JPH0316685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a perpendicular magnetic recording/reproducing head.

A magnetic recording method using a ring-shaped magnetic head currently used in tape recorders and the like performs recording and reproduction using a magnetization vector in the longitudinal direction of the recording medium. If the recording information density is increased and the bit spacing is narrowed by the magnetic recording method using this ring-shaped magnetic head, the strength of magnetization will only decrease due to the demagnetization effect within the magnetic recording medium. Therefore, rotation of the magnetization vector occurs within the cross section of the magnetic recording medium, significantly reducing the reproduction output of recorded information. Therefore, in order to enable high-density magnetic recording, a perpendicular magnetic recording method is required in which the demagnetization effect is close to zero.

This perpendicular magnetic recording method includes the method of Professor Iwasaki of Tohoku University. Figure 1 shows a conventional perpendicular magnetic recording/reproducing head for perpendicular magnetic recording and reproduction of information on a magnetic recording medium used in Professor Iwasaki's method. A main magnetic pole 3 whose periphery is covered with a protective material 2 such as a plastic material, and a coil 4 wound around a high magnetic permeability ferrite material facing the main magnetic pole 3 with the magnetic recording medium A interposed therebetween. Auxiliary magnetic pole 5
It has been established.

In such a conventional perpendicular magnetic recording head, (1)
Since the main magnetic pole 3 and the auxiliary magnetic pole 5 are arranged separately on both sides of the magnetic recording medium A, it is not only difficult to align the main magnetic pole 3 and the auxiliary magnetic pole 5, but also unsuitable for a disk head or a multi-head. It was hot. In addition, (2) the magnetic circuit formed by the main magnetic pole 3 and the auxiliary magnetic pole 5 becomes a closed magnetic path, so the lines of magnetic force spread widely in space, reluctance (magnetic resistance) increases, and energy efficiency deteriorates. Therefore, it is necessary to pass a large current through the coil 4 of the auxiliary magnetic pole 5 during recording, and the magnitude of the output during reproduction is as follows.
Since it depends on the strength of the magnetization vector, which is the signal source of the magnetic recording medium, and is inversely proportional to the reluctance of the magnetic circuit, it has disadvantages such as extremely poor reproduction S/N ratio.

Therefore, the present inventors proposed a perpendicular magnetic recording/reproducing head that eliminates the above-mentioned drawbacks. FIG. 2 is a diagram showing the configuration of the perpendicular magnetic recording/reproducing head. The magnetic recording medium A is made of a material exhibiting strong uniaxial anisotropy in the direction perpendicular to the film surface of the magnetic layer 6.
The material of this magnetic layer 6 is Cr-Co, Gd-
These include RF sputtered films of Co, Gd-Fe, Tb-Fe, and Dy-Fe, and vapor-deposited films of MnBi. Base layer 7
A thin film of a high permeability magnetic material, such as permalloy or Mn-Zn ferrite, is formed by sputtering on a substrate made of glass, ceramic, plastic, etc., or only a permalloy plate, an Mn-Zn ferrite plate, etc. A high permeability plate is used. The main magnetic pole 3 has its tip in contact with the surface of the magnetic layer 6 of the magnetic recording medium A, and has a magnetic axis 1 of a thin strip made of a magnetic material with high magnetic permeability perpendicular to the surface. 1 surrounded by a soft protective material 2. The reason why a soft plastic or the like is used as the material for the protective material 2 is that the tip of the strip 1 is in contact with the magnetic layer and wears out. This is to enable material 2 to be cut.

The magnetic shaft 1 is made of, for example, permalloy, Mn-Zn
Ferrite or the like is used, and its size is set to be several μm in width and 1 μm or less in thickness.

The auxiliary magnetic pole 5 is provided so as to surround the main magnetic pole 3 with a small gap therebetween. That is,
The main magnetic pole 3 is movable within the auxiliary magnetic pole 5. A coil 4 is wound around the auxiliary magnetic pole 5,
The magnetic field is determined by the current flowing through the coil 4 and the number of turns of the coil 4. The yoke auxiliary magnetic pole 8 is provided so that lines of magnetic force form a closed magnetic path from the auxiliary magnetic pole 5 through the magnetic axis 1 of the main magnetic pole 3, the magnetic layer 6 of the magnetic recording medium A, the base layer 7, and the yoke auxiliary magnetic pole 8. There is. The yoke auxiliary magnetic pole 8 is made of a high permeability magnetic material with good frequency characteristics, such as ferrite. The structure is such that a minute gap is created between the yoke auxiliary magnetic pole 8 and the magnetic layer of the magnetic recording medium A during recording and reproduction. This is because when reproducing information, there is a possibility that the output due to magnetic flux detection from the yoke auxiliary magnetic pole 8 will be output from the coil 4, so the magnetic flux of information must be detected from the main magnetic pole 3. It is. In addition, in order to reliably read information from the magnetic recording medium A, a closed magnetic path is configured in the main magnetic pole 3 so that the detected magnetic flux does not leak to the outside.
In order to reduce reluctance (magnetic resistance), the area S of the opposing portion of the yoke auxiliary magnetic pole 8 facing the magnetic recording medium is increased.

