JPS649644B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the construction of a magnetic head for perpendicular magnetic recording.

The new perpendicular magnetic recording method, which has been attracting attention in recent years as an alternative to the conventional magnetic recording method using a ring-shaped magnetic head, is an order of magnitude faster than the conventional method, mainly because there is no decrease in magnetization due to the self-demagnetizing effect. High recording density can be obtained.

FIG. 1 schematically shows the perpendicular magnetic recording system proposed by Mr. Iwasaki et al.

7 is a main magnetic pole, 2 is an auxiliary magnetic pole, 3 is a recording medium, 4 is a base, and 5 is a high magnetic permeability thin film with an axis of easy magnetization in the horizontal direction, and permalloy is usually used. 6 is a magnetic recording thin film having an axis of easy magnetization in the perpendicular direction, and is made of sputtered cobalt-chromium alloy.

With this configuration, the recording magnetic field is applied in a concentrated manner to the tip of the thin main pole, so that an extremely high recording density can be obtained.

Now, in order to increase the recording capacity per unit area of a recording medium, it is important to increase the recording density not only in the advancing direction of the medium (with respect to the head) but also in the direction perpendicular to it. This is a dimension called the track interval, and is made as short as the output signal amplitude and S/N ratio allow. Usually 100μm, preferably
I want it to be around 30μm.

However, in order to provide tracks with such narrow pitches, the magnetic head must be moved with sufficient precision. It is difficult to mechanically achieve such a mechanism, and it is inevitable that the mechanism will become complicated and the position will change over time. More importantly, moving the entire head increases the mass and inertia of the moving parts, which increases the travel time between tracks and the time it takes to settle into position on the desired track, which increases the amount of information Access time, which is an important factor in storage devices, becomes longer.

The present invention aims to eliminate the above-mentioned drawbacks by minimizing mechanically moving parts.

FIG. 2 is a schematic diagram showing an embodiment of the magnetic head according to the present invention. The recording medium 3 consists of a base 4, a high magnetic permeability thin film 5, and a magnetic recording thin film 6. This medium moves in a direction perpendicular to the plane of the paper. 1 is a main magnetic pole, which is usually in contact with the medium 3. Reference numeral 11 denotes an auxiliary magnetic pole, which is attached to the substrate 12. The substrate is made of non-magnetic material such as glass or ceramics. 14 is a piezoelectric material that expands and contracts in the thickness direction by an electric field. ZnO or Chitavari is suitable as the piezoelectric material, but other materials are also possible. 13 is a common magnetic pole made of high permeability material such as permalloy, and auxiliary magnetic pole 1
1 through a piezoelectric body 14. 18
is a coil for exciting the common electrode 13. Reference numeral 16 denotes an electrode lead connected to each auxiliary magnetic pole, and by applying a voltage between it and the common magnetic pole 13, an electric field is generated in the thickness direction of the piezoelectric body 14.

The functions of this embodiment will be explained below.

As described in detail in the paper by Iwasaki et al., in perpendicular magnetic recording, it is important that the magnetic flux leaving the auxiliary magnetic pole is guided to the main magnetic pole with high magnetic permeability, creating a locally strong magnetic field. It is. In the present invention, the magnetic flux emitted from the common magnetic pole 13 passes through the piezoelectric body 14 to the auxiliary magnetic pole 11, then to the main magnetic pole 1, and then returns to the common magnetic pole 13 via free space. As the thickness of the piezoelectric material (made of non-magnetic material) changes in the middle, the distance between the auxiliary magnetic pole and the common magnetic pole changes, so the number of magnetic fluxes passing through the auxiliary magnetic pole 11 also changes. .

