JPH05325161A - Magnetic head and magnetic disk apparatus - Google Patents

Abstract

PURPOSE:To restrain the attracting action of a magnetic head and that of a magnetic recording medium by a method wherein a coating layer, whose surface energy is low, is formed on the surface of a slider. CONSTITUTION:A magnetic-head slider face 11 is mirror-polished by using a polishing tape in such a way that its surface roughness in the center line becomes, e.g. 5nm. Thereby, a magnetic-head-slider base body is formed. The slider face 11 is coated with low-molecular polytetrafluoroethylene dissolving Flon 113; an organic-substance coating layer 12 which is composed of a fluoride is formed on the slider surface 11. Thereby, while a state that the surface roughness of the magnetic-head slider face 11 and that of a magnetic-disk surface are made smooth is being kept, the magnetic-head slider surface 11 is denatured by means of the coating layer 12 so that the attraction phenomenon of the magnetic-head slider face and that of the magnetic-disk surface are reduced. Thereby, a magnetic head whose low-levitation stability is excellent and which is suitable for a high-density recording operation is obtained.

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 high recording density magnetic disk device and a magnetic disk device using the magnetic head.

[0002]

2. Description of the Related Art So-called CSS (contact start stop)
In the magnetic disk device adopting the method, when the rotation of the magnetic disk is stopped, the slider surface of the magnetic head supported by the support member is pressed against the surface of the magnetic disk by spring force and is in contact therewith. Then, when the magnetic disk starts to rotate, the air flowing along the contact surface between the magnetic head and the magnetic disk gives buoyancy to the magnetic head and pushes up the magnetic head supported by the supporting member. At this time, the slider surface of the magnetic head slightly floats above the surface of the magnetic disk while the buoyancy and the spring force that presses the magnetic head against the surface of the magnetic disk are balanced.

The flying height of this magnetic head is currently about 0.2.
Since it is less than μm, it is expected to become smaller as the recording density increases in the future, and extremely high surface precision is required for the magnetic disk surface and the slider surface. For this reason, the surface of the magnetic disk has a center line average surface roughness of about 10 nm or less and is almost mirror-finished. In this way, a very narrow space is created at the contact interface between the extremely smooth magnetic disk and the magnetic head slider, and when the magnetic disk stops rotating, the water vapor in the atmosphere condenses at a lower vapor pressure. , Water will cause condensation. At this time, due to the surface tension, a strong attractive force is generated between the magnetic head and the magnetic disk, which causes a head attraction phenomenon in which the magnetic disk does not start rotating. It is also known that the surface of the magnetic disk is generally coated with a liquid lubricant, and this liquid lubricating film also causes the phenomenon that the attraction force increases and the magnetic disk does not start rotating due to the same action. ..

Therefore, US Pat.
As described in JP-A No. 840 and JP-A-61-29418, a fine groove called a texture is formed on a magnetic disk substrate to form a meniscus between the magnetic head and the magnetic disk when rotation is stopped. It has been proposed to suppress the attraction force between the magnetic head and the magnetic disk.

[0005]

In order to increase the recording density of a magnetic disk device in the future, it is necessary to reduce the flying height between the magnetic head and the magnetic disk, and especially 300M.
In order to achieve a recording density of b / in ² , the flying height should be 5
It should be about 0 nm. For that purpose, the textured surface roughness of the magnetic disk must be suppressed to a low level, and when the ideal surface is considered, the total surface roughness of the magnetic head slider and the magnetic disk must be 50 nm or less. In addition, the Journal of Tribological
Transactions ASME 111, p228
(J. Trib. Trans. ASME 111, 228 (198
According to 9)), as a stable flying condition of the magnetic head,
It has been reported that the flying height requires at least 6 times the surface roughness of the magnetic head slider and the magnetic disk surface. Considering this, the center line average roughness of the surface roughness of the magnetic head slider and the magnetic disk needs to be 8 nm or less. However, when the centerline average roughness of the magnetic head slider surface and the magnetic disk surface is set to 10 nm or less, an adsorption phenomenon occurs on the magnetic head slider surface and the magnetic disk surface,
Not only does it not function as a magnetic disk device, but in the worst case, the magnetic head may even be stripped from the support.

