JPS62129915A - Vertical magnetic head - Google Patents

Abstract

PURPOSE:To prevent effectively a recording level and recording efficiency from lowering by providing a magnetic material block which has high magnetic permeability at the periphery of a main magnetic pole and then providing pad parts each coated with a thin layer having wear resistance on end surfaces of the block. CONSTITUTION:An auxiliary magnetic pole shield block 19 is arranged opposite a shield block 16 of a magnetic material with high magnetic permeability which surrounds the whole of a main magnetic block 15 across a recording medium 4. A magnetic field 25 is produced by a main magnetic film 11 and an auxiliary magnetic pole 22 and even when an external magnetic field 26 is applied as shown by an arrow X2, it flows in and along the blocks 16 and 19 and exits to the air. Thus, the external magnetic field is shielded evade a decree in recording and reproducing level. Further, the surfaces of pads 17, 18, 20, and 21 provided on the end surfaces of the blocks 16 and 19 are each coated with a protection film having wear resistance, so the wear of the pads and recording medium is reduced to prevent the recording efficiency from decreasing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a perpendicular magnetic head, and more particularly, to a perpendicular magnetic head whose recording/reproducing output level is not affected by an external magnetic field.

[Prior Art] In the perpendicular magnetic recording method in which a magnetic recording medium is magnetized in the direction of its thickness, in principle, the shorter the wavelength (higher frequency) of the magnetization that is magnetically recorded, the more It is known that it is suitable for high-density recording because its self-demagnetizing field is small.

To perform such perpendicular magnetic recording, a magnetic recording medium with large perpendicular magnetic anisotropy and a magnetic recording head that generates a sharp and strong perpendicular component magnetic field are required. As methods for performing perpendicular magnetic recording, there are known an auxiliary pole excitation type perpendicular magnetic head system and a main pole excitation type perpendicular magnetic head system.

In the L auxiliary magnetic pole excitation type perpendicular magnetic head system, as shown in FIG. 2a is a winding 2b for transmitting and receiving information signal current.
The auxiliary magnetic pole 2 around which the auxiliary magnetic pole 2 is wound is placed opposite to the auxiliary magnetic pole 2 with a predetermined gap 3 therebetween. When performing magnetic recording and reproduction, a magnetic recording medium 4 is run through the gap 3, and the magnetized film of the medium 4 is brought into sliding contact with the main pole film 1. The magnetic recording medium 4 is made of Fe on a flexible base 4a made of a polymer film or the like.
A high permeability magnetic layer 4b made of -Ni permalloy or the like is formed, and a perpendicular magnetic recording layer 4C having an axis of easy magnetization perpendicular to the medium surface is further formed thereon.

The operation of the auxiliary pole-excited perpendicular magnetic head configured as described above is such that when an information signal sent from a signal generator (not shown) is applied to the winding 2b, a magnetic field is generated in the auxiliary pole 2, and this magnetic field acts on the main magnetic pole 1 and generates a sharp magnetic field at the tip of the main magnetic pole 1. The information signal is magnetically converted and recorded on the magnetic recording medium 4 by this sharp magnetic field.

In addition, in the above-mentioned auxiliary pole excitation type perpendicular magnetic head system, since the flow of magnetic flux is in an open magnetic path (114 configuration), the above-mentioned sharp magnetic field is caused, for example, from the main pole 1 to the magnetic recording medium 4 to the auxiliary pole. After flowing through a magnetic path 2, it passes through space and returns to the main magnetic pole 1.

By the way, in the open magnetic path configuration as described above, the influence of the external magnetic field due to the motor for driving the magnetic recording medium 4 or the earth's magnetism (1-1 is said to be 0.3 to 0.4 Oerste soto), etc. easy to receive. That is, if this external magnetic field is applied perpendicularly to the bipedal magnetic recording medium 4 as indicated by the thick arrow X shown in FIG. The magnetic field passing through the magnetic recording medium 4 and the auxiliary magnetic pole 2 is as shown by the thin arrow. Therefore, if a strong external magnetic field such as ``double'' is applied when magnetic recording of - information signals is completed and this magnetic recording is being generated, the reproduction signal may change depending on the magnitude of this external magnetic field. The playback output level may be reduced.

When such a phenomenon is actually realized A111, it becomes as shown in FIG. That is, in the auxiliary pole excitation type perpendicular magnetic head system shown in FIG. 3, a perpendicular external magnetic field having a strength of 11I type is applied to the magnetic recording medium 4. Then, if the reproduction output level when no external magnetic field is applied is taken as "1" on the vertical axis, and the applied external magnetic field (medium level: Oe (Oersted)) is taken on the horizontal axis, as shown in Figure 4 above. When the external magnetic field becomes 1 oersted, the reproduction output level becomes almost zero.

