JPH0447366B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a single-pole magnetic head for recording and reproducing data on and from a perpendicular recording medium having perpendicular magnetic anisotropy.

[Prior Art] Magnetic recording is a method in which a signal magnetic field is applied to a moving magnetic recording medium by a magnetic head, and residual magnetization corresponding to the signal is recorded in the direction of movement of the medium, and a large amount of information can be recorded at low cost. Since then, it has been widely used in fields such as recording, computer information storage, and measurement.

In recent years, perpendicular magnetic recording systems that use cobalt-chromium alloy thin films with perpendicular magnetic anisotropy as recording media are suitable for high-density recording because their recording densities have increased dramatically compared to conventional recording systems. This recording method is seen as promising, and efforts are being made to put this recording method into practical use.

FIG. 1 shows a conventional single-pole head of the main pole/auxiliary pole type that exhibits the best performance as a perpendicular magnetic recording head used in the perpendicular magnetic recording system.

In FIG. 1, 1 is a main pole made of a magnetic thin film with high permeability such as permalloy, 2 is a magnetic ferrite, 3 is a coil, and 4 is a recording medium.

The main magnetic pole 1 is in contact with the recording medium 4, and the main magnetic pole 1
An auxiliary magnetic pole consisting of a ferrite 2 and a coil 3 wound around the tip of the ferrite 2 is disposed opposite the main magnetic pole 1 on the opposite side of the recording medium 4.

In such a magnetic head, recording is performed by the coil 3.
The main magnetic pole 1 is excited, and the portion of the recording medium 4 that is in contact with the main magnetic pole 1 is magnetized.

Playback (reading) is performed on the recorded recording medium 4.
The main magnetic pole 1 is magnetized by the magnetic field emitted from the main pole 1, and the residual magnetization is detected by the coil 3.

The above type of magnetic head has excellent performance, but since the magnetic head is arranged separately on both sides of the recording medium, it is difficult to put it into practical use due to the high cost and the position of the main magnetic pole and auxiliary magnetic pole. Since it is not easy to adjust the fit, it is difficult to put it into practical use.

Further, as a magnetic head, there is a ring type magnetic head. This is because a magnetic material with high magnetic permeability forms a closed circuit, a coil is wound around this magnetic material, and an air gap is formed in a part of the closed circuit to break the magnetic circuit. There is.

Recording is performed by magnetic flux leaking from this air gap, and the magnetic flux leaking from the recording medium is drawn into the magnetic material through this air gap and reproduced by a coil.

Therefore, the ring-type magnetic head is characterized by high recording and reproducing efficiency.

However, as is clear from the principles of recording and reproduction, as the recording density on the recording medium increases,
It became necessary to reduce the width of the gap. That is,
The gap width must be smaller than the magnetic recording wavelength.
A sufficient reproduction signal cannot be secured.

Furthermore, if the thickness of the recording magnetic layer is made thinner, the leakage magnetic flux becomes smaller, and thus the reproduction output of the ring-shaped magnetic head is reduced. On the other hand, perpendicular magnetic recording media are materials that allow high-density magnetic recording even if the thickness of the recording magnetic layer is increased, and in combination with a magnetic head capable of high-density recording, a magnetic recording system with high density and high reproduction output can be created. will be realized.

The ring-type magnetic head has the above-mentioned drawbacks and an additional drawback that the component of the magnetic field generated during recording in the direction of the thickness of the recording medium is small, so that it cannot be used for perpendicular magnetic recording.

Furthermore, considering a perpendicular recording system that combines a perpendicular magnetic head with a disk-shaped flexible perpendicular recording medium, there is a need for a magnetic pole head with a structure that guarantees data read compatibility even when off-track occurs. .

FIG. 2 is an explanatory diagram of the layout of a gap portion of a conventional floppy head for in-plane recording.

The conventional longitudinal recording method shown in FIG. 2 has a structure in which, in addition to the magnetic head 5 for recording and reproducing as shown in FIG. 2, erase heads 6 and 7 are provided to prevent interference with adjacent tracks. . Note that 8 is a recording/reproducing gap, and 9 and 10 are erase gaps.

