JPH05166319A - Floating type magnetic head - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] The present invention can be manufactured by a simple process, can improve contact start / stop characteristics, is excellent in reliability and productivity, and is suitable for mass production at low cost. And a floating magnetic head. [Structure] An inorganic compound phase having a surface hardness of 350 to 800 (kgf / mm ² ) and an inorganic compound phase having a surface hardness of 600 to 1000 (kgf / mm ² ) at a depth of 160 nm from the surface are formed. The surface of the slider of the floating magnetic head provided with the slider has a surface hardness of 350 to 800 (kgf / mm ² ) on the surface a facing the magnetic recording medium.
Compared with the phase of 1000 (kgf / mm ² ), it has a recess with a depth of several tens to 1000 Å and / or has a depth of 50 Å or more on the surface roughness curve of a contact surface roughness meter at a distance of 55 μm. It is configured to be processed into a shape having 1.5 or more, preferably 2 or more recesses on average.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floating magnetic head suitable for use in a small hard disk drive or the like using a thin film medium.

[0002]

2. Description of the Related Art In recent years, in a small hard disk device, a floating magnetic head is stopped on a magnetic recording medium when the magnetic recording medium is stopped so that the magnetic recording medium rotates and a fixed distance (hereinafter referred to as a flying height) from the magnetic recording medium. ) Contact start / stop (hereinafter referred to as CSS)
Abbreviated) method is adopted. Further, the high recording density is mainly made by reducing the flying height, and various efforts are made for that purpose.

A conventional floating magnetic head will be described below. The floating magnetic head has a surface hardness of 160 nm from the surface (having a depth of 160 nm is for improving the accuracy of data) is 600 to 1400 (kgf / mm ² ).
A magnetic head called a composite head, which is composed of a slider formed of a mixture of phases containing CaTiO ₃ and SrTiO ₃ as main components, a Mn—Zn ferrite core, and glass, is used. The surface of the floating magnetic head facing the magnetic recording medium is processed by wet soft metal lapping using a lapping plate made of fine diamond particles and tin.

However, the composite head produced by wet soft metal lapping has a poor head-disk friction and wear characteristic called CSS characteristic. In particular, as described above, it is required to reduce the flying height. It is a very important issue.

Therefore, as a method of improving the CSS characteristics of the composite head, it is effective to roughen the surface of the composite head facing the magnetic recording medium to some extent from the viewpoint of reducing the contact area with the magnetic recording medium, and coarse particles are used. The CSS characteristics are improved by a method such as lapping, a method using a reverse sputtering method disclosed in Japanese Patent Laid-Open No. 1-251308, and the like.

[0006]

However, the above-described conventional method of processing using coarse particles has a problem that scratches are generated, while the method using the reverse sputtering method has its applicability and workability. However, there is a problem that mass productivity is lacking. Especially in the composite head, three kinds of materials with different physical properties,
That is, it is composed of non-magnetic ceramics, Mn-Zn ferrite and glass, but since the physical etching rate of glass and Mn-Zn ferrite is higher than the physical etching rate of non-magnetic ceramics, these are largely scraped from the slider surface. In particular, the concave portion of the glass portion reaches 5000 liters, which is a serious problem in terms of core strength. In order to prevent this, the glass part and the Mn-Zn ferrite part must be completely masked and processed, which causes a problem that the number of working steps is increased and the productivity is greatly reduced. In addition, the presence of minute inorganic dust or organic matter causes similar non-uniformity of the etching rate, making it difficult to control the amount of unevenness.
At times, there are problems that projections that cause head crashes are likely to occur and that the quality is unreliable and that the product yield is low. Further, in the non-magnetic ceramic portion, on the contrary, there is a problem that the physical etching rate is extremely slow and it is difficult to generate unevenness even by the reverse sputtering method.

The present invention solves the above-mentioned conventional problems and provides a floating magnetic head which can be produced by a simple process, has improved CSS characteristics, is excellent in reliability and productivity, is low in cost, and is suitable for mass production. The purpose is to provide.