The effects of external magnetic fields not only reduce the recording/reproducing output as described above, but also reduce the recording level, or when the magnetic head comes close to or comes into sliding contact with a medium that has already been recorded while no recording/reproducing operation is being performed. This appears as a reducing effect on the residual magnetization of the medium. The reason why such an effect of an external magnetic field appears is considered to be due to the following principle.

Figure 5 is a diagram showing the B-H characteristics of the main pole of a perpendicular magnetic head, and Figure 6 is a diagram showing the B-H characteristics of a recording medium magnetized by a perpendicular magnetic head that operates with the characteristics shown in Figure 5. It is a diagram. In the absence of an external magnetic field, the main pole is magnetized in the positive and negative directions around the origin O to a magnetic flux density of approximately the saturation level ±Bs, as shown in FIG. 5, in response to the alternating magnetic field generated by the recording signal. On the other hand, the S3 plot is magnetized in the positive and negative directions up to the saturation level magnetic flux density as shown in Figure 6 by the magnetic field generated by the main magnetic pole that is magnetized in a series.
The residual magnetic flux ±Br is maintained. This state is a state in which normal magnetic recording is performed on the recording medium. When an external magnetic field (for example, a positive direct current magnetic field due to the earth's magnetism or a DC motor magnet) is applied, the magnetizing force (magnetic field) acting on the main pole is
This external magnetic field acts harmonically (that is, the magnetizing force shifts in the positive direction on the horizontal axis in FIG. 5).

As a result, the operating center of the magnetization (magnetic flux density) of the main pole moves to point A in Figure 5, so even if it is magnetized to the saturation level Bs in the positive direction, the saturation level -B in the negative direction.
It may happen that it is not magnetized up to s. In this way, when a recording medium is magnetized by a magnetic field emitted from a main pole with a biased magnetization state, residual (
For the Ia flux, the above-mentioned +Br is maintained in the positive direction, or -Bk is smaller in absolute value in the negative direction (see Figure 6).
only will be retained. In other words, the external magnetic field causes a decrease in the magnetic recording level.

Next, a state in which the reassembled magnetic head is in close proximity to or in sliding contact with a recording medium whose magnetization state is biased, as in the case of the third
In the state shown in the figure), when an external magnetic field is applied to the extent that the magnetization of the main pole reaches point A in Figure 5, the magnetizing force of this external magnetic field (the magnetic field mainly focused on the main pole) causes the recording medium to The magnetization state at is the initial residual magnetization -B
k to the value corresponding to point A' in FIG.

After this change, even if the external magnetic field is removed and the magnetizing force by the main pole disappears, the magnetization state of the recording medium does not return to the original residual magnetization -Bk, but has a smaller absolute value -Bk.
' (see Figure 6). This is because, as is well known, the relationship between changes in the magnetic field (magnetizing force) and the corresponding magnetization (magnetic flux squash) is irreversible.

As mentioned above, when an external magnetic field is applied to a recorded magnetic recording medium, or when the applied state is subsequently removed, the residual magnetization (i.e., the magnetic recording level) will be reduced. . Needless to say, this tendency is particularly noticeable when the main pole of the four-direct magnetic head is close to or in sliding contact with the recording medium.

Next, let us consider four cases in which an external magnetic field (the same DC magnetic field as described above) is applied when reproducing recorded information from a medium on which IF normal magnetic recording has been performed as described above. In this case, since the external magnetic field acts harmonically on the magnetic field emitted from the already recorded medium, the operating point at the main pole of the perpendicular magnetic head is more positive than the origin 0 on the horizontal axis in FIG. direction, and moves to point A1 or, if the external magnetic field is particularly strong, to point B. B- in Figure 5
As is clear from the H characteristic, when operating around point A or point B, the magnetization (magnetic flux in the main pole The skinning rate (density) is significantly reduced and becomes almost zero in the positive direction from point B. Therefore, the reproduction sensitivity decreases.

In this way, the recording/reproducing level decreases due to the influence of external magnetic fields, and the recording level of the medium that is already recorded when the magnetic head comes close to or comes into sliding contact with the medium.
This phenomenon is observed not only in the auxiliary pole excitation type perpendicular magnetic head system described above, but also in the main pole excitation type perpendicular magnetic head system described above. In other words, it is known that in the perpendicular magnetic recording method, the influence of external magnetic fields is greater than in the conventional longitudinal recording method.