The operation of the magnetic head shown in FIG. 2 will be explained below.

With the recording/reproducing gap 8 and erase gaps 9, 10 in contact with the magnetic recording medium, the magnetic recording medium moves in the direction shown by the arrow in FIG. 2 (the running direction of the medium).

At this time, a magnetic field corresponding to the data signal is generated in the recording/reproducing gap 8, and data is recorded on the magnetic recording medium in a band shape having the width of the recording/reproducing gap.

Even if some recording has been made on the magnetic recording medium before this recording, the previous recording is not erased.

Therefore, there is a possibility that various undesirable magnetic recordings remain on both sides of the newly recorded recording/reproducing gap width band.

This undesirable recording may be previously written data or may be data from adjacent tracks due to positioning errors as the head moves from track to track.

The data on both sides of this recording band acts as noise due to the positional deviation that naturally occurs when the head is moved to another track and then returned to this track, making it easy to read data errors.

To prevent this, a constant magnetic field sufficient to erase the recorded contents on the magnetic recording medium is generated at the erase gaps 9 and 10 of the erase head at the same time as recording, and a constant width on both sides of the magnetically recorded band, that is, the erase gap width is generated. Only the data will be deleted.

The magnetic heads in FIG. 2 are recording/reproducing heads 5,
It has a structure that combines three head parts, erase heads 6 and 7, and has a structure that makes it difficult to reduce manufacturing costs.

Furthermore, for high recording densities, especially high track densities, each component becomes thinner and smaller, making it extremely difficult to manufacture the components.

If the recording/reproducing head and the erase head are placed too close together, interference will occur between the heads, so they must be separated by a predetermined distance.

The perpendicular recording head system must also have a structure that has the same functions as the magnetic head shown in Figure 2 above, but a magnetic head with main magnetic poles and auxiliary magnetic poles for recording and reproduction, and main magnetic poles and auxiliary magnetic poles for erasing is Since each magnetic head has an open magnetic path structure, mutual interference occurs and the magnetic heads do not function properly.

From this point of view as well, a new magnetic head structure is desired.

[Problems to be Solved by the Invention] As described above, conventional magnetic heads have various problems for perpendicular magnetic recording and are not practical.

The object of the present invention is to provide a magnetic head which is practical and has high performance as a magnetic head for perpendicular magnetic recording in order to solve the above-mentioned problems.

[Means for Solving the Problems] The present invention provides a single-pole type magnetic head for recording and reproducing information on a perpendicular recording medium having perpendicular magnetic anisotropy, which includes a main pole consisting of a plurality of spaced apart high-permeability thin films. is in contact with a recording medium, and a coil wound around the main magnetic pole is disposed only on one side of the recording medium, and the main magnetic pole and the coil record at a predetermined width. This magnetic head is characterized in that reproduction is performed by a coil formed by a magnetic pole that is a part of the main magnetic pole having a smaller magnetic pole width and a thin film wound around the tip of the magnetic pole.

[Function] The magnetic head of the present invention configured as described above is of the type in which the magnetic circuit is open, as shown in FIG. 3 of the embodiment described later, which is used for perpendicular magnetic recording. It is a single-pole type vertical magnetic head located only on one side.

Therefore, in a type of magnetic head with an open magnetic circuit, the magnetic resistance of the magnetic circuit itself is extremely large, so it is not possible to control the gap width etc. as with conventional ring-shaped magnetic heads. Have difficulty.

To this end, in the present invention, as described above, windings for recording and reproduction are provided separately.

With this configuration, a magnetic head that can generate a strong magnetic field necessary for recording and has high reproduction sensitivity has become possible.

When current is passed through the recording coil wound around the main magnetic pole, the magnetic head of the present invention has an open magnetic circuit, so the generated magnetic field spreads out into space without being concentrated, reaching the tip of the main magnetic pole. .

The reached magnetic field is concentrated on the main magnetic pole portion, and as a result, a strong perpendicular magnetic field is generated, making it possible to perform good perpendicular magnetic recording.

Also, during playback, the main pole can efficiently collect the magnetic field leaking from the surface of the magnetic recording medium.
Since the magnetic circuit is open, the magnetic field concentrated at the tip of the main magnetic pole immediately leaves the magnetic pole and does not reach the recording coil.

