetic head is adversely affected due to higher processing temperature and impact of ions.

In view of the above problems, the present invention provides a magnetic head having improved wear resistance without deteriorating electromagnetic conversion characteristics and a method of manufacturing the same.

[0006]

In order to solve the above-mentioned conventional problems, the magnetic head according to the present invention is characterized in that a protective film made of a chromium oxide thin film is formed on the head sliding surface.

[0007]

By forming a chromium oxide thin film on the sliding surface of the magnetic head through the metal chromium thin film layer so that the total thickness of the chromium oxide thin film and the chromium thin film layer is in the range of 10 to 100 nm, the gap between the head and the medium is reduced. It is possible to provide a magnetic head having a film thickness which is not affected by the spacing and which has extremely excellent wear resistance.

The chromium oxide layer exhibits excellent wear resistance especially under the following conditions. That is, the atomic ratio of chromium to oxygen is approximately 2: 3, the diffraction plane distance is between 1.43Å and 1.67Å in X-ray diffraction analysis, and the Knoop hardness of the chromium oxide thin film is 1500 kgf / mm ² More than that,
Is the condition.

[0009]

EXAMPLES Specific examples will be described in detail below. FIG. 1 shows a sectional view of the magnetic head of the present invention. In FIG. 1, 1 is a substrate, 2 is a cover, 3 is a metal chrome thin film,
4 is a chromium oxide thin film. A reactive high frequency sputtering method was used for producing the chromium oxide thin film. A chrome target having a diameter of 3 inches was used as the target. First, high frequency discharge is performed in argon gas to form a metal chromium thin film, and oxygen is introduced after a lapse of a predetermined time without interruption of discharge, and discharge is performed in a mixed gas of argon and oxygen to continuously discharge on the metal chromium thin film. A chromium oxide thin film was formed on. When the oxygen partial pressure in the sputtering gas is 5% or more, the amount of introduced oxygen is
It has been confirmed that the atomic ratio of chromium to oxygen in the chromium oxide thin film is not changed. Substrate is water cooled, sputtering power is 20
The sputtering pressure was 0 W and the sputtering pressure was constant at 5 mTorr. Also,
A zero or negative DC bias voltage was applied at the time of fabrication in order to improve the hardness and adhesion of the oxide film. The structure of the chromium oxide thin film was analyzed by X-ray diffraction analysis, and the atomic ratio of chromium and oxygen was analyzed by Auger electron spectroscopy.

The hardness of the chromium oxide thin film was evaluated with a Knoop hardness meter. The Knoop hardness meter used is Microhardness Tester MVK-1 manufactured by Akashi Seisakusho.

A commercially available cassette deck was used for the actual abrasion resistance test, and a chrome super II (90 minutes) manufactured by BASF was used as the tape. The tape was replaced with a new tape every 100 hours running, and the abrasion of the head surface was evaluated by an optical microscope.

These films were formed on a glass substrate for film hardness and X-ray diffraction analysis, and on the surface of a magnetic head for wear resistance evaluation. The head used for the abrasion resistance evaluation uses AlTiC for both the substrate and the cover.

FIG. 2 shows the relationship between the sputtering power and Knoop hardness studied in the present invention. When the sputtering power is 50 W, a film having a sufficient Knoop hardness cannot be obtained, but when the sputtering power is 100 W or more, the Knoop hardness of a substantially constant value is exhibited.

FIG. 3 shows the relationship between oxygen partial pressure and Knoop hardness. It can be seen that the Knoop hardness decreases as the amount of oxygen increases.

FIG. 4 shows the relationship between the Knoop hardness and the diffractive surface spacing in X-ray diffraction. It can be seen that the Knoop hardness increases as the diffractive surface spacing increases, resulting in a harder film. This relationship shows the same correlation when the sputtering power is 100 W or more, even when other film forming conditions are changed.

Table 1 shows some conditions of these examples.

[0017]

[Table 1]

In all of Examples 1 to 4, the diffractive surface spacing is in the range of 1.43Å to 1.67Å and the Knoop hardness is 1500 kgf / mm ² or more.

Next, some of the comparative examples are shown in (Table 2).

[0020]

[Table 2]

In Comparative Example 1, the film forming conditions were exactly the same as in Example 1, but the discharge was stopped once after forming the metallic chromium thin film as the interface layer with the head, and then 10% oxygen was introduced again. The discharge is started to form a chromium oxide thin film.