By the way, in general, there is a technique for installing a shield to prevent electromagnetic induction interference (for example, it is also described in "Electronic Circuit Noise & Trouble Countermeasures" written by Mitsuru Nariki and published by JCQ Publishing).
, or the technology of providing a shield to prevent electrostatic noise (see Japanese Unexamined Patent Application Publication No. 186112/1982) is already well known, or is it a technology unique to JP direct magnetic recording as described above? It has not yet been established as a technology to solve the problem.

Therefore, the present applicant first surrounded the main pole of the reassembled magnetic head with a high magnetic permeability magnetic part to provide a magnetic shield, so that even if an external 1a field was applied, recording and recording due to the influence of the external magnetic field. We have proposed a perpendicular magnetic head that prevents a decrease in the reproduction level and also prevents a decrease in the recording level on a recorded recording medium when the magnetic head comes close to or in sliding contact with the medium (Japanese Patent Application No. 1983- No. 255458).

In addition, 1 [In direct magnetic heads, in order to improve recording efficiency, it is necessary to reduce separation loss caused by the presence of a gap between the 1nll'E magnetic recording medium and the +: magnetic pole; It is necessary to completely shield the main pole and the magnetic recording medium so that the separation distance approaches zero.

On the other hand, it is necessary to maintain the distance between the magnetic poles between the tip of the main magnetic pole and the tip of the auxiliary magnetic pole to a certain constant value.

For this reason, a bat made of a material that exhibits lubricity is generally used, but the sliding contact with the magnetic recording medium causes severe wear, making it difficult to maintain a constant distance between the magnetic poles, and making it difficult to maintain the distance between the magnetic poles. It also causes damage such as scratches.In addition, in Japanese Patent Application Laid-Open No. 57-138018, a roller is attached to the tip of the auxiliary magnetic pole to press the magnetic recording medium to the main magnetic pole. The roller is provided so that it can rotate as it travels, and the outer surface of this roller is made uniform with a cross section perpendicular to its rotational axis or a magnetic core made of a circular magnetic material centered on the rotational axis. The pad is made of a non-magnetic material or a low-permeability magnetic material that is covered with a uniform thickness, but such a pad is minute and requires a complicated structure, and is expensive to manufacture. I end up.

[Problems to be solved by the invention] This invention is based on the patent application filed in
The purpose is to further reform No. 5458, so that even when an external magnetic field is applied, the recording/reproducing output level and the recording level of the medium when the magnetic head is close to or in sliding contact with the medium are not affected. To provide a perpendicular magnetic head which is magnetically shielded and whose magnetic recording efficiency does not deteriorate due to abrasion of non-magnetic pads in sliding contact with a recording medium.

[Means and Works for Solving the Problems] The present invention provides magnetic shielding by surrounding the main pole of a perpendicular magnetic head with a high magnetic permeability magnetic member, and
A non-magnetic pad disposed on this perpendicular magnetic head is coated with a wear-resistant abrasive-free material, and the recording medium is guided to the proper position of the perpendicular magnetic head, causing wear and tear on the pad portion and the magnetic recording medium. This greatly reduces damage and improves recording efficiency.

[Examples] The present invention will be described below based on illustrated examples. 1st
Figures (A), (B), and (C) show a first embodiment of the present invention, which is applied to an auxiliary pole excitation type perpendicular magnetic head. In addition, also in the present invention,
As the magnetic recording medium 4, it is desirable to use one exactly the same as that shown in FIG. That is, as described above, the magnetic recording medium 4 has a high permeability magnetic JiZ4b made of Fe-Ni permalloy m° formed on a base 4a made of a polymer film or the like, and A perpendicular magnetic recording layer 4C having an axis of easy magnetization in a direction perpendicular to the medium surface is formed on the surface of the medium.

As shown in Figure 1 (A), (B), and (C),
The auxiliary pole excitation type perpendicular magnetic head 50 includes a main pole block 15, a main pole shield block 16, an auxiliary pole shield block 19. It is configured to include an auxiliary magnetic pole 22 and the like.

The main pole block 15 has a main pole film 11 made of an amorphous magnetic metal such as cobalt zircon niobium, cobalt zircon molybdenum, permalloy, sendust, etc., and the left and right sides (in FIG. 1A) of the main pole film 11 are made of crystallized glass, These main pole films 1 are sandwiched by main pole sandwiching members 12 and 13 made of non-magnetic ferrite, etc.
1. The lower surface of a magnetic block 14 made of a high magnetic permeability magnetic material such as manganese zinc ferrite or nickel zinc ferrite is bonded to the -1 part of the holding members 12 and 13. The lower surface of the main magnetic pole block 15 is polished into an arc shape, and the lower end surface of the main magnetic pole film 11 is exposed.

