JPH0757230A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To improve the wear resistant strength of the magnetic recording medium-facing surfaces of the magnetic head, of which the recording medium- facing surfaces are formed of a polycrystalline magnetic material and to form these recording medium-facing surfaces to adequate surface roughness. CONSTITUTION:This magnetic head H comes into contact with the surface of a hard disk while this disk is held stopped. The magnetic head floats from the disk when the disk rotates. The crystal faces of a Miller index (110) having the high wear resistant strength of individual crystal grains C1, C2,... are deposited by the rail surfaces 11a, 11b of a slider 11 formed of the polycrystalline material of an Mn-Zn ferrite system of such magnetic head H. The wear resistant strength of the rail surfaces 11a, 11b is, therefore, enhanced and the adequate surface roughness is generated by the rail surface 11a, 11b by which the true contact area with the stopped disk is made adequate. An increase in the starting torque of the disk is thereby prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head having a surface facing a magnetic recording medium made of a polycrystalline material, such as a levitation type magnetic head mounted in a hard disk drive. The present invention relates to a magnetic head which has improved wear resistance of its surface and has an opposing surface having an appropriate surface roughness, and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 10 is a side view showing a floating magnetic head H used in a hard disk drive and a part of a supporting mechanism thereof. In the floating magnetic head H shown in FIG. 10, a C-shaped core 2 is joined to the end of the slider 1, and a magnetic gap G is formed at the joint between the slider 1 and the core 2. A coil 3 is wound around the core 2. The magnetic head H is, for example, a monolithic type, and the slider 1
The core 2 and the core 2 are both formed of a Mn-Zn ferrite-based polycrystalline material. The support mechanism 4 for supporting the magnetic head H is provided with a load beam 5 having bent pieces 5a formed on both edges, and a flexure 6 formed of a thin leaf spring material is provided on the lower surface of the tip of the load beam 5. It is fixed. A tongue piece 6a is integrally formed on the flexure 6, and the slider 1 is adhesively fixed to the lower surface of the tongue piece 6a. Further, a spherical-shaped projection 6b is formed so as to bulge almost at the center of the tongue piece 6a. The tip of the protrusion 6b contacts the lower surface of the load beam 5, and the tongue 6a and the magnetic head H adhered to the tongue 6a can move freely with the pivot support of the protrusion 6b as a fulcrum.

10 and 11 show the relationship between a magnetic head and a disk in a CSS (contact start / stop) type hard disk device. This CS
In the S method, when the hard disk D is stopped, the magnetic head H moves to the standby area of the inner diameter portion of the disk, and the elastic force exerted by the spring portion at the base of the load beam 5 at this position causes the magnetic head to move. H is pressed against the surface of the disk D by force F. When the disk D starts to rotate,
An airflow that flows with the rotation of the disk D enters between the lower surface of the slider 1 and the disk D, and the magnetic head H moves to the position shown in FIG.
It floats from the disk surface in the posture as shown in FIG. In this levitating attitude, the magnetic gap G and the surface of the disk D are set to have an optimum distance, and data is written to the disk D or data is read from the disk by the magnetic gap G.

[0004]

In this type of floating magnetic head, as shown in FIG. 10, the magnetic head H is pressed against the surface of the disk D by the force F when the disk D is stopped. ing. Therefore, when starting the disc,
A load torque for causing the slider 1 and the disk D to start sliding is generated. The load torque is a frictional force generated by an adhesive force, a surface tension of a liquid film interposed between the slider 1 and the disk D due to moisture or a liquid lubricant, an attraction force, and the like. The load torque due to this friction is related to the true contact area between the slider 1 and the disk D. When the disk facing surface of the slider is rough and the true contact area is small, the load torque is reduced, and the surface roughness of the facing surface is small and the true contact is small. If the area is large, the load torque increases.

