JPH0644547A - Floating type magnetic head - Google Patents

Abstract

PURPOSE:To provide a floating type magnetic head which is superior in productivity and low in cost and suitably mass-production by decreasing the area of contact with a magnetic recording medium, and reducing the dynamic frictional resistance and greatly improving CSS characteristics. CONSTITUTION:The floating type magnetic head consists of the phase of an oxide which has 350-800 (kgf/mm<2>) surface hardness at a 160nm depth from the surface and the phase of an oxide which has 600-1000 (kgf/mm<2>) surface hardness. The former phase is several tens - 1000Angstrom recessed below the latter phase in the surface facing the magnetic recording medium, more than 1.5 pieces of >=50Angstrom depth present on the surface roughness curve of a contact type surface roughness gauge at a 55mum distance, and a barrel shape having a >=200Angstrom height difference in the longitudinal direction of a floating surface and a >=40Angstrom height difference in a sectional direction is formed.

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, and more particularly to a floating magnetic head suitable for a small hard disk drive using a thin film medium.

[0002]

2. Description of the Related Art In recent years, a floating magnetic head levitation system in a small hard disk drive has been designed so that the floating magnetic head stops on the magnetic recording medium as the magnetic recording medium stops / rotates, and a fixed interval (hereinafter referred to as "magnetic recording medium") from the magnetic recording medium. Flying height and description)
CSS (contact start / stop)
The method is adopted. Also, in recent years, high density recording of magnetic disk devices has been studied especially by reducing the flying height, and various improvements and developments have been made to further reduce the flying height. Is a surface hardness of 600 to 1400 (kgf / mm ^{2 at} 160 nm from the surface).
) Or a mixture of phases containing CaTiO ₃ and SrTiO ₃ as main components, or a surface hardness at 160 nm from the surface of 5
00-900 (kgf / mm ² ) {mainly 500-760 (kgf / mm ²
) (The unit of hardness is omitted below)}
Ferrite phase oxide ceramics have been developed.

The surface of the floating magnetic head facing the magnetic recording medium is processed by a wet lap using diamond particles in the case of a magnetic head called a composite head composed of the non-magnetic ceramic slider and the core. ing. A monolithic head composed of Mn-Zn ferrite is formed by a similar wet lap method or a reverse sputtering method as disclosed in JP-A-1-251308.

However, in the composite head, along with this electromagnetic conversion characteristic, the extremely important CSS characteristic is bad and is a serious problem.

In particular, in the present and future environments in which the flying height becomes smaller and smaller, and the flattening of the thin film medium surface is required, the improvement of CSS characteristics becomes more important.

Therefore, improvements in slider ceramics materials and surface textures have been considered, and in terms of surface textures, it is considered effective to roughen the opposing surfaces to some extent from the viewpoint of reducing the contact surface with the magnetic recording medium. Maybe
For example, in the above-mentioned Japanese Patent Laid-Open Publication, it is suggested to apply a method in which minute unevenness is formed on the head surface by a reverse sputtering method.

[0007]

However, in the above-mentioned conventional structure, there is a problem that processing with coarse particles causes scratches, and the method using the reverse sputtering method has three types of materials each having different physical properties. That is, since the non-magnetic slider ceramics, the Mn-Zn ferrite core, and the glass are used, there is a problem in terms of applicability and workability. That is, since the physical etching rate of the glass and the Mn-Zn ferrite core is higher than the etching rate of the slider material, the etching amount of these two materials is large and the two materials are recessed more than the slider surface. In particular, the glass dent was as large as 5000 Å, which was basically a problem from the viewpoint of core strength. Therefore, there is a problem in that productivity is inferior because a process with poor workability, that is, masking the glass and the Mn-Zn ferrite core portion completely is indispensable.

In addition, the presence of minute inorganic dust or organic matter causes the same nonuniform etching rate, making it impossible to control the amount of irregularities, or in some cases, CS.
There is a drawback that a protrusion that causes a head crash is generated at the time of S, and therefore, there is a problem that a complete cleaning and an expensive dustproof facility are required at the time of manufacturing, and mass productivity is poor.

Further, in non-magnetic ceramics, M
Unlike n-Zn ferrite, there is a problem that it is difficult to form unevenness even by the reverse sputtering method and the CSS characteristics cannot be improved.

The present invention solves the above-mentioned problems of the prior art. The contact area with the magnetic recording medium is reduced and the shape is maintained to maintain a flexible contact state, thereby significantly improving the CSS characteristics and workability. It is an object of the present invention to provide a floating magnetic head which is excellent in productivity and low in cost and suitable for mass production.