A box-lid-shaped main pole rolled block 16 made of the same material as the magnetic block 14 and open at the bottom is disposed so as to entirely surround the main pole block 15. The gap between the main magnetic pole shield block 16 and the main magnetic pole block 15 is filled with epoxy resin, water glass, or the like. The above main magnetic pole unruled block: Soku 1
A semi-cylindrical pad 17 made of a lubricating material such as glass-like carbon is located near the outer end of the left and right lower end surfaces of 6.
．． 18 are joined. And this pad 17.1
8 and the lower end surfaces of the main pole film 11 are arranged so that they are on the same plane.

The hli auxiliary magnetic pole shield block has a thick plate shape made of the same material as the magnetic block 14, and has a width that is 2/3 of the main magnetic pole shield block 16.
An auxiliary magnetic pole 22 made of a columnar ferrite or the like of >ifQ is disposed at the center of the upper surface of the magnetic block 23, at a position facing the lower end surface of the main magnetic pole film 11.
are joined, and a winding 24 for signal transmission and reception is wound around the outer periphery of this auxiliary magnetic pole 22. Further, on the left and right ends of the two sides of the magnetic block 23, there are pads 17 and 18 marked with "-".
A semi-cylindrical band 20° and 21 made of the same material as 20° and 21 is joined.

The surfaces of the L pads 17, 18, 20 and 21 are covered with protective films 17A and 18A made of a wear-resistant inorganic material.

Cover each of 2OA and 21A to a thickness of about 1 μm. This inorganic material is, for example, SiC.

SiOSiN, TiN, Ag2O3 and 2″ TiC etc. are suitable.

Then, the auxiliary magnetic pole shield block 19
A surface having the a-pole 22, the main pole film 11 of the main pole block 15, and the main pole shield block 16.
and the lower surface thereof are arranged to face each other with an appropriate gap.

This air gap is extremely narrow, making it difficult for external magnetic fields to enter. Further, the magnetic recording medium 4 is pushed between the above-mentioned air gap by the pads 17.18 and 20.21 on both sides, and runs in the direction of the arrow X1 while slidingly contacting the main pole film 11. .

When magnetic recording is performed using the auxiliary magnetic pole excitation type joint magnetic head 50 configured as shown in FIG.
), the auxiliary magnetic pole 22 and the +:magnetic)iII film 11
The magnetic field generated by this looks like two thin ellipses lined up on the left and right, as shown by reference numeral 25. Furthermore, even if a perpendicular external magnetic field (indicated by arrow The light is divided into left and right parts and proceeds downward, passes through the magnetic recording medium 4, reaches the magnetic block 23, and is further dissipated into the air from the bottom surface of the magnetic block 23. In other words, the inner magnetic field shown in No. 71 No. 25 above,
It is completely separated from the outer magnetic field shown in No. 71 No. 26, and the outer magnetic field (external magnetic field) does not affect the inner magnetic field (recording magnetic field). Therefore, a decrease in the recording/reproducing level caused by an external magnetic field and a decrease in the recording level of the medium when the magnetic head comes close to or comes into sliding contact with the medium at the recorded edge can be effectively avoided.

If the pads 17, 18, 20, and 21 have soft magnetism, the shielding effect can be further improved by -1. In addition, the pads 17, 18, 20 and 21 have protective films 17A, 18A, 2O made of an abrasive inorganic material (H).
Since A and 21A are each reversed, each pad slides into contact with the magnetic recording medium 4 with reduced friction, and the perpendicular magnetic head 50 is always guided to the proper position, preventing wear and tear on the pad portion and the magnetic recording medium. (R scratches are significantly reduced and recording efficiency is not reduced.

Next, the second embodiment of the present invention is shown in FIGS. 2(A) and 2(B).
).

The explanation will be based on (C). This embodiment is a case where the present invention is applied to a main pole excitation type perpendicular magnetic head. In the embodiment described below, constituent parts that are completely similar to those already described in the first embodiment are given the same reference numerals, and their explanations will be omitted.

As shown in FIGS. 2(A), (13), and (C), the main pole excitation type perpendicular magnetic head 100 includes a main pole block 31, a main pole shield block 16, a pad mounting block 32, etc. has been done.

The main pole block 31 is composed of a magnetic block 33, a main pole film 11, main pole holding members 12A, 13A, and the like. That is, the lower surface center (second
In Figure (A), four parts are formed, and a winding 24A is wound around a protrusion formed approximately in the center of the recessed part on the lower surface. The main magnetic pole 11 is attached to the protrusion.
One end surface is joined, and the left and right side surfaces of this main pole film 11 are held between main pole holding members 12A and 13A, and this sandwich 1
The upper end surfaces of the j members 12A and 13A are joined to the lower surface of the magnetic block 33.