Further, as shown by the chain line in FIG. 12, in the case where the surface of the slider 1 is given an appropriate surface roughness and initially set so that the actual contact area with the disk D becomes small. Even if the disk starts and stops repeatedly, the surface of the slider 1 gradually wears as shown by the solid line, which also increases the true contact area with the disk D. In particular, the slider 1 formed of the Mn-Zn ferrite-based polycrystalline material cannot be said to have sufficient wear resistance, and an increase in the true contact area due to wear cannot be avoided.

Therefore, when the conventional floating magnetic head is used to repeatedly start and stop the disk, the load torque for starting the disk increases as the number of repetitions increases. Recently, the surface roughness of the disk tends to decrease due to high-density recording of data, but when a disk with a small surface roughness is used, the true contact area with the disk is reduced due to wear of the slider. Increase sharply. Therefore, the increase in load torque due to repeated start and stop is significant, and for example, start and stop are
When it is repeated about 0000 to 40,000 times, the load torque acting on the disk at the time of startup exceeds the output torque of the disk drive motor, and the disk cannot be started.

The present invention is to solve the above-mentioned conventional problems, and when it is formed of a polycrystalline material such as Mn-Zn ferrite material, the abrasion resistance strength of the surface facing the magnetic recording medium is increased, Moreover, it is an object of the present invention to provide a magnetic head capable of obtaining an appropriate surface roughness and a manufacturing method thereof.

[0008]

According to the present invention, in a magnetic head having a surface facing a magnetic recording medium made of a polycrystalline magnetic material, a crystal having excellent wear resistance of individual crystal grains of the polycrystalline material. A surface is exposed on the facing surface.

The magnetic material is, for example, a Mn-Zn ferrite system, and the crystal faces of the individual crystal grains having the Miller index (110) appear on the facing faces.

In the method of manufacturing a magnetic head according to the present invention, the surface facing the magnetic recording medium is abraded with abrasive grains, or the surface facing the magnetic recording medium is subjected to chemical etching or physical etching. In this case, a crystal plane having excellent wear resistance of individual crystal grains of a polycrystalline material is deposited.

In the polycrystalline material, the orientation of the individual crystal grains is different. However, when attention is paid to the individual crystal grains, the wear resistance strength of the crystal plane of a certain orientation is higher than that of other crystal planes. ing. For example, in a Mn-Zn ferrite-based polycrystalline material,
The wear resistance strength of the crystal plane of each crystal grain in the orientation of Miller index (110) is significantly higher than that in the crystal plane of the orientation of (111).

Therefore, in the magnetic head of the present invention, a crystal face having excellent wear resistance of individual crystal grains of the polycrystalline material is deposited on the face facing the magnetic recording medium. Therefore, the wear resistance strength is remarkably improved in a constant area or the entire area of the facing surface. Also, by exposing the crystal surface with high wear resistance in each crystal grain, the surface roughness of the surface of the facing surface can be set to an appropriate level. For example, when a slider of a floating magnetic head is formed, the actual contact with the disk is made. The area can be set appropriately.
Even when the magnetic head is repeatedly contacted and levitated on the disk by repeating the start and stop of the disk, abrasion is less likely to occur due to the high abrasion resistance of the facing surface, and therefore the start and stop are repeated. However, the real contact area between the magnetic head and the disk does not increase, and the load torque at the time of starting the disk increases only slightly.

As a means for depositing the crystal surface of the polycrystalline material having excellent wear resistance as described above, the surface of the polycrystalline material is first polished so as to be a mirror surface, and then the silica abrasive grain is used. It can be realized by performing low-energy wear work using, for example. Alternatively, the surface of the polycrystalline material may be subjected to physical etching such as reverse sputtering or ion milling, or chemical etching to deposit a crystal plane having excellent wear resistance of individual crystal grains.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 2 is a perspective view showing a levitation type magnetic head used in a hard disk device with a surface facing a disk facing upward, and FIG. 3 is a partial enlarged view showing a magnetic gap portion of the levitation type magnetic head of FIG. 1 and 2 are partially enlarged cross-sectional views of the floating magnetic head shown in FIG. The flying magnetic head H shown in FIG. 2 is a two-rail type, and the slider 11 and the I-shaped core 12 joined to the slider 11 are both formed of a polycrystalline material of Mn—Zn ferrite system. Slider 11
The air groove 11c is formed in the center of the surface (the upper surface in FIG. 2) facing the disk of the air groove 1.
Two rail surfaces 11a and 11b are formed on both sides of 1c. A groove 1d is formed on the front end surface of the slider 11.

