JPH0283803A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To obtain the magnetic disk device of high reliability provided with a ferrite head by using a zirconium oxide film of 100 to 1,000Angstrom thickness contg. 2 to 6mol% ytrrium oxide as the protective film of a magnetic recording medium layer to the ferrite head. CONSTITUTION:An underlying layer 2 and the magnetic recording medium 3 are successively formed on a substrate 1 and the zirconium oxide film contg. 4mol% ytrrium oxide is formed to 500Angstrom thickness as the protective film 4 thereon. The zirconium oxide having the proper hardness and toughness is provided on the surface of the magnetic recording medium in such a manner, by which the magnetic disk device having the small friction force and attraction force between the magnetic disk and magnetic head slider and having the sufficiently high durability and reliability is obtd. for the head made by using the ferrite.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to the structure of a magnetic disk for a ferrite head.

[Conventional technology]

In recent years, the importance of external storage devices such as magnetic disk drives in computer systems has increased, and the demand for high recording speed has been increasing.

A magnetic disk device consists of a recording/reproducing head and a magnetic disk as main components.The magnetic disk rotates at high speed, and the recording/reproducing head, that is, the magnetic head, floats a minute distance above the magnetic disk. In order to increase the recording density and performance of magnetic disks, it is necessary to make the magnetic recording medium thinner, more uniform, improve magnetic properties (improve coercive force and squareness ratio),
Examples include lowering the flying height of magnetic heads.

Up until now, magnetic disks have been manufactured by coating a mixture of a polymeric material such as a binder and γ-Fe203 magnetic recording medium particles. This method has limitations in making the magnetic recording medium thinner and more uniform. For this reason, recently, magnetic recording media have been provided as continuous thin films on substrates by methods such as sputtering. γ-F
FIG. 9 shows an example of the configuration of a magnetic disk using e20g as a continuous thin film medium. FIG. 9 is a diagram showing a cross section of a thin film magnetic disk reported, for example, in Vol. 31, No. 9, pages 1731 to 1744 of the Research and Practical Application Report of the Telecommunications Public Corporation. In the figure, (1) is a disk-shaped aluminum alloy base material, (2)
(3) is a γ-Fe203 thin film that becomes the magnetic recording medium.

Currently, magnetic disk drives use the contact e-start-stop (aSS) method, in which the magnetic disk and magnetic head come into contact with each other during startup and stop. Rotate. The frictional force generated between the magnetic head and the magnetic disk in this contact friction state wears out the surface of the magnetic head and the magnetic disk, and also causes scratches on the magnetic head and magnetic recording medium film. When a continuous thin film is used, even a slight scratch will result in the recording medium being missing, leading to the loss of the recorded signal.

This is a serious problem regarding the reliability of the magnetic disk device as an external storage device.

Therefore, in order to protect the magnetic recording medium from contact friction and contact damage between the magnetic head and the magnetic recording medium, a 51oz film, a carbon film, and an A120B film are coated on the surface of the magnetic disk.
It has been proposed to provide a protective film such as a film (for example, Akio Tago et al., 8th Japanese Society of Applied Magnetics, Abstracts of Academic Lectures (19B4), p. 222: Yoshihiro Kimachi et al., 1988 Institute of Electronics and Communication Engineers) Proceedings of the General National Conference (1986), l-1
Page 66: Published in Hiroyasu Karimoto et al., Proceedings of the 30th Research Presentation of the Japan Lubrication Society (1985), page 141. ). However, if the magnetic recording medium is metal, this
The film also serves as a protective film that prevents corrosion of the metal film.

On the other hand, progress is also being made in making magnetic heads more resistive.

Studies are being conducted to improve the precision of the disk surface and to improve the head crash resistance in order to ensure a stable head flying state at low flying heights and prevent collisions between the magnetic head and the magnetic disk (head crash). In particular, the improvement in disk surface precision is remarkable, and the Rmax ij of conventional disks is
(more than 2,000 people), but now Rmax is 10
The number has fallen by more than an order of magnitude to around 0 people. As the surface precision of disks improves year by year, problems have arisen in which the magnetic head sticks to the surface of the magnetic disk, and even when the magnetic disk begins to rotate, the magnetic head cannot fly, resulting in damage to the magnetic head (for example, Journal of Applied Physics (J, Appl Ph, ys,
) Volume 55, No. 6, Page 2254 (E, M, Roaa
1 and others)). For this reason, methods have been considered such as applying fine powder to the surface of the substrate, which has been finished like a mirror surface, or re-polishing or etching it to form minute protrusions on the surface (for example, Japanese Patent Laid-Open No. 59-117735 .60-
38720.60-40528, 61-29418.6
1-203259.6l-261820)0 After this, a magnetic recording medium and a protective film are provided.