A main magnetic pole shield block 16 is disposed so as to surround the fertilized magnetic pole block 31, and pads 17.
18 are joined.

Further, a pad mounting block 32 is provided below the main pole block 31. This pad mounting block 32 is a rectangular plate made of the same material as the magnetic block 14 (see FIG. 1, 2), and has a strip attached to the magnetic block 33 in its center. (A corresponding convex portion 32a is also provided.Furthermore, bats 20 and 21 each having a cylindrical shape are joined near both left and right ends of the second surface of the bat mounting block 32.

Then, the entire lower surface including the lower end surface of the main magnetic pole block 31 and the main magnetic pole shield block 16 and the convex portion 32a of the pad mounting block 32 are opposed to each other across a predetermined gap such as 1=I+i. It is located. Between this gap, the magnetic recording medium 4 is recorded on both sides of the pad 17.
．． 18 and 20.21, and travels while slidingly contacting the -1- soil magnetic pole film 11. In addition, on the surface of each of bats 17, 18, 20 and 21 mentioned above, there are protective films 17A, 18A, 2OA and 2LA made of wear-resistant inorganic material, respectively, as in the first embodiment. Covered. By providing the convex portion 32a, the magnetic resistance can be reduced and the efficiency of the main pole excitation type perpendicular magnetic head can be improved.

When performing magnetic recording and +Tj generation using the main pole excitation type perpendicular magnetic head 100 constructed in 1.1.7 as described above, the arrow Y as shown in FIG. Even if an external magnetic field is applied from the direction . 1 No. 3
The pads 17, 18, 20, and 21 are completely isolated from the external magnetic field shown in 4, effectively avoiding the above-mentioned problems caused by the external magnetic field, and each pad 17, 18, 20, and 21 has a +ljJ abrasion resistance.
Pouch membranes 17A, 18A.

By 2OA and 21A? fE, the magnetic recording medium 4 slides into contact with reduced friction, and the perpendicular magnetic head 100 is always guided at Jli+IE (+'), which greatly reduces wear of the band portion and magnetic recording medium and jM (u). to improve recording efficiency.

[Effects of the invention] As mentioned above, the direct magnetic head F of this invention is (111%
This avoids a decrease in the recording/+lil reciprocity caused by an external magnetic field and a decrease in the recording level on the medium when the surface magnetic head slides into contact with the recording medium, and also prevents the recording medium from being exposed to the pad portion. It is guided to the proper position by the
is significantly reduced.

[Brief explanation of drawings]

FIGS. 1(A), (B), (C), and (D) are a sectional view of a 1lli auxiliary pole excitation type vertical advance head showing an embodiment of the present invention, and an exploded perspective view of the main parts, 2 (A), (B), (C), (+)) showing the paths of the external magnetic field and the recording/reproducing magnetic field are main pole excitation type diagrams showing other embodiments of the present invention. A cross-sectional view of a perpendicular magnetic head, a perspective view of the main parts disassembled, and a line diagram showing the paths of the external magnetic field and the recording/reproducing magnetic field. (A side view showing the b configuration. Figure 4 shows the conventional auxiliary magnetic pole excitation +a bar shown in Figure 3.) Fluctuations in the reproduction output level of the +1 raw signal when an external magnetic field is applied to the vertical magnetic head. Figure 5 is a diagram showing the B-H characteristics of the main pole of a perpendicular magnetic head, and Figure 6 is a diagram showing the B-H characteristics of the main pole of a perpendicular magnetic head. It is a diagram showing the B-H characteristics of the recording medium. 4.
Recording medium 11・・・・・・・・・・・・・・・・・・
・・Juuken, Pole 14.33・・・・・・・High magnetic permeability block 17.18.20.21 ・・・・・・
... Butt part 50.100 ... Vertical magnetic head 'AF-)l Diagram 2 (B) (C) (
Ørsted J

Claims (1)

[Claims] In a perpendicular magnetic head that is provided in close proximity or in sliding contact with a perpendicular magnetic recording medium, a block of high magnetic permeability magnetic material provided around the main pole and in sliding contact with the perpendicular magnetic recording medium are provided. In order to regulate the position of the medium with respect to the perpendicular magnetic head within a predetermined range suitable for recording and reproducing, it is provided on the high magnetic permeability magnetic material block, and at least the sliding contact surface with the medium has an anti-friction and resistant material. A perpendicular magnetic head comprising: a pad portion formed with an abrasive thin layer;