As shown in FIG. 3, the I-shaped core 12 is joined to the front side of one rail surface 11a of the slider 11, and the opposed surfaces of the slider 11 and the core 12 are made of soft magnetic material having high magnetic permeability. The magnetic metal films 13 and 14 are laminated. Both soft magnetic metal films 13 and 14 are made of glass material 15.
And the magnetic gap G is formed. 2 and 3, the nonmagnetic material layer 16 is formed on the front surface of the core 12. A coil is wound around the core 12 and the non-magnetic material layer 16, but the impedance can be reduced by providing the non-magnetic material layer 16.

Rail surface 11a of the floating magnetic head H
The condition of the surfaces of and 11b is shown in FIG. As shown in FIG. 1, among the crystal grains of the Mn—Zn ferrite-based polycrystalline material, the crystal grains C1, C2, C3, ... Appearing on the rail surfaces 11a, 11b are all provided with a Miller index ( The crystal plane of 110) appears. Rail surface 11
a, 11b of each crystal grain C1, C2, C3 ,.
As a result of the appearance of the crystal plane of 0), the rail surfaces 11a and 11
Moderate surface roughness occurs on the surface of b, and due to this surface roughness,
The true contact area when in contact with the disc is set appropriately. The degree of this surface roughness becomes smaller or larger depending on the grain size of the polycrystalline material. Further, in the Mn-Zn ferrite-based crystal grains, the wear resistance strength of the crystal face having the Miller index (110) is very high. Therefore, as shown in FIG. 1, the (110) crystal face of each crystal grain is present on the surface. As a result, the wear resistance strength of the rail surfaces 11a and 11b is increased. In this embodiment, the area indicated by A in FIGS. 1 and 3, that is, the area including the magnetic gap G has a smooth surface irrespective of the orientation of the crystal plane.

As shown in FIG. 1, the rail surfaces 11a, 11
Since b has an appropriate surface roughness and the abrasion resistance is high, the torque required for starting the disk becomes appropriate, and the disk is repeatedly started and stopped to repeat the rail surfaces 11a and 11b and the disk. Even if the contact with D and the floating are repeated, it is possible to prevent an increase in the true contact area due to wear, and the load torque applied to the disk D does not increase.

Next, rail surfaces 11a, 1 as shown in FIG.
A method of manufacturing the magnetic head H having 1b will be described. (Manufacturing Method I) First, by polishing work, the rail surface 11a,
An attempt was made to deposit the (110) plane on 11b. Mn
In the case of -Zn ferrite-based polycrystalline material, (11
Since wear tends to occur when orientations other than the (0) plane appear, polishing with low energy allows the surfaces of the rail surfaces 11a and 11b to have high wear resistance (11).
Only the 0) plane can be preferentially oriented. The steps of the polishing operation actually performed are as follows.

(1) The rail surfaces 11a and 11b and the portion where the magnetic gap G is exposed are polished so as to have a smooth surface. In this polishing work, a tin surface plate is coated with a slurry containing diamond grains, and the rail surfaces 11a and 11b of the magnetic head having the shape shown in FIG.
The magnetic head was rotated, and the surface plate was rotated to perform polishing. In the polishing work using the diamond slurry, the polishing is finished to have a smooth surface regardless of the plane orientation of the crystal grains appearing on the surfaces of the rail surfaces 11a and 11b.