A first object of the present invention is to reduce the levitation amount of the magnetic head and the magnetic disk, while keeping the surface roughness of the magnetic head slider surface and the magnetic disk surface smooth while maintaining the magnetic head slider. It is an object of the present invention to provide a magnetic head which is excellent in low flying stability and suitable for high recording density by modifying the magnetic head slider surface so as to reduce the adsorption phenomenon between the surface and the magnetic disk surface. A second object is to provide a magnetic disk device using this magnetic head.

The meanings of the terms "center line average roughness" and "maximum height" used are based on the definitions stipulated in Japanese Industrial Standards (JIS-B0601).

[0008]

The first object of the present invention is to:
In the magnetic head slider arranged facing the magnetic disk, the surface energy of the magnetic head slider surface is changed by applying a surface modification treatment such as providing a coating layer made of an organic substance on the surface of the magnetic head slider. 78
It is achieved by making it smaller than dyn / cm. As the organic substance coated on the surface of the magnetic head slider, a fluorine-based material known as a material having a very low surface energy is preferable.

A second object of the present invention is a magnetic disk device having a magnetic disk rotation drive means, a magnetic head drive control actuator, and an input / output signal processing means connected to the magnetic head. The present invention is achieved by a magnetic disk device comprising the magnetic head of the invention.

[0010]

The requirement of the present invention is to suppress the surface roughness of the magnetic head slider surface and the surface of the magnetic disk in order to reduce the flying height so as to be suitable for high density recording, suppress the dew condensation phenomenon, and rotate the magnetic disk. This is to modify the magnetic head slider surface to reduce the surface energy of the slider surface in order to prevent the head adsorption phenomenon at the time of startup, which is realized by the following action.

The head adsorption phenomenon is caused by condensation of atmospheric water vapor in a very small space generated on the contact surface between the smooth magnetic head slider surface and the magnetic disk surface as described above, causing a so-called dew condensation phenomenon to cause meniscus. To form
This is a phenomenon in which a strong attractive force is generated between the magnetic head and the magnetic disk due to the action of wetting water with the surface of the magnetic head slider and the surface of the magnetic disk, and the surface tension, which prevents the magnetic disk from rotating.

Further, it is preferable that a thin lubricant is formed on the surface of the magnetic disk and the surface energy is made smaller than the surface tension of water, because the water is hard to get wet on the surface of the magnetic disk. Here, by making the surface energy of the magnetic head slider surface smaller than the surface energy of water, the magnetic head slider surface also becomes difficult to be wet with water. In other words, even if a meniscus occurs, the magnetic head slider surface and the magnetic disk surface are hard to get wet with each other.
The attractive force acting between them can be significantly reduced. Therefore, the surface modification can be realized by forming a fluorine-based organic substance having an adsorptive or adhesive property and a low surface energy surface on the magnetic slider surface.

The lubricant formed on the surface of the magnetic disk generally does not easily attract as a liquid,
When the lubricant becomes thicker, it is necessary to take into consideration the meniscus of the lubricant itself, and it is desirable that the film thickness is 5 nm or less. Further, by making the surface energy of the surface of the magnetic head slider smaller than the surface energy of the lubricant on the medium surface, adsorption of the lubricant itself can be suppressed, which is particularly preferable. The surface energy of fluorine-based perfluoropolyether, which is a commonly used lubricant for media, is 1
Since it is 5 to 20 dyn / cm 2, the surface energy of the magnetic head slider surface is preferably 15 dyn / cm or less. As a surface modifier for realizing such a surface, there is low molecular weight polytetrafluoroethylene perfluorodecanononanoic acid or the like.

[0014]

【Example】

<Example 1> A ceramic material mainly containing alumina titanium carbide having a thin film element for magnetic recording has a width of 2.
A magnetic head having the structure shown in FIG. 1 was prepared by cutting it out to a length of 4 mm, a length of 3 mm, and a height of 0.64 mm. The magnetic head slider surface 11 was mirror-polished with a polishing tape so that the center line average roughness was 5 nm, to form a magnetic head slider substrate. Low molecular weight polytetrafluoroethylene dissolved in Freon 113 was applied on the slider surface to form an organic coating layer 12 made of fluoride on the slider surface.

The surface energy of the surface of the magnetic head slider thus prepared was determined by measuring the critical surface energy by Zisman plot. Further, the strength of the head adsorption is determined by placing this magnetic head slider on a thin film magnetic disk having a carbon protective film and a lubricant layer of perfluoroalkyl polyether on the carbon protective film, and applying a head load of 10
g, ambient temperature 60 ° C, relative humidity 90%, leaving time 1h
Under the condition of r, the force required to move the magnetic head horizontally was measured and obtained.