[0008]

To achieve this object, the floating magnetic head of the present invention has a surface hardness of 350 to 800 (k) at a hardness of 160 nm from the surface.
gf / mm ² ) The phase of the inorganic compound and the surface hardness is 600
What is claimed is: 1. A floating magnetic head comprising a slider having a phase of an inorganic compound of about 1000 (kgf / mm ² ), wherein the surface hardness of the slider faces the magnetic recording medium of 350 to
800 (kgf / mm ² ) phase has the surface hardness of 600 to 1000
Compared with the phase of (kgf / mm ² ), it has a recess with a depth of several tens to 1000Å and / or a recess with a depth of 50Å or more on the surface roughness curve of a contact surface roughness meter at a distance of 55 μm. Has an average of 1.5 or more, preferably 2 or more.

[0009]

With this configuration, the contact area of the floating magnetic head on the surface facing the magnetic recording medium can be reduced, and the CSS characteristics can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view of a floating magnetic head according to an embodiment of the present invention. Reference numeral 1 is a slider made of a non-magnetic material, 2 is Mn-Z made of Mn-Zn ferrite
Reference numeral 3 denotes an n-ferrite core, 3 is a glass for adhering the Mn-Zn ferrite core 2 to the slider 1, and a is a surface of the slider 1 which is processed to have an appropriate uneven shape and faces the magnetic recording medium.

Here, the following were adjusted as the non-magnetic material for the slider. Non-magnetic materials A and B are CaTi
O ₃ , SrTiO ₃ , TiO ₂ , P ₂ O ₅ , SiO ₂ , ZrO
₂ , a solid solution or a mixture of Al ₂ O ₃ , or a sintered body substantially composed of a compound consisting of its constituent elements, the main composition of which is CaTiO ₃ , SrTiO ₃ , TiO ₂ , P ₂ O
₅ , non-magnetic material A in terms of SiO ₂ , ZrO ₂ , Al ₂ O ₃
Then, 42,37,14,2,1.5,3,0.5 mol%
And in the non-magnetic material B, 43, 38, 14, 1,
It is 1, 2.7, 0.3 mol%.

Next, each of the non-magnetic materials A and B was fired to produce a slider. The manufacturing method of the floating magnetic head of the present embodiment having the above-described structure will be described below.

A floating type magnetic head manufactured by adhering the Mn-Zn ferrite core 2 to the slider 1 using the glass 3 is fixed on a processing jig (not shown). Then, using a processing machine in which fine diamond particles or the like are used as lapping abrasive grains and a highly elastic body such as acrylic resin is used as a lapping surface plate, the magnetic recording medium facing surface of the slider 1 is softly lapped to form a floating magnetic head. It was made.

(Experimental Examples 1 and 2) With respect to the floating magnetic head manufactured as described above, the surface hardness and the surface area occupation rate of the mirror-finished portion of the slider were examined.

FIG. 2 shows a schematic view of the mirror-finished portion of the slider. The surface hardness and the surface area occupation ratio at 160 nm from the surface of each part in this schematic diagram 2 were measured. The results are shown in (Table 1).

Experimental Example 1 was performed using a non-magnetic material A, and Experimental Example 2 was performed using a slider manufactured using a non-magnetic material B.

[0018]

[Table 1]

Here, the surface hardness was determined from the load at a maximum load of 1 gf and the insertion depth of the indenter using a dynamic hardness tester manufactured by Shimadzu Corporation. Surface area occupancy is SEM of mirror surface
It was determined from the photograph (× 2000).

As is clear from this (Table 1), the mirror surface of the slider using the non-magnetic materials A and B occupies 4.5% and 2% of the surface area, and the surface hardness at 160 nm from the surface is 350 to 800 (kgf / kgf / It was found to be composed of a mixture of an oxide phase of mm ² ) and an oxide phase of the surface hardness of 600 to 1000 (kgf / mm ² ).

(Experimental Examples 3 to 6) Next, the floating type magnetic head shown in FIG. 1 was produced using any one of the materials A and B, and lapping was performed under the following conditions to examine the surface shape. did.

The lapping plate made of acrylic resin was used, and the lapping abrasive grains had an average particle size of 0.12.
μm diamond particles were used. The number of rotations of the lapping plate was 40 rpm and 60 rpm. For each experimental example, 30 floating magnetic heads were manufactured.

Next, the surface shape of the machined surface was measured at a total of 10 points on the floating magnetic head of each experimental example by a stylus type surface roughness meter over a distance of 55 μm.

The surface shape of the machined surface was obtained by analyzing the measurement values by loading them into a personal computer. The stylus surface roughness meter was measured under the condition of a magnification of 1,000,000 using a stylus made of diamond and having a tip radius of 0.1 μm. The measurement results are shown in (Table 2).