[0011]

To achieve this object, the floating magnetic head of the present invention has a surface hardness of 350 to 800 (kg) at a hardness of 160 nm from the surface.
f / mm ² ) oxide phase and surface hardness 600-100
A floating magnetic head using a ceramic material composed of an oxide phase having 0 (kgf / mm ² ) as a slider, the surface hardness of which is 3 at a surface facing a magnetic recording medium.
The phase having 50 to 800 (kgf / mm ² ) has the hardness of 600.
Tens to 100 compared to phases having ˜1000 (kgf / mm ² ).
On the surface roughness curve of a contact type surface roughness meter at 0 Å dents and a distance of 55 μm, there are an average of 1.5 dents with a depth of 50 Å or more, and when assembled, the shape of the air bearing surface is 150 Å in the longitudinal direction. Or more, preferably 200 Å or more, 30 Å or more, preferably 40
It has a structure that is shaped like a kamaboko with a height difference of Å or more.

[0012]

With this structure, it is possible to obtain a surface having a property of reducing the area of the portion in contact with the magnetic recording medium.
Further, since the contact portion with the magnetic recording medium is a semi-cylindrical shape, it is possible to make a flexible contact, and as a result, it is possible to reduce the flying height of the floating magnetic head and improve the CSS characteristics.

[0013]

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

FIG. 1 is a perspective view of a floating magnetic head of this embodiment before wet lapping, and FIG. 2 is a schematic view of a slider mirror surface of the floating magnetic head of this embodiment.

Reference numeral 1 is a Mn-Zn ferrite core, 2 is glass, 3 is an air bearing surface of a slider, 4 is a slider, and 5 is a gap.

This slider ceramic material is C
It is composed of oxides of a, Sr, Ti, P, Si, Zr, and Al, and its composition is CaTiO ₃ , SrTiO ₃ , TiO 2.
₂ , P ₂ O ₅ , SiO ₂ , ZrO ₂ , and Al ₂ O ₃ conversion composition, 42, 37, 14, ₂ , 1.5, ₃ , 0.
It is 5 mol%. Next, the surface hardness and the area occupancy at a depth of 160 nm from the surface of each part in the schematic view of the slider in FIG. 2 were measured. The results are shown in (Table 1).

[0017]

[Table 1]

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. The depth is set to 160 nm because the accuracy of the data is taken into consideration. Surface area occupancy is S of mirror surface
It was determined from the EM photograph.

As is clear from this (Table 1), the surface hardness of the slider ceramics material occupies 4.5% of the surface area and the surface hardness at 160 nm from the surface is 350.
The phase of the oxide having ~ 800, mainly 800-1000
It was found to be composed of an oxide phase having a surface hardness of 600-1000. The surface hardness of ferrite was 500 to 900 (mainly 500 to 760).

Next, using the slider ceramics material, the Mn-Zn ferrite core and the glass, a floating magnetic head shown in FIG. 1 was prepared, and diamond particles having an average particle diameter of 0.12 μm shown in (Table 2) were used. The two types of wet laps were used to mirror-finish the head surface, which is the contact surface with the magnetic recording medium.

[0021]

[Table 2]

Next, the surface texture of this contact surface was measured at a total of 10 points on each head with a stylus type surface roughness meter over a distance of 55 μm. Then assemble,
The shape of the air bearing surface was examined with a fine surface shape measuring instrument WYKO, and the CSS characteristics of the magnetic head were evaluated by measuring the CSS characteristics using a 3.5-inch hard disk. Further, as a comparative example, a similar composite head type head using ferrite as a slider using the method of reverse sputtering and the wet lap and ferrite shown in the above-mentioned Japanese Patent Laid-Open was prepared, and the same properties and shape analysis were performed. The CSS characteristics were evaluated. The measurement results of surface texture are shown in FIG.
FIG. 3A is a measurement diagram of the surface texture of the floating magnetic head of this embodiment, and FIGS. 3B, 4A, and 4B are the surfaces of the floating magnetic head of the comparative example. It is a measurement diagram of properties.
The results of the surface texture are shown in (Table 3).