[Problem to be solved by the invention]

A conventional magnetic disk is constructed as described above, and forming an oxide film from a solution is known as a simple method for forming an oxide film as a retainer. When forming a 5102 film, an Al2O3 film, etc. from a solution using the sol-gel method, heat treatment is performed, but heat treatment at a temperature below about 400°C that does not change the characteristics of the magnetic recording medium does not result in sufficient vitrification. Hardness and strength are 6D lower than regular ceramics (
Masahiro Yanagisawa, Proceedings of the 30th Anniversary National Conference of the Japan Lubrication Society (1985), p. 45). For example, when synthesizing glass from metal alkoxide, the heat treatment temperature necessary to vitrify the gel obtained by hydrolyzing the metal alkoxide is 600 to 1000"C, and it has the same properties as silica glass produced by the melting method. This is said to be the case when heat treatment is performed at 900 to 1000"C (Saio Sakuhana, "Science of Glass Amorphous Materials", Rokaku Uchida 1!l11 (1983),
(pp. 147-164) 0 For this reason, the oxide film prepared from a solution was not sufficient in both hardness and strength.

In this respect, oxide films and carbon films formed by sputtering etc. can have excellent strength (
For example, Yoshihiro Honmachi et al., Proceedings of the 1986 National Conference of the Institute of Electronics and Communication Engineers (1986), p. I-166). However, with current substrates that have minute protrusions on their surfaces, protective films such as 8102 film, AJO3 film, and carbon film, which are seen in many conference presentations, have the disadvantage that they are hard but brittle. Ta. That is, since the magnetic head comes into contact with the top of a minute protrusion, the image layer film portion corresponding to the protrusion is fragile and is therefore broken and scraped off. Regarding this property, thin film oxides are very similar to bulk ceramics. Furthermore, even if the magnetic recording medium is not damaged,
A problem arose in that the minute protrusions on the surface disappeared and the magnetic head was attracted to it, making it impossible for the magnetic head to fly. Also, even if the hardness is too large, the Vickers hardness is 65
For ferrite heads of about 0.0, there are problems such as the floating surface of the magnetic head (contact with the magnetic disk) being worn out and damaging the magnetic head, and the magnetic disk being damaged by abrasion particles of the head. there were.

This invention was made to solve the above problems, and prevents damage to the magnetic disk by the magnetic head, prevents peeling of the protective film, and prevents the magnetic head from adhering to the magnetic disk substrate. The purpose of this invention is to prevent head wear caused by magnetic disks and to obtain a highly reliable magnetic disk device.

[Means to solve the problem]

The magnetic disk device according to Issue 11 uses 10CI-1 containing 2 to 6 mol % of yttrium oxide as a sg of a magnetic recording medium layer for a ferrite head.
A zirconium oxide film with a thickness of 1,000 mm is used.

[Effect]

The magnetic disk device according to the present invention provides a zirconium oxide film with appropriate hardness and toughness on the surface.
For heads using ferrite, the durability of the film on the surface of the magnetic disk is much stronger than that of conventional oxide films or carbon films, increasing reliability.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a sectional view showing a magnetic disk according to an embodiment of the present invention, in which (1) is an Al-Mg alloy substrate, (2)
is the underlayer of the magnetic recording medium layer, (3) is the magnetic recording medium layer,
(4) is a protective film made of zirconium oxide film.

A base layer (2) made of N1-P6 or Ni-0u-P plating film is formed on the surface of the Al-Mg alloy substrate (1), and tape polishing is applied to the mirror-finished substrate. Using a wrapping tape WA#6000. Pressure Ikg,
Board rotation speed 200rp! Els tape feed speed 20mm
Texture processing was performed under the condition of /min. This yields a board with an Rmax of about 500 people. A magnetic recording medium was deposited on this substrate by sputtering.

Example 1 r-Fe2O2 was used as a magnetic recording medium.

On this magnetic recording medium layer (3), 4 m of yttrium oxide was added.
A film of zirconium oxide containing ox% was formed by sputtering. The sputtering conditions were RF power of 300 W/8 inches, Ar pressure of 3 mTorr, and no substrate heating. The thickness of the zirconium oxide film was 500 mm.

