JPS6224848B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a perpendicular magnetization recording/reproducing device. Perpendicular magnetization recording has recently been proposed as a method for improving the recording density of magnetic recording. This magnetizes signals in a direction perpendicular to the surface of the magnetic recording medium, and unlike the generally used method of magnetizing signals in the plane, a high recording density can be obtained. This method of perpendicular magnetization recording is described in the study material of the 1st meeting of the Japanese Society of Applied Magnetics, "An idea for the future of magnetic recording - On the possibility of perpendicular magnetic recording."
(Shunichi Iwasaki, May 26, 1972) describes this in detail, but the outline is as follows. That is, as shown in FIG. 1, the end of the main pole 1 made of a high permeability magnetic film is brought into contact with the magnetic layer 3 of the magnetic tape 2, while the auxiliary pole made of a high permeability magnetic material around which a coil 4 is wound is attached. 5 is placed on the opposite side of the magnetic tape 2, this auxiliary magnetic pole 5 generates a magnetic field, and this magnetic field is applied to the tip of the main magnetic pole 1, that is, the magnetic tape 2.
The magnetic tape magnetic layer 3 is magnetized in the perpendicular direction by concentrating it on the portion in contact with the magnetic tape.

However, the magnetic recording device shown in FIG. 1 has the following problems. That is, when attempting to perform reproduction using this device, the output voltage is so low that reproduction is virtually impossible. Therefore, in this device, a conventional ring-shaped reproducing head must be prepared separately from the conventional ring type reproducing head for reproduction.
This is especially true in places where a multi-track head is used to play back the signal from one track and then record it on another track, since the playback head must be physically separated from the recording head. Time lag is a problem. In addition, because this device uses the main magnetic pole in contact with the magnetic tape, it wears out, and the distance between the main magnetic pole and the auxiliary magnetic pole changes, causing the initially set optimum recording magnetic field to become unobtainable as it is used. go.

Furthermore, the strength of the magnetic field recorded on a magnetic tape varies due to variations in the relative position of the auxiliary pole to the main pole, variations in the shape of the auxiliary pole, variations in magnetic properties, variations in the number of windings, variations in the position of the windings, etc. In order to set a recording signal current value that provides an optimal magnetic field, it is necessary to record on a magnetic tape each time, and then read it back to set the recording signal current value.

This invention has been made in view of the above-mentioned problems, and provides a perpendicular magnetization recording/reproducing device that is capable of reproducing in addition to recording, and is capable of eliminating variations in the recording magnetic field due to wear of the main magnetic pole, etc. The purpose is to

This invention uses a magnetoresistive element, forms a main pole made of a high permeability magnetic film on the side surface of the magnetoresistive element, winds a coil around this main pole, and brings the ends of these films into contact with the tape magnetic layer. The above objective was achieved by arranging the

The present invention will be explained in detail below with reference to the drawings. FIG. 2 shows the basic structure of the present invention. Reference numeral 21 denotes a magnetoresistive element, and one side of the magnetoresistive element 21 has an insulating film 22 sandwiched therebetween, and a main magnetic pole 23 made of a high permeability magnetic film. is formed.
A coil 24 is wound around the main pole 23. The magnetic tape 2 is made to run so that the tape magnetic layer 3 contacts or approaches the ends of these stacked films. The magnetoresistive element 21 is a well-known
It is formed from a Ni-Fe alloy thin film (200 to 1000 Å thick). The insulating film 22 is a non-conductive thin film of SiO ₂ or the like, and is formed by means such as sputtering. The main pole 23 is made of a thin film (approximately 0.5 to 10 μm thick) of a high magnetic permeability alloy such as permalloy.
The insulating film 22 is necessary to prevent the conductive main pole from shooting the magnetoresistive element 21, but it is not necessarily necessary if there is a non-conductive main pole (such as a ferrite film with a very high resistance value). do not have.

Signal recording by this device is performed by passing a signal current through the coil 24 of the main pole 21. That is, by passing a signal current through the coil 24, the main magnetic pole 2
The magnetic film forming the magnetic tape 3 is magnetized, and the magnetic field generated from the tip of the magnetic film records the magnetization of the magnetic tape magnetic layer 3 in the perpendicular direction.