(2) Next, a non-woven fabric is placed on the surface of the surface plate. For the actual polishing, a product name "polishing cloth" manufactured by Nippon Engis Co., Ltd. was used. Abrasive grain size is 500
Silica abrasive grains of Angstrom or less were used, and this was dissolved in pure water to form a colloidal shape, which was sprinkled on the non-woven fabric. The magnetic head H masks the area indicated by A in FIGS. 1 and 3, that is, the area in which the magnetic gap G is provided, and the rail surfaces 11a and 11b are applied to the non-woven fabric to rotate the magnetic head and rotate the surface plate. Then, the polishing work was performed. This polishing is low-energy polishing, and as a result, as shown in FIG. 1, each of the crystal grains C1, C2, C3 ,.
0) surface was deposited.

FIG. 4 shows the surfaces of the rail surfaces 11a and 11b actually obtained by the above polishing work. This is the atomic force microscope AFM for the polished rail surfaces 11a and 11b.
(Atomic Force Microscope), and FIG. 4 illustrates what is displayed on the CRT and output by the plotter. In the example shown in FIG.
The grain size of the Mn-Zn ferrite-based polycrystalline material is 15 to 2
It is about 0 μm, and as shown in FIG. 1, the maximum depth of the recess is about 40 nm. In addition, the rail surface 11a,
When the center line average roughness Ra of 11b was measured, Ra was 4
It was about 7 nm. The abrasive grains used in the polishing operation (2) may be sapphire abrasive grains. Further, artificial leather or the like can be used instead of the non-woven fabric.

(Manufacturing Method II) Further, an attempt was made to deposit (110) planes of crystal grains on the rail surfaces 11a and 11b by reverse sputtering. "SPF-730" manufactured by Anerva Co. was used as a sputtering device. In the magnetic head H, first, the rail surfaces 11a and 11b and the magnetic gap G are finished to be smooth surfaces by the polishing operation of (1). Next, the area indicated by A in FIGS. 1 and 3 was masked and this was placed in the chamber of the sputtering apparatus. The inside of the chamber was replaced with 100% argon gas, and the pressure was set to 7 mtorr. Sputtering output is 300W
The sputtering time was 10 to 30 minutes. As a result, as in the case of (2) of the polishing operation, rail surfaces 11a, 11 in which (110) is preferentially oriented on the surface are obtained.
b could be obtained. In this reverse sputtering, low energy is applied to the rail surfaces 11a and 11b to leave the (110) plane, but similarly, other physical etching such as ion milling or chemical etching may be used. It is possible.

Next, it was manufactured as described above (11
The wear resistance of the magnetic head having the rail surfaces 11a and 11b in which the (0) surface is preferentially oriented was tested. The results are shown below. [Abrasion resistance test] FIG. 6 shows the results of the abrasion resistance test.
(Sample 1) to (Sample 4) were used for this abrasion resistance test.

(Sample 1) A magnetic head in which the rail surfaces 11a and 11b obtained by the polishing operation of the manufacturing method I have a preferential orientation of the (110) surface, and the surface state of the rail surface is shown in FIG.
Shown in. The overall structure of the head is as shown in FIG.

(Sample 2) A magnetic head having the same shape as that of Sample 1, in which the slider 11 is made of an Mn-Zn ferrite-based polycrystalline material and the rail surfaces 11a and 11b are polished smoothly (the above-mentioned polishing). Work (1)).

(Sample 3) A slider having the same shape as that of Sample 1 is formed of a ferrite single crystal material.
The orientation of the crystal plane of the rail surface is (110).

(Sample 4) A slider having the same shape as that of Sample 1 is formed of a ferrite single crystal material.
The orientation of the crystal plane of the rail surface is (111).

In this test, a 1.2 m long CrO ₂ coated tape was used, the rail surface of each sample was applied to this magnetic tape and pressed so that the tape tension was 250 g, and the tape and the sample were 125 inches. It was slid at a speed of / sec. One slide of each sample with respect to the magnetic tape
Number of slides. In FIG. 6, the horizontal axis indicates the number of slides on a logarithmic axis, and the vertical axis indicates the wear depth of the rail surfaces 11a and 11b (μ
m) is shown. As shown in this diagram, in the sample 4 using the single crystal material having the plane orientation (111), the abrasion amount remarkably increases due to repeated sliding, and in the sample 2 using the polycrystalline material as it is. It can be seen that the amount of wear is increasing. On the other hand, according to the above embodiment (11
In the sample 1 in which the crystal plane of (0) is precipitated, the plane orientation is (11
It can be seen that it has wear resistance strength equivalent to that of the single crystal material of 0).