Example 2 Co-Ni-0r was used as the magnetic recording medium.

On this magnetic recording medium layer, 4 mox% of yttrium oxide was added.
A film containing zirconium oxide was formed by electron beam evaporation. The deposition conditions were accelerated type EE10 with a 'v1 current of 100 mA.
The substrate temperature was 150°C and the oxygen pressure was 1 mTorr.

The thickness of the zirconium oxide film was 600.

Comparative example 1 γ-F0203 was used as a magnetic recording medium.

A 51o2 film was formed by sputtering on this magnetic recording medium layer. The sputtering conditions are almost the same as in Example 1.

The film thickness of 5102 was set to 500 people.

Comparative example 2 20 g of r-Fe was used as a magnetic recording medium.

On top of this magnetic recording medium layer is 9 mos of IJ oxide.
A film of 1% zirconium oxide was formed by sputtering. Sputtering conditions: ■Power 300W/8 inches;
The substrate was not pressurized at an Ar pressure of 3 mTorr. The thickness of the zirconium oxide film was 500 mm.

The initial characteristics of magnetic disks including these comparative examples are shown below.

A characteristic diagram of the surface roughness of the magnetic disk according to Example 1 measured using a stylus type surface roughness meter is shown in FIG.

Since Example 2 and Comparative Example 1.2 showed similar characteristics,
Characteristic diagrams are omitted. Minute irregularities were observed on the surface of the disk.

A 3370 type ferrite head was brought into contact with the surfaces of the magnetic disks according to Examples 1 and 2 and the magnetic disk according to Comparative Example 1.2 to measure the coefficient of static friction. O, ], 9 for the magnetic disk according to Example 1, 0.20 for the magnetic disk according to Example 2, and 0.20 for the magnetic disk according to Comparative Example 1.
．． In the magnetic disk according to Comparative Example 2, it was 0.19.

All exhibited good characteristics. Here, an O8S test, which is a magnetic disk durability test, was conducted. The head used was a 3370 type head whose slider material was ferrite. Figure 3 shows the results of the aSS test, where the vertical axis is the normalized playback output with the initial playback output as 1, and the horizontal axis is 0.
88 times (X104) were taken. In the figure, the line connecting the O marks indicates the case of the disk according to Example 1.2 of the present invention, the line connecting the X marks indicates the case of the comparative example 11, and the line connecting the Δ marks indicates the case of the disk according to the comparative example 2.

In the case of the disc according to embodiment 1.2 of the invention, 0
No decrease in reproduction output was observed even after 8,820,000 times. On the other hand, in Comparative Example 1, although no decrease in reproduction output was observed initially, the reproduction output gradually began to decrease around 58,000 CBs, and in Comparative Example 1, cs 82
At 0000 times, the initial value was 5(l).Also, comparative example 2
In this case, the decrease in playback output is small compared to Comparative Example 1, but (
A head crash occurred around 12,000 times on the 38S. It is thought that this is because the zirconium oxide film is hard, so the ferrite magnetic RAD slider is severely damaged, the floating surface of the slider is scraped, and the abrasion powder causes the head crash.

The surface roughness of the magnetic disk subjected to 85,000 OS cycles was measured using a stylus type surface roughness meter. FIG. 4 is a characteristic diagram showing the surface roughness of the magnetic disk according to Example IK, FIG. 5 is a characteristic diagram showing the surface roughness of the magnetic disk according to Example 2, and FIG. 6 is a characteristic diagram showing the surface roughness of the magnetic disk according to Comparative Example 1. FIG. 7 is a characteristic diagram showing the surface roughness of the magnetic disk according to Comparative Example 2. (5) in the figure represents the area where the magnetic head contacts the magnetic disk due to contact start/stop. A comparison with the roughness of the periphery shows that the magnetic disks according to Examples 1 and 2 and Comparative Example 2 maintain their initial surface roughness. In contrast, it can be seen that in the magnetic disk according to Comparative Example 1, the portions corresponding to the minute protrusions are removed. However, large linear scratches along the sliding direction were observed on the floating surface of the magnetic herad slider made of ferrite that was subjected to the aSS test in Comparative Example 2, and the durability of the head/disk was affected by the amount of yttrium oxide added. It is clear that there is a difference.