[0025]

[Table 2]

Next, the surface shapes of the floating magnetic heads of Experimental Example 3 and Experimental Example 5 were measured by using a contact type surface roughness meter. The result is shown in FIG.

FIG. 3A is a graph of the roughness curve showing the surface shape of Experimental Example 3, and FIG. 3B is a graph of the roughness curve showing the surface shape of Experimental Example 5.

The floating magnetic heads of the respective experimental examples having the above surface shapes were assembled, the CSS characteristics were measured using a 3.5-inch hard disk, and the CSS characteristics of each floating magnetic head were evaluated.

The hard disk used for measuring the CSS characteristics is as follows. Substrate: Aluminum Underlayer: Cr Magnetic layer: Co-Ni sputtered film Surface layer: Carbon sputtered layer and fluorine-based solid lubricant layer applied to the surface of the carbon layer Surface roughness of the disk; Ra ≈ 55Å Disk drive condition at CSS test Is as follows.

Head pressure: 93 mN (9.5 gf) Measuring position: 25 mm Time required for steady rotation speed: 4 seconds Steady rotation speed and time: 1 second at 2300 rpm Time required for stopping from steady rotation speed: 4 seconds Rotation And stop time between rotations: 1 second The measurement results obtained by the above measurement are shown in (Table 3).

[0031]

[Table 3]

Μ is the number of revolutions 1 rp after CSS 20,000 times
The average value of the dynamic friction coefficient μk between the disk of m and the head, Δ
μ is an increase amount of the average value of the dynamic friction coefficient after one CSS and 20,000 CSS.

(Comparative Examples 1 to 4) A floating magnetic head was manufactured using the same material as the experimental example, and the magnetic recording medium facing surface a of the slider 1 was processed by a soft metal wrap.

The working method was the same as that of the experimental example except that a lapping plate made of tin was used, and 30 floating magnetic heads were produced for each comparative example.

Next, the surface shape of this processed surface was measured in the same manner as in the experimental example. The measurement results are shown in (Table 2).

Next, the surface shapes of the floating magnetic heads of Comparative Examples 1 and 3 were measured using a contact type surface roughness meter in the same manner as in the experimental example. The result is shown in FIG.

FIG. 4A is a graph of a roughness curve showing the surface shape of Comparative Example 1, and FIG. 4B is a graph of a roughness curve showing the surface shape of Comparative Example 3.

The floating magnetic head of each comparative example having the above surface shape was assembled, and the CSS characteristics were measured under the same conditions as the experimental example using a 3.5-inch hard disk. The results are shown in (Table 3).

As is clear from FIG. 3 and (Table 2), in the processed surfaces of the floating magnetic heads of Experimental Examples 3 to 6,
Regardless of the material and the number of rotations of the surface plate, a recess having a depth of several tens to 1000 Å and a clear uneven shape due to the recess were obtained. On the other hand, as is clear from FIG. 4 and (Table 2), on the machined surfaces of the magnetic heads of Comparative Examples 1 to 4, there were recesses having a depth of several tens to 150 Å, but clear concavo-convex shapes were obtained. There wasn't. Further, the frequency of occurrence of the recesses having a depth of 50 Å or more was different between the floating magnetic heads of the experimental example and the comparative example, and in the experimental examples, 1.5 or more recesses were present on the roughness curve on average. On the other hand, in the comparative example, the number was 0.3 to 0.8.

The recess is made of CaTiO ₃ , SrTi.
O ₃ and its solid solution or TiO ₂ or a trace amount of P, Si, Z
The composition is different from that of the mother phase in which r and Al are diffused.
It was a phase of oxides of Ti, Ca, Sr rich in Zr, Al.

Further, as is clear from (Table 3), in the floating magnetic head of the experimental example, the value of μ is 0.2 to
It was as small as 0.24 and stable. Further, the value of Δμ was almost 0 in all the experimental examples, indicating that the CSS characteristics were excellent. In particular, Δ of Experimental Examples 3 and 4 using the material A
It was found that the value of μ is negative and has extremely high CSS characteristics.

On the other hand, in the floating magnetic head of the comparative example, the value of μ is as large as 0.28 to 0.36, and the value of Δμ is as large as 0.06 to 0.17.
It was found that the S characteristics were inferior.

Next, the relationship between the phase structure of the slider used in the present invention and the roughness curve will be described.