[CSS Repeating Test] Next, the magnetic head according to the present invention and the conventional magnetic head were mounted on a CSS type hard disk device, and a repeating test of starting and stopping the disk was conducted. The following (Sample a) to (Sample i) were used in this test. (Sample a) to (Sample c)
According to the manufacturing method I (polishing work), the rail surfaces 11a, 1
A magnetic head in which a (110) crystal plane is deposited on 1b,
(Sample d) to (Sample f) were formed on the rail surfaces 11a and 11b by the manufacturing method II (reverse sputtering) (11
This is a magnetic head in which the crystal plane 0) is deposited. In addition, (Sample g) to (Sample i) are sliders 11 formed of a polycrystalline material of Mn—Zn ferrite system as a comparative example, in which the plane orientation of the rail surface is random, that is, a conventional magnetic head. Further, in (Sample g) to (Sample i), the center line average roughness Ra of the rail surfaces 11a and 11b is 4 to 7n.
m, and the surface roughness was the same as that of (Sample a) to (Sample f).

In the experiment, a commercially available 3.5 inch sputter disk for high density recording was used. According to the standard of this disc, the center line average roughness Ra of the surface is about 9.5 nm,
The glide height (Gh) is 2.5 micro inches. Fluorocarbon type lubricant is 1.2n on the surface.
What was applied in the thickness of m was used. What was used in the experiment was a normal hard disk device using two magnetic heads, and the capacity of the disk drive motor mounted on this was a maximum output torque of 70 g · cm. Each of the above (Sample a) to (Sample i)
As shown in FIG. 5, it was supported by a common standard load beam 5 and flexure 6. The force F by which the magnetic head was pressed against the disk D by this support mechanism was 9.5 g.

In the experiment, only one magnetic head as a sample was mounted on one side of the disk D, and the magnetic gap G of the magnetic head was located at a position 20 mm away from the center of rotation of the disk as shown in FIG. installed. Then, the disk D was repeatedly started and stopped, the number of repetitions was measured, and the torque required to start the disk from the motor current was measured.

FIGS. 7A to 9C show CSS.
(Contact start / stop) The results of repeated tests are shown. In each of these figures, the horizontal axis represents the number of times the disk is started and stopped, and the vertical axis represents the torque (g · cm) required to start the disk. As described above, since only one magnetic head is mounted on one side of the disk D in this experiment, the maximum set torque of the motor is 3
The evaluation was performed with 5 g · cm.

FIGS. 7A, 7B, and 7C show the test results of Sample a, Sample b, and Sample c in which the (110) plane is preferentially oriented by the manufacturing method I, and FIGS. B)
(C) shows the test results of the sample d, the sample e, and the sample f in which the (110) plane is preferentially oriented by the manufacturing method II. According to the test results shown in FIGS. 7 and 8, even if the disk is repeatedly started and stopped 300,000 times, the torque required for the start is slightly increased. This torque is the maximum set torque of the motor (35 g).・ Cm).

FIGS. 9A, 9B and 9C show the test results of sample g, sample h and sample i in which the (110) plane is not preferentially oriented. From this result, it can be seen that the torque required for start-up sharply increases due to repeated start-up and stop of the disk. In the case of sample g, 42810 times, sample h, 25660 times, and sample i, the disk could not be started at the 31810th disk start. That is, the load torque of the disk due to the contact of the magnetic head due to the number of repetitions is the maximum set torque of the motor (35 g
・ Cm) is exceeded.