On the other hand, signal reproduction of this device is performed as follows. That is, when the recorded magnetic tape 2 is run, the electrical resistance of the magnetoresistive element 21 changes due to the magnetic field applied from the magnetic tape 2. Therefore, as shown in FIG. 3, a constant DC current I is passed through the magnetoresistive element 21, and the voltage change V across it is detected, and the resistance change of the magnetoresistive element is detected as a voltage change to obtain a reproduction output. . This reproduced signal is sent to amplifier 2
5 and is amplified and extracted.

Note that a bias current magnetic field is often required to improve the nonlinearity of the magnetoresistive element 23 with respect to the magnetic field, but in this case, the main magnetic pole 2
This purpose can be achieved by passing a direct current through the coil 24 of No. 3.

As described above, according to the configuration of the present invention, it has become possible to reproduce signals that were impossible with conventional perpendicular magnetization recording heads. In addition, there is no positional deviation between the recording position and the reproduction position, unlike in the conventional case where a new reproduction head is placed for reproduction. Therefore, this is particularly effective in a track type recording/reproducing apparatus in which information reproduced from one track is recorded on another track because no time lag occurs in the information. Another advantage of this configuration is that the linearizing bias magnetic field of the magnetoresistive element can be generated from the main pole during reproduction.

In addition, problems such as variations in the recording magnetic field due to the position of the auxiliary magnetic pole, problems with the auxiliary magnetic pole due to wear of the main magnetic pole, and changes in the recording magnetic field due to changes in the distance between the main magnetic poles, which are problems with the auxiliary magnetic pole excitation type head shown in Figure 1, can be solved from one side of the magnetic tape. It disappeared because of the record of.

FIG. 4 shows an embodiment of the present invention based on the above-mentioned basic configuration, which is designed to further improve the recording and reproducing efficiency. In this embodiment, the main magnetic pole 4
1 and 42 are provided on both sides of the magnetoresistive element 43, and a high magnetic permeability member 44 is provided on the side surface of the main magnetic pole 41 located on the downstream side of the magnetic tape. According to such a configuration, the first
The magnetic tape 2 is recorded by both the main magnetic pole 41 and the second main magnetic pole 42, but as the tape runs, the main magnetic pole on the downstream side, that is, the magnetic tape runs in the direction of the arrow in FIG. Then, the first main magnetic pole 41
There is no practical problem because the final record is made at In particular, the first main pole 41 has a high magnetic permeability member 44.
The magnetic flux is focused on the first main pole 41 when excited by the coil 45, so a stronger magnetic field is applied to the tip of the first main pole 41 than the second main pole 42. Therefore, only the first main pole 41 actually contributes to recording. Therefore, by providing the high magnetic permeability member 44, recording efficiency is increased. Also, with this structure, the magnetoresistive element 43
It is effective for reproducing short wavelengths because it is shielded and reproduced. In the figure, 46 is a nonmagnetic substrate, and 47 is an insulating film.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional perpendicular magnetization recording device, Fig. 2 is a block diagram of a perpendicular magnetization recording/reproducing device which is the basis of the present invention, and Fig. 3 shows the resistance change of the magnetoresistive element in the configuration of Fig. 2. FIG. 4, which is a diagram illustrating a method for detection, is a diagram showing an embodiment of the present invention. 2... Magnetic tape, 3... Magnetic layer, 21, 43... Magnetoresistive element, 23, 41, 42... Main magnetic pole, 22,
47...Insulating film.

Claims (1)

[Claims] 1. A magnetoresistive element provided to face the magnetic surface of the magnetic recording medium, a main magnetic pole consisting of a high magnetic permeability magnetic film arranged on both sides of the magnetoresistive element, and the magnetic A high magnetic permeability member provided on the side surface of the main magnetic pole disposed on the downstream side in the running direction of the recording medium, a coil wound around the high magnetic permeability member and the main magnetic pole, and a coil wound around the coil during signal recording. means for supplying a desired recording signal current; and means for supplying a bias current to the coil so that the main magnetic pole generates a bias magnetic field for compensating for non-linearity with respect to the magnetic field of the magnetoresistive element during signal reproduction; A perpendicular magnetization recording/reproducing apparatus comprising: means for detecting a change in resistance of the magnetoresistive element.