[0023]

[Table 3]

The surface texture was measured by taking the measured values in a personal computer and analyzing them. For the stylus type surface roughness meter, a diamond stylus having a tip of 0.1 μm × 2.5 μm was used under the condition of a magnification of 1,000,000. The surface shape is measured approximately 45 μm from the ridgeline in the cross-sectional direction of the air bearing surface in consideration of accuracy.
(A total of about 90 μm on one air bearing surface) The removed portion was measured under the condition of a magnification of 2.5. The configuration of the used 3.5-inch hard disk is shown below.

Substrate: Aluminum Underlayer: Cr Magnetic layer: Co-Ni sputtered film Surface layer: Carbon sputtered layer and a fluorine-based liquid lubricant layer applied to the surface of the carbon layer Surface roughness of the disk; Ra≈100Å CSS test The disk drive conditions are 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 r / min Time required for stopping from steady rotation speed; 4 Second rotation and stop time between rotations: 1 second Regarding the shape of the air bearing surface, as is clear from FIG. 3, there was a large difference between the main processings. In the processing method used for the floating magnetic head of the present example, a recess having a depth of several tens to 1000 Å was present, and due to this recess, there was a clear concavo-convex shape.
On the other hand, in the wet lap of processing No. 2 used for the floating magnetic head of the comparative example, although there were recesses having a depth of several tens to 150 Å, there was no clear uneven shape. next,
As is clear from Table 3, in the floating magnetic head of this embodiment, 1.5 or more recesses were present on average in the roughness curve at the frequency of occurrence of the recesses having a depth of 50 Å or more. This number in the floating magnetic head of the comparative example is
The number was 0.3 to 0.8.

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

The surface texture of the air bearing surface of the ferrite head of the comparative example is as shown in FIG. The shape obtained by the reverse sputtering method is shown in FIG.
As is clear from (b), the average step was 70 Å, which was quite rough.

FIG. 5 is a schematic diagram showing the relationship between the roughness curve measured between a given surface A and B of the floating magnetic head of this embodiment using a contact type surface roughness meter and the phase structure. In the figure, the upper figure shows a plan view of the crystalline phase and the particle state of the partial broken line AB measured, and the concave portion in the cross section has the above-mentioned chemically different soft hardness as shown in the lower figure. It is presumed that the particles and the group of particles of the phase 1 have. That is, the concave portions are generated when the particles of phase 1 are worn more severely than the particles of the mother phase or phase 2 during processing, and the concave portion is the particle C having the lowest portion in the grains in FIG. There are cases of particles and groups of particles including, and there are cases of grain boundaries D between phases 1 in FIG. Therefore,
The concavo-convex shape obtained as a result of this is as described in JP-A 1-25513
It is not the unevenness having the grain boundary of each particle as a boundary as in JP-A-08, but the uneven shape generated between the phase 1 and the mother phase or the phase 2. As for the depth of the recess, the depth of the deeper recess was measured as shown in FIG.

FIG. 6 is a perspective view of the floating magnetic head of the present embodiment, but in the longitudinal direction showing the shape of the air bearing surface, it was a semi-cylindrical shape. However, with respect to the shape in the cross-sectional direction, only the floating magnetic head using Machining No. 1 has a clear kamaboko shape, and the floating magnetic heads No. 1 to 4 of this embodiment have a height difference of 40 Å or more. Was.

Next, CSS characteristics were examined. CSS
The evaluation of the characteristic is the number of revolutions 1 rp after 20,000 CSS.
It was measured by the average value μ of the dynamic friction coefficient μk between the disk of m and the floating magnetic head and the increase value Δμ of the dynamic friction coefficient in 20000 CSS and 1 CSS. The results are shown in (Table 4).

[0032]

[Table 4]

As is clear from this (Table 4), the floating magnetic heads No. 1 to 4 of the present embodiment, the floating magnetic heads No. 5 to 9 of the comparative example, and the floating magnetic head No. of the comparative example. .
Μ and Δμ between 10 and 11 ferrite heads
There were advantages and disadvantages in the characteristics. The ferrite head of the comparative example
In No. 11, it was confirmed by a differential interference microscope that the unevenness was worn and the unevenness disappeared after CSS.

That is, in the ferrite head, Δμ is as high as 2.5 in the above-mentioned Japanese Patent Laid-Open, and even in the processing No. 1, Δμ shows a value of 0.4, and μ20000 shows a large value of 0.62. It was On the other hand, in the floating magnetic head of the comparative example, Δμ is 0.27 to 0.68, μ20000
However, in the floating magnetic head of this embodiment, Δμ was extremely small at 0.16 or less, and the value of μ20000 was 0.
It was found to be extremely small as 36 or less and the quality was stable.