As is well known, in order to leave residual magnetization in a magnetic recording medium, it is necessary to apply a magnetic field greater than the coercive force of the medium. Therefore, if the magnetic field in the medium section is set to be less than the coercive force when the piezoelectric body 14 becomes thicker, and greater than the coercive force when the piezoelectric voltage becomes thinner, any of the four auxiliary magnetic poles can be You can make things recordable. That is, according to this embodiment, by selectively applying a voltage to one of the four piezoelectric bodies, one of the four auxiliary magnetic poles of one excitation coil 18 can be selected as the recordable head. I can do it.

FIG. 2b is a sectional view to help understand FIG. 2a, and the coil, electrode lead, medium, and main pole are omitted for simplicity. (15 is a space and there is nothing there.) Figures 3a, b and c are a plan view a and side views b and c of another embodiment of the present invention. Figure c shows a state in which a voltage is applied to the piezoelectric material 22 and the piezoelectric material 22 is warped.
To simplify the explanation, the main pole, recording medium, and coil are omitted, but please also refer to FIG. 2.

In FIG. 3, the auxiliary magnetic pole 21 is attached to the substrate 12 at a portion 23. The portion 24 is not attached and can be moved away from the substrate 12. 13 is a common magnetic pole. 2
2 is a piezoelectric material having the property of shrinking due to an electric field, and is adhered to the auxiliary magnetic pole 21 in close contact.

Normally, a voltage is applied between the electrode terminals 25 and 26. At this time, the piezoelectric material shrinks, so the auxiliary magnetic pole 21 warps in the direction in which the piezoelectric material is attached, due to the bimetal principle. Therefore, the auxiliary magnetic pole 21
The common magnetic pole 13 is separated. Therefore, the magnetic circuit as a whole is "open" and none of the auxiliary poles will function even if the coil (not shown) is energized. At that time, when the voltage is stopped being applied to only one of the terminals 25, the corresponding auxiliary magnetic pole becomes straight and comes into contact with the common magnetic pole 13.
The magnetic circuit becomes "closed". With this method, one of the four auxiliary magnetic poles can be selected to function as a magnetic pole. According to this configuration, a large change in magnetic resistance can be obtained by creating a gap between the auxiliary magnetic pole and the common magnetic pole by slight deformation of the auxiliary magnetic pole 21, so that the effect is more remarkable than that of the embodiment shown in FIG.

According to this embodiment, the position of the head can be electrically changed over four tracks without using mechanical parts such as a motor. Furthermore, since the time required for selection is very short, access time can be shortened.

In this embodiment, for simplicity of explanation, there are four sets of main magnetic poles and auxiliary magnetic poles, but it is also possible to have more than this. Furthermore, it is also possible to arrange a large number of heads in this embodiment as one unit, or to move this unit every four tracks.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional perpendicular magnetic recording system. 1...Main magnetic pole, 2...Auxiliary magnetic pole, 3...Recording medium, 4...Base, 5...High magnetic permeability thin film, 6...
Thin film for magnetic recording. FIGS. 2a and 2b show an embodiment of the present invention. DESCRIPTION OF SYMBOLS 11...Auxiliary magnetic pole, 12...Substrate, 13...Common magnetic pole, 14...Piezoelectric material Figures 3a, b, and c show other embodiments of the present invention. 27...Plunger.

Claims (1)

[Claims] 1. In a magnetic head consisting of a plurality of auxiliary magnetic poles and a main magnetic pole facing the auxiliary magnetic poles via a magnetic recording medium, the plurality of auxiliary magnetic poles are connected to a common common pole, and the auxiliary magnetic poles and the common magnetic pole are connected to each other. A piezoelectric material is arranged between the auxiliary magnetic poles or on the surface of the auxiliary magnetic poles opposite to the surface facing the common magnetic pole, and the distance between the auxiliary magnetic poles and the common magnetic pole is such that the distance between the auxiliary magnetic poles and the common magnetic poles is changed by deformation of the piezoelectric material to What is claimed is: 1. A perpendicular magnetic recording head characterized by having a structure in which the perpendicular magnetic recording head is independently variable.