To explain the operation of this perpendicular magnetic recording/reproducing head, when recording, a current i corresponding to the information to be recorded flows through the coil 4 wound around the auxiliary magnetic pole 5, which causes the thin magnetic strip 1 of the main magnetic pole 3 to Magnetic flux is concentrated at the tip of the magnetic axis 1 of the magnetic strip, and information is recorded by causing magnetization reversal only in the portion of the magnetic layer 6 of the magnetic recording medium A that is in contact with the tip of the magnetic axis 1 of the magnetic strip. Also, when reproducing recorded information, the magnetic axis 1 of the thin magnetic strip of the main magnetic pole 3 is
The magnetic flux is detected at the tip of the magnetic recording medium A according to the magnetization of the magnetic layer 6, and the coil 4 is
Information is read out and reproduced using the current flowing through it as output.

However, in this proposed perpendicular magnetic recording/reproducing head, since the main magnetic pole 3 is always in contact with the magnetic recording medium A, dust and the like accumulates at the tip of the magnetic axis 1 of the main magnetic pole 3, causing errors during recording and reproduction. There was a drawback that caused this.

SUMMARY OF THE INVENTION An object of the present invention is to provide a perpendicular magnetic recording medium which eliminates the above-mentioned drawbacks and has a means for bringing the main pole into contact with and separating from the magnetic recording medium using air pressure.

The present invention has been made to achieve the above object, and is characterized in that the tip of the magnetic axis is spaced apart from the surface of the magnetic layer of a magnetic recording medium and is arranged perpendicularly to the surface. A magnetic pole, an auxiliary magnetic pole provided to surround the main magnetic pole with a small gap in between, a closed magnetic path from the auxiliary magnetic pole to the magnetic axis of the main magnetic pole, and a magnetic recording medium, and a magnetic recording medium surface. a yoke auxiliary magnetic pole provided to create a minute gap between the yoke and the auxiliary magnetic pole; a coil wound around the auxiliary magnetic pole; The device is characterized in that it includes means for moving the magnetic poles using air pressure.

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 3 is a diagram showing the configuration of an embodiment of the present invention, in which an air feeding unit 9 is disposed at the head of the main magnetic pole 3 shown in FIG. This air feeding unit 9 consists of an air reservoir 11 into which compressed air A ₀ is fed and has a compressed air inlet 10, and an air reservoir 12 that presses the main magnetic pole 3.
A throttle device 13 is provided between the air reservoir 11 and the air reservoir 12 to adjust the pressure.

The perpendicular magnetic recording/reproducing head is located below the magnetic recording medium A, and when not recording or reproducing, it moves downward under the weight of the main magnetic pole 3, and the tip of its main axis touches the magnetic recording medium. It is configured so that it does not come into contact with A.

When recording information with the perpendicular magnetic recording/reproducing head of this embodiment, the air tank valve (not shown) is opened and compressed air Ao is sent into the air reservoir 11 through the compressed air inlet 10. Squeezing device 1
3, the pressure in the air reservoir 12 is adjusted to bring the magnetic axis 1 of the main pole 3 into contact with the magnetic recording medium A at a predetermined pressure.

Next, a current i corresponding to the information to be recorded flows through the coil 4 wound around the auxiliary magnetic pole 5, and as a result, magnetic flux concentrates at the tip of the magnetic axis 1 of the thin magnetic strip of the main magnetic pole 3, and the magnetic strip Magnetization reversal occurs only in the portion of the magnetic layer 6 of the magnetic recording medium A that is in contact with the tip of the magnetic axis 1, and information is recorded. Also, when reproducing recorded information, the main magnetic pole 3
A magnetic flux is detected at the tip of the magnetic axis 1 of the thin magnetic strip according to the magnetization of the magnetic layer 6 of the magnetic recording medium A, and a current flowing through the coil 4 is outputted by magnetoelectric conversion action to read and reproduce information.

FIG. 4 is a diagram showing the configuration of another embodiment of the present invention, in which one side of the yoke auxiliary magnetic pole 8 of the embodiment of FIG. 3 is removed, and only one side of the auxiliary magnetic pole 5 is connected to the magnetic recording medium A through a closed magnetic path. A yoke auxiliary magnetic pole 8' is provided to form a yoke auxiliary magnetic pole 8'. As a result, coil 4
The work of winding the auxiliary magnetic pole 5 around the auxiliary magnetic pole 5 can be made easier.