From these facts, it can be said that the CSS characteristics depend on the surface hardness, surface quality and surface shape of the contact surface with the magnetic recording medium. That is, even in the air bearing surface having the uneven surface texture, the surface hardness becomes important, and the hardness of 500 to 760, such as ferrite, is small, and the roughness as shown in the above-mentioned Japanese Patent Laid-Open is added. It was found that the air bearing surface itself was subjected to excessive wear. Therefore, it can be said that a hardness higher than that of ferrite is required. Further, considering that the CSS is a contact motion involving a subtle vibration of the floating magnetic head in any direction, the friction in this process has a small contact area and is gentle without disturbing the vibration of the floating magnetic head. Therefore, it is composed of a phase having a small hardness using Machining No. 1 from the three viewpoints that it has a proper hardness and a small contact area and does not hinder the vibration of the floating magnetic head. The portion becomes a concave portion and the depth is 50 Å or more, and the concave portion has an uneven shape having an average of 1.5 or more in the roughness curve.
It has been clarified that excellent CSS characteristics can be obtained by using a semi-cylindrical shape having a height difference of 0Å or more and a semi-cylindrical shape having a height difference of 200Å or more in the longitudinal direction.

The head of the present invention is a composite type magnetic head using a non-magnetic oxide as a slider, but if it has the hardness distribution, the unevenness and the surface shape, it can be made of a magnetic material such as ferrite. Obviously, it is also effective for a monolithic head using an oxide and other magnetic heads.

[0037]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a soft oxide phase having a surface hardness of 350 to 800 at a depth of 160 nm from the surface is formed by using the lapping method having excellent productivity using diamond particles. Surface hardness 600-1000
(Mainly 800 to 1000) A non-magnetic ceramic material uniformly dispersed between the phases of a hard oxide has a concave-convex shape in which the soft phase is a recess, and the surface shape has a height difference of 40 Å or more in the cross-sectional direction. With 2 in the longitudinal direction
As it is shaped like a kamaboko with a height difference of more than 00Å, it has an optimal hardness, a small contact area, and a small dynamic friction resistance. It has outstanding CSS characteristics, high workability, and high productivity. It is possible to realize a floating magnetic head with excellent mass productivity.

[Brief description of drawings]

FIG. 1 is a perspective view of a floating magnetic head of this embodiment before lapping.

FIG. 2 is a schematic diagram of a mirror surface of a slider of the floating magnetic head of this embodiment.

FIG. 3A is a measurement diagram of the surface properties of the floating magnetic head of this embodiment measured using a contact surface roughness meter. FIG. 3B is a comparative example measured using a contact surface roughness meter. Measurement diagram of surface texture of floating magnetic head

FIG. 4A is a surface texture measurement diagram of a floating magnetic head of a comparative example using ferrite measured by using a contact surface roughness meter. FIG. 4B is a measurement by a contact surface roughness meter. Drawing of surface texture of the floating magnetic head of the comparative example processed by the reverse sputtering method using the formed ferrite

FIG. 5 is an arbitrary surface A- of the floating magnetic head of this embodiment.
Schematic diagram showing the relationship between the phase curve and the roughness curve measured between B using a contact type surface roughness meter

FIG. 6 is a perspective view of the floating magnetic head of this embodiment.

[Explanation of symbols]

 1 Mn-Zn ferrite core 2 Glass 3 Air bearing surface of slider 4 Slider 5 Gap

Claims (1)

[Claims] 1. A phase of an oxide having a surface hardness of 350 to 800 (kgf / mm ² ) and a surface hardness of 600 to 1000 (kgf /) at a depth of 160 nm from the surface due to the difference in chemical composition and structure. mm ² ), which is a floating magnetic head using a ceramic material composed of an oxide phase having a surface hardness of 350 to 800 (kgf / mm ² ) on the surface facing the magnetic recording medium. Compared to the phase having the hardness of 600 to 1000 (kgf / mm ² ), the phase has a dent of several tens to 1,000 Å, and the average of the dents with a depth of 50 Å or more in the surface roughness curve of the contact surface roughness meter at a distance of 55 μm . The number of air bearing surfaces is more than 150 in the longitudinal direction when there are 5 or more and they are assembled.
A floating magnetic head, characterized in that it is formed in a semi-cylindrical shape having a height difference of Å or more, preferably 200 Å or more, and 30 Å or more, preferably 40 Å or more in the cross-sectional direction.