As described above, in each of the samples a to i, the slider 11 is made of the same Mn-Zn ferrite-based polycrystalline material, and the rail surfaces 11a and 11b have substantially the same center line average roughness Ra. Samples a to f, which are examples of the present invention, are
~ It can be seen that the number of times of endurance by CSS repetition is significantly improved as compared with the sample i. That is, in the conventional slider using the polycrystalline material, as shown in FIG. 12, the rail surface is worn by repeated start and stop of the disk, and the true contact area with the disk gradually increases. On the other hand, in the example of the present invention, since the rail surface having an appropriate surface roughness does not easily wear, it can be seen that the real contact area with the disk hardly changes even if the disk is repeatedly started.

In the above embodiment, the magnetic head H using the slider having two rail surfaces as shown in FIG. 2 was described, but the same applies to the case where a slider having three or more rail surfaces is used. is there. The magnetic gap is not limited to the one formed by joining the cores 2, and the same applies to a magnetic head in which a magnetic gap is formed by forming a thin film on a slider. Further, the present invention is not limited to the floating magnetic head, and a polycrystal in which the (110) plane similar to that in the above-described embodiment is preferentially oriented in a portion sliding on a magnetic tape or a magnetic disk in another magnetic head. Materials may be used. As shown in FIG. 6, the polycrystalline material according to the present invention has the same wear resistance strength as that of the (110) -oriented single crystal material. It can be used as an alternative to the head.

[0036]

As described above, according to the present invention, in the case where the polycrystalline material is used for the surface facing the magnetic recording medium,
The wear resistance strength can be increased and the surface roughness of the facing surface can be made moderate. Therefore, for example, in the case of a floating magnetic head, it is possible to improve the durability against repeated start and stop of the disk, that is, contact with the disk and floating.

The method of depositing a surface having excellent wear resistance on the surface facing the magnetic recording medium can be carried out by polishing, chemical etching or physical etching.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing a surface state of a rail surface of a floating magnetic head as an embodiment of the present invention,

FIG. 2 is a perspective view showing a floating magnetic head with a surface facing a disk facing upward;

3 is an enlarged partial perspective view showing a magnetic gap portion of the floating magnetic head shown in FIG. 2;

FIG. 4 is an explanatory view of a rail surface of a floating magnetic head observed by an AFM;

FIG. 5 is a plan view of a disk and a magnetic head for explaining an experimental state,

FIG. 6 is a diagram showing the wear resistance test results of the magnetic head of the present invention and a magnetic head having another structure.

7 (A), (B) and (C) are diagrams showing the results of a CSS repeat test using a magnetic head of the present invention manufactured by a polishing operation,

8 (A), (B) and (C) are diagrams showing the results of a CSS repeated test using a magnetic head of the present invention manufactured by reverse sputtering.

9A, 9B and 9C are diagrams showing the results of a CSS repeated test using a conventional magnetic head,

FIG. 10 is a side view showing a state where the floating magnetic head is in contact with the disk;

FIG. 11 is a side view showing a state in which the levitation type magnetic head is levitated from the disk surface;

FIG. 12 is an enlarged cross-sectional view showing a surface of a slider of a floating magnetic head for explaining a conventional problem;

[Explanation of symbols]

 D disk H floating magnetic head G magnetic gap 5 load beam 6 flexure 11 sliders 11a, 11b rail surfaces C1, C2, ... Crystal grains

Claims (4)

[Claims] 1. In a magnetic head having a surface facing a magnetic recording medium made of a polycrystalline magnetic material, a crystal surface having excellent wear resistance of individual crystal grains of the polycrystalline material appears on the facing surface. The magnetic head is characterized by 2. The magnetic head according to claim 1, wherein the magnetic material is a Mn—Zn ferrite-based material, and crystal planes having a mirror index (110) of individual crystal grains appear on the facing surface. 3. The production of a magnetic head according to claim 1, wherein a surface of the polycrystalline material facing the magnetic recording medium is abraded by abrasive grains to deposit a crystal face of each polycrystalline grain having excellent wear resistance. Method. 4. The magnetic material according to claim 1, wherein the surface facing the magnetic recording medium is subjected to chemical etching or physical etching to precipitate a crystal surface having excellent wear resistance of individual crystal grains of the polycrystalline material. Head manufacturing method.