Finally, the durability was evaluated by conducting a contact start / stop test and measuring the time when the torque received by the magnetic head was twice as high as that at the start of the test. These values are shown in Table 1.

Example 2 A magnetic head slider substrate prepared under the same conditions as in Example 1 was coated with Na salt of perfluoropolyether dissolved in CFC 113, and the slider surface was coated with an organic coating layer 12 of fluoride. Formed.
Such a magnetic head slider was evaluated under the same conditions as in Example 1.

<Embodiment 3> On the magnetic head slider substrate prepared under the same conditions as in Embodiment 1, an organic coating layer 12 made of fluoride was formed on the slider surface by a vacuum deposition method using perfluorodecanoic acid. Such a magnetic head slider was evaluated under the same conditions as in Example 1.

[0019]

[Table 1]

Comparing the first, second, and third examples with the comparative example, the surface energy of the slider surface is remarkably reduced in the first, second, and third examples, and as a result, the head attraction force is also remarkably reduced. I understand. Further, the durability is equal to or higher than that of Examples 1, 2, 3 and the comparative example, and it can be seen that there is no problem in durability. A ceramic material containing zirconia as a main component was used instead of the ceramic material containing alumina titanium carbide as a main component used in Examples 1, 2 and 3, and a coated magnetic disk was used instead of the thin film magnetic disk. However, the same effect was confirmed.

<Embodiment 4> A magnetic disk device as shown in FIG. 2 was constructed by combining the magnetic heads of Embodiments 1 to 3 with a sputter magnetic disk. By using the magnetic head slider of the present invention, even if the surface roughness of the magnetic head and the magnetic disk is made smooth, head adsorption can be prevented, and the flying height of the magnetic head and the magnetic disk can be narrowed. In comparison, it was possible to support high-capacity, high-density recording.

[0022]

The magnetic head according to the present invention is formed with an organic coating layer on the slider surface and the slider surface is modified to reduce the flying height of the magnetic head and the magnetic disk for high density recording. Even if the slider surface and the magnetic disk surface are made smooth, the adsorption phenomenon between the magnetic head slider surface and the magnetic disk surface can be prevented.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a cross-sectional structure of a magnetic head according to the present invention.

FIG. 2 is an explanatory diagram showing a cross-sectional structure of a magnetic recording device according to the present invention.

[Explanation of symbols]

 11 ... Coating layer, 12 ... Magnetic head.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akira Ishikawa Akira Ishikawa, Kokubunji, Tokyo 1-280, Higashi Koikeku Central Research Laboratory, Hitachi, Ltd. Inside the Central Research Laboratory (72) Inventor Yasuo Yaku 1-280 Higashi Koigokubo, Kokubunji City, Tokyo Inside Hitachi Central Research Laboratory (72) Inventor Tomo Yamamoto 1-280 Higashi Koigokubo, Kokubunji City, Tokyo Hitachi Central Research Institute In-house (72) Inventor, Yuzuru Hosoe 1-280 Higashi-Kengokubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (6)

[Claims] 1. In a structure comprising a magnetic head arranged facing a magnetic recording medium having a continuous thin film of ferromagnetic metal, the surface energy of the outermost surface of the head slider surface is 20 dy.
A magnetic head characterized by being n / cm or less. 2. A structure comprising a magnetic head arranged facing a magnetic recording medium in which magnetic particles are dispersed in an organic binder, wherein the surface energy of the outermost surface of the head slider surface is 20 dyn / cm or less. Characteristic magnetic head. 3. The magnetic head according to claim 1, which has a fluorine-based organic coating layer on the outermost surface of the magnetic head slider surface. 4. The magnetic head according to claim 1, wherein the magnetic recording medium has a carbon protective film. 5. The magnetic recording medium according to claim 1, wherein the center line surface roughness is 8 nm or less and the maximum surface roughness is 100.
A magnetic head that is nm. 6. The method according to claim 1, 2, 3, 4 or 5.
A magnetic disk device comprising: a rotation driving means for a magnetic disk; a drive control actuator for driving the magnetic head; and an input / output signal processing means connected to the magnetic head.