The results of evaluation of wear resistance of Examples and Comparative Examples are shown in (Table 3).

[0023]

[Table 3]

Example 1 and Comparative Example 1 are exactly the same except that the discharge is stopped or not stopped after the chromium thin film is formed on the head surface. From this, it can be seen that stopping the discharge during the transition from the chromium thin film to the chromium oxide thin film causes a large defect in the wear resistance.

From the comparison between Comparative Example 2, Example 1 and Example 4, it can be seen that the wear resistance is extremely lowered when the film thickness is thinner than 10 nm.

In Comparative Example 3, the Knoop hardness of chromium oxide was extremely small depending on the film forming conditions. in this case,
No diffractive surface is seen, and it seems to be an amorphous film.

In Comparative Example 4, although the diffractive surface was observed, the Knoop hardness of the chromium oxide thin film was not sufficient and the abrasion resistance was not obtained. Thus, although a diffractive surface appears, a film whose hardness is not sufficient has a weak X-ray diffraction intensity, and it may be that a crystalline element is contained in an amorphous film. Guess.

The diffractive surface intervals are all 1.43Å and 1.6.
It is between 7Å. We have not fully analyzed which crystal plane this diffraction plane hits, but the (300) plane (plane spacing 1.431)
We believe that either the (Å) plane or the (214) plane (plane spacing 1.465Å) is shifted by internal stress, or both diffraction peaks are overlapped.

With respect to the upper limit of the abrasion resistant film, sufficient abrasion resistance can be obtained even if the abrasion resistance is several μm. However, considering the spacing loss of the reproducing output of the head, it is desirable that it be 100 nm or less.

[0030]

As described above, according to the present invention, the chromium oxide thin film is formed on the head sliding surface, and the atomic ratio of chromium to oxygen in the chromium oxide thin film is about 2: 3. The surface spacing is between 1.43Å and 1.67Å, the Knoop hardness of the chromium oxide thin film is 1500 kgf / mm ² or more, and the metallic chromium thin film exists at the interface between the chromium oxide thin film and the head surface. A chromium oxide thin film satisfying the condition that the total thickness of the chromium thin film and the chromium thin film layer is in the range of 10 to 100 nm is coated on the sliding surface of the magnetic head to provide a space between the head and the medium. It is possible to provide a magnetic head having a film thickness that is not affected by singing and having extremely excellent wear resistance.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetic head of the present invention.

FIG. 2 is a diagram showing the relationship between sputtering power and Knoop hardness studied in the present invention.

FIG. 3 is a diagram showing the relationship between oxygen partial pressure and Knoop hardness studied in the present invention.

FIG. 4 is a diagram showing the relationship between the Knoop hardness and the diffraction plane spacing of X-ray diffraction studied in the present invention.

[Explanation of symbols]

 1 substrate 2 cover 3 metal chrome thin film 4 chrome oxide thin film

Claims (4)

[Claims] 1. A magnetic head comprising a chromium oxide thin film formed on a sliding surface with respect to a magnetic recording medium. 2. A metal chromium thin film layer is provided at the interface between the magnetic head surface and the chromium oxide thin film, and the total thickness of the chromium oxide thin film and the metal chromium thin film layer is in the range of 10 to 100 nm. The magnetic head according to claim 1, wherein the magnetic head is a magnetic head. 3. The chromium oxide thin film has a ratio of chromium to oxygen atoms of approximately 2: 3 in atomic ratio, and a diffraction peak is observed in X-ray diffraction analysis between diffraction plane intervals of 1.43Å and 1.67Å. The magnetic head according to claim 1 or 2, wherein the Knoop hardness is 1500 kgf / mm ² or more. 4. A method of manufacturing a magnetic head having a metal chromium thin film layer and a chromium oxide thin film on the surface of the magnetic head,
When forming the chromium oxide thin film and the metal chromium thin film layer, a negative bias voltage of zero volt or less is applied to the sliding surface with the magnetic recording medium, and oxygen is introduced without interrupting the process when forming the metal chromium thin film layer. A method for manufacturing a magnetic head, which comprises continuously forming a chromium oxide thin film on a metal chromium thin film.