FIG. 5 is a diagram showing the configuration of an embodiment of the multi-pole head of the present invention, in which a plurality of main magnetic poles 3 are movably arranged in the auxiliary magnetic pole 5 of FIG. be. That is, there is a small gap between the auxiliary magnetic pole 5 and each main magnetic pole 3. Furthermore, a compressed air feeding unit 9 is individually arranged at the head portion of each main pole 3. A coil 4 is wound around the auxiliary magnetic pole 5, and is configured to be capable of recording and reproducing. Originally, each auxiliary magnetic pole would be provided independently and a coil would be wound around each auxiliary magnetic pole, but since it would be a lot of work if multiple auxiliary magnetic poles were used, in this embodiment, the auxiliary magnetic pole 5 is made into one and a coil is wound around each auxiliary magnetic pole. Coil 4 is wound. Therefore, manufacturing of a multi-pole head is simplified. When a current i flows through this coil 4, all of the main magnetic poles 3 are excited, but what is actually recorded on the magnetic recording medium A is the fact that the magnetic axis 1 of the main magnetic pole 3 is connected to the magnetic recording medium A. Only the parts that are in contact. The selection of the contact main poles 3 is carried out by an air supply unit 9 which supplies compressed air to each main pole 3.

The recording and reproducing operations of the embodiments shown in FIGS. 4 and 5 are basically the same as those shown in FIG.
It is omitted here.

It should be noted that the present invention is not limited to the embodiments described above, and it goes without saying that the shape, arrangement, etc. can be changed without changing the gist thereof.

As explained above, according to the present invention, a perpendicular magnetic recording/reproducing head is disposed on one side of a magnetic recording medium by combining a main magnetic pole and an auxiliary magnetic pole, the main magnetic pole and the auxiliary magnetic pole have a special structure, and the magnetic field starts from the main magnetic pole. Since a closed magnetic path is formed in the recording medium, it is possible to improve the efficiency of magnetic energy when recording and reproducing information, and to improve the S/N ratio during reproduction.

In addition, a compressed air supply unit is placed at the head of the main magnetic pole, and compressed air is used to press the main magnetic pole only during recording and playback. This prevents dust from accumulating at the tip of the magnetic axis of the main pole, allowing the magnetic recording medium to It is possible to maintain good contact at all times, and to reduce errors during recording and reproduction.

Note that the same effect as described above can also be achieved by keeping the main magnetic pole and the magnetic recording medium separated, and pressing the magnetic recording medium against the main magnetic pole using air pressure or the like during recording and reproduction. Conceivable. However, in this case, it is inevitable that the traveling magnetic recording medium will be warped, which will shorten the life of the magnetic recording medium. In addition, the magnetic recording medium has a large area relative to the main magnetic pole (tip surface), and by applying a pressing force from the magnetic recording medium side that has this large area, the magnetic recording medium is accurately applied to the tip surface of the main magnetic pole. Bringing them into contact requires a technique that requires precise setting of the positional relationship between the main pole and the magnetic recording medium, as well as the positional relationship between the main pole and the means for forming the pressing force applied to the magnetic recording medium.

In contrast, with this embodiment, it is possible to simply move the main magnetic pole, which has been set and arranged in advance, in its axial direction, regardless of the magnetic recording medium.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a conventional perpendicular magnetic recording/reproducing head, and FIG. 2 is a diagram showing the configuration of a perpendicular magnetic recording head proposed by the present inventors according to the present invention.
FIG. 3 is a diagram showing the configuration of one embodiment of the present invention, FIG. 4 is a diagram showing the configuration of another embodiment of the present invention, and FIG. 5 is a diagram showing the configuration of one embodiment of the multi-pole head of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Magnetic axis, 2... Protective material, 3... Main magnetic pole, 4... Coil, 5... Auxiliary magnetic pole, 6... Magnetic layer, 7... Base layer,
8, 8'... Yoke auxiliary magnetic pole, S... Area of the surface of the yoke auxiliary magnetic pole facing the surface of the magnetic layer of the magnetic recording medium, 9... Compressed air feeding unit, 10... Compressed air feeding port, 11, 12... Air reservoir , 13...
Throttle device, Ao...compressed air, i...current corresponding to information.

Claims (1)

[Claims] 1. A main magnetic pole whose magnetic axis tips are spaced apart and perpendicular to the surface of the magnetic layer of a magnetic recording medium, and an auxiliary magnetic pole that surrounds the main magnetic pole with a small gap in between. A yoke auxiliary magnetic pole is provided to form a closed magnetic path from the auxiliary magnetic pole through the magnetic axis of the main magnetic pole and the magnetic recording medium, and to create a minute gap with the surface of the magnetic recording medium, and a yoke auxiliary magnetic pole is wound around the auxiliary magnetic pole. A perpendicular magnetic recording/reproducing head, comprising: a coil attached to the main magnetic pole; and means for moving the main pole using air pressure so that the tip of the main pole comes into contact with the surface of the magnetic layer of the magnetic recording medium during recording and reproduction. .