Further, the head was brought into contact with the surface of the magnetic disk which had been subjected to the 0,885,000 cycles, and was left at 60'C and 85% for 8 hours, and the coefficient of static friction was measured. 0,22 for the magnetic disk according to Example 1, and 0 for the magnetic disk according to Example 2.
624 and the magnetic disks of Comparative Examples 1 and 2, the phenomenon of adsorption was observed when the ratio exceeded 0.9.

Figures 8(a) and 8) are characteristic diagrams showing the relationship between the bending strength and toughness of zirconium oxide and the content of yttrium oxide, respectively. In order to achieve high toughness and hardness suitable for ferrite, it is recommended to use IJ oxide as a protective film in the range of 2 to 6 m01, especially 2 to 3
It can be seen that the range of m01% is good.

That is, in the case of a material with relatively low Vickers hardness such as a ferrite head, if the yttrium oxide content is too high, the hardness will be too high, so the yttrium oxide content should be 6 m
The content is preferably 01% or less, and from the viewpoint of toughness, 2m01% or more is preferred.

If the film thickness of zirconium oxide is less than 100 Å, it will not be a uniform film, and if it is more than 100 Å, the distance between the magnetic head and the magnetic recording medium layer of the magnetic disk will increase.
This has the negative effect of reducing the playback output. For this reason, the zirconium oxide film is suitable for 100 to 1000 people. 300~ in terms of ease of film formation, uniformity, and playback output.
800 A is desirable.

In addition, aluminum oxide, cerium oxide, silicon carbide, titanium carbide, etc. can be considered as additive components of zirconium oxide, but addition of yttrium oxide is essential to realize a zirconium oxide film with high toughness.

In addition, if the surface roughness of the base material is R + nax less than 100 A, adhesion will definitely occur, and if it is more than 1 OOO Å, the protrusions will collide with the flying magnetic head, which will adversely affect the flying characteristics of the magnetic head, so the undesirable 0 static friction force will be reproduced. In order to keep it small and stable with good performance, Rmax is preferably 400 to 800 people.

In the above embodiment, the magnetic recording medium layer (3) is made of r-Fe203
Although the case has been described, other metal oxide media such as Or○2 may also be used and the same effects as in the above embodiments can be obtained.

Further, in the above embodiment, the magnetic recording medium layer (3) is Go-N.
Although the case of i-Or is explained, other Co-Ni,
An alloy medium such as 0o-Or or Fe or a metal medium may be used, and the same effects as in the above embodiments can be obtained.

In addition, in the above embodiment, the base layer (2) is a N1-P plating film or a Ni-0u-P plating film, but other alumite films or the like may also be used to achieve the same effect as in the above embodiment. play.

Further, in the above embodiment, the base layer (2) is made uneven to obtain a predetermined surface roughness, but the protective film (4) may be subjected to an uneven treatment.

Further, in the above embodiment, the ferrite head has a Vickers hardness of about 650, but ferrite heads having other Vickers hardnesses can also have similar effects.

〔Effect of the invention〕

As described above, according to the present invention, a zirconium oxide film having a thickness of 100 to 1000 mm and containing 2 to 6 m01% of yttrium oxide is used as a protective film for the magnetic recording medium layer in a ferrite head. It is possible to form a protective film with appropriate hardness and toughness that corresponds to the magnetic head sliver, and the frictional force and adsorption force between the magnetic disk and the magnetic head sliver are small, resulting in a sufficiently durable and reliable magnetic disk device. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a magnetic disk according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing initial surface roughness measured by a surface roughness meter, and FIG. 3 is a magnetic disk according to an embodiment of the present invention. Figures 4 and 5, and Figures 6 and 7 are characteristics diagrams showing the relationship between the number of aSS and playback output, showing the results of acceleration tests on disks and conventional magnetic disks, respectively.
Characteristic diagrams showing the surface roughness measured by the surface roughness meter of the magnetic disk according to the embodiment of the present invention and the conventional magnetic disk after 5,000 cycles, and FIGS. 8(a) and 8(b) respectively show the bending strength of zirconium oxide. FIG. 9 is a cross-sectional view showing a conventional thin film magnetic disk. (1)... Al-Mg alloy substrate, (2)... Underlayer, (3)... Magnetic recording medium layer, (4)... Protective film. Or it shows the priest part.

Claims (1)

[Claims] A magnetic recording medium layer provided on the substrate, a protective film made of a zirconium oxide film with a thickness of 100 to 1000 Å and containing 2 to 6 mol% of yttrium oxide, and information on the magnetic recording medium. A magnetic disk device equipped with a ferrite head that records or reproduces recorded information.