FIG. 5 (a) is a schematic view showing the crystal phase and the state of particles on the processed surface, and FIG. 5 (b) is a view of A in FIG. 5 (a).
It is a schematic diagram which shows a -B cross section.

H1, H2 and H3 are the depths of the recesses, C is the grain at the bottom of the recess, and D is the grain boundary between phases 1 at the bottom of the recess.

The recess in the cross section of FIG. 5A is shown in FIG.
As shown in (b), it is presumed to be particles and a group of particles of phase 1 having a chemically different composition and having a soft hardness. That is, the concave portions are generated when the particles of phase 1 are worn more severely than the particles of mother phase or phase 2 during processing. Regarding the position of the concave portion, the particle C having the lowest part in the particle
There are cases of particles and groups of particles containing, and there are cases of grain boundaries D between phases 1. Therefore, the uneven shape obtained as a result is not the uneven shape having the grain boundary of each particle as a boundary as described in JP-A-1-251308, but the uneven shape generated between the phase 1 and the mother phase or between the phases 2. That is why. Here, the depth of the concave portion is deep as shown in FIG.

Although the slider of the floating magnetic head in this embodiment is an oxide made of a non-magnetic ceramic material, it may be an inorganic compound other than the oxide as long as it has the above hardness distribution. It may also be magnetic ceramics. Further, it may be an inorganic compound having the hardness distribution described above and containing one or more phases of hardness other than the above.

As described above, according to this embodiment, the slider having the two phases of high hardness and low hardness is used.
By manufacturing a floating magnetic head and processing the surface facing the magnetic recording medium with a soft wrap or the like to form an appropriate unevenness, the contact area on the processed surface with the magnetic recording medium is reduced, and the CSS characteristics Can be dramatically improved.

[0049]

As described above, the present invention has a surface hardness of 350.
A floating magnetic head comprising a slider having two phases, an inorganic compound phase having a surface hardness of ~ 800 (kgf / mm ² ) and an inorganic compound phase having a surface hardness of 600 to 1,000 (kgf / mm ² ). The surface having a surface hardness of 350 to 800 (kgf / mm ² ) is several tens to one as compared with the surface hardness of 600 to 1000 (kgf / mm ² ) by a soft wrap or the like on the surface facing the magnetic recording medium.
000 Å dents, the surface roughness curve of a contact type surface roughness meter at a distance of 55 μm is processed into a shape such that there are an average of 1.5 or more recesses with a depth of 50 Å or more, and A floating magnetic head that can reduce the contact area with the recording medium and dramatically improve the CSS characteristics, has a simple process, has excellent productivity, reliability, and durability, is low cost, and is suitable for mass production. It can be realized.

[Brief description of drawings]

FIG. 1 is a perspective view of a floating magnetic head according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of mirror surfaces of materials A and B.

3A is a graph of a roughness curve showing a surface shape of a machined surface in Experimental Example 3; FIG. 3B is a graph of a roughness curve showing a surface shape of a machined surface in Experimental Example 5;

4A is a graph of a roughness curve showing a surface shape of a machined surface in Comparative Example 1. FIG. 4B is a graph of a roughness curve showing a surface shape of a machined surface in Comparative Example 3.

5A is a schematic diagram showing a crystal phase and a particle state of a processed surface. FIG. 5B is a schematic diagram showing an AB cross section in FIG. 5A.

[Explanation of symbols]

 1 Slider 2 Mn-Zn Ferrite Core 3 Glass a Surface of slider facing magnetic recording medium C Grain that is the lowest part of the recess D D Grain boundary between phases 1 that is the lowest part of the recess H1 Depth of recess H2 Depth of recess H3 Depth of recess

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Junichi Kimura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A phase of an inorganic compound having a surface hardness of 350 to 800 (kgf / mm ² ) at a depth of 160 nm from the surface and the surface hardness of 600 to 1000 (kgf / m ² ).
m ² ), a floating magnetic head provided with a slider having a phase of an inorganic compound, the surface hardness of 350 to 800 (kgf / mm ² ) on the surface of the slider facing the magnetic recording medium.
Has a recess with a depth of several tens to 1000 Å as compared with the phase having a surface hardness of 600 to 1000 (kgf / mm ² ), and / or a surface roughness curve in a contact type surface roughness meter at a distance of 55 μm. A floating magnetic head having an average of 1.5 or more, preferably 2 or more recesses with a depth of 50 Å or more on the top.