However, if a thin film is used to form a coil at the tip of the main pole, it will be wound very densely at the tip.
Sufficient magnetic flux passes through the thin film reproduction coil, and even with an open magnetic circuit, sufficient reproduction output can be obtained.

Furthermore, the magnetic field from the main pole on which the reproducing coil is not wound is almost not detected by the reproducing coil because it immediately exits the magnetic pole and spreads as described above.

In this way, by providing the recording coil and the reproducing coil separately, each can be designed optimally, and it is possible to flow sufficient current to the recording coil, and it is possible to flow a sufficient current to the reproducing coil. By being formed at an extremely high density at the tip of the main magnetic pole, high sensitivity and high reproduction output can be obtained, and there is no stroke between adjacent tracks.

Next, embodiments of the present invention will be described.

[Example] FIG. 3 is a cross-sectional explanatory diagram of a magnetic head which is an embodiment of the present invention, and FIG.
It is an explanatory view of A' cross section.

In the figure, 11 is a non-magnetic substrate, 12, 13,
14 is a high magnetic permeability thin film, 15 is a thin film coil (for reproduction), 16 is a coil (for recording), 17 and 18 are conductive films forming the thin film coil 15, 19 is a dielectric protective film, and 20 and 21 are an insulating film, 22 a protective film, 23 ferrite, 24 a perpendicular magnetic recording layer,
25 is a recording medium base material, 24 and 25 form the recording medium 4, and 27 indicates the moving direction of the recording medium.

The magnetic head of the present invention has a pattern formed by photoetching a thin film.

A high magnetic permeability thin film 12 such as permalloy is formed on a nonmagnetic substrate 11 made of a single crystal or polycrystalline material such as nonmagnetic ferrite, alumina, spinel, silicon, or a glass material such as quartz glass or borosilicate glass.
13 and 14 are patterned to form a high magnetic permeability thin film 1.
A reproducing thin film coil 15 is wound around the tip of 2.

Furthermore, a recording coil 16 is wound around the high magnetic permeability thin films 12, 13, and 14 at the rear of the high magnetic permeability thin film 12.

Next, referring to FIG. 4, an example of the structure of the magnetic head of the present invention will be described with reference to an example of use in a head/recording medium contact type disk type memory such as a floppy disk drive memory device.

As shown in FIG. 4, the magnetic head has a dielectric protective film 19 formed on a non-magnetic substrate 11, and a conductive film 17 which is a part of a reproduction thin film coil 15 on top of the dielectric protective film 19.
is formed by patterning. Next, insulating film 2
0 is formed and a high magnetic permeability thin film 12 is patterned thereon, and high magnetic permeability thin films 13 and 14 are also formed at the same time as patterning. By doing so, no process is added to form the high magnetic permeability thin films 13 and 14.

Next, an insulating film 21 is placed on the high magnetic permeability thin film 12, and a conductive film 1, which is a part of the thin film coil 15, is further placed on top of the insulating film 21.
8. A protective film 22 is further formed to protect the entire structure.

Further, as shown in FIG. 4, a recording coil 16 and a reproducing coil 15 are arranged only on one side of the recording medium 4, which is formed by providing a perpendicular magnetic recording layer 24 on a recording medium base material 25. This is a feature of the magnetic head of the present invention.

Further, a ferrite block 23 is provided inside the recording coil 16 in order to improve recording efficiency.

Next, the operation of the magnetic head of the present invention will be described.

First, recording is performed by passing a current through the coil (for recording) 16 to simultaneously excite all the high magnetic permeability thin films 12, 13, and 14.

In that case, the recording width is the high magnetic permeability thin film 12, 13,
14, so if the respective recording track widths are T12, T13, and T14, the entire recording width is T12.
+T13+T14.

To explain this with reference to FIG. 3, the width of the high magnetic permeability thin film 13 in FIG. This is the width shown in .

Therefore, the entire recording width is the width from the left side of hatch 13 to the right side of hatch 14 in the figure.

At this time, the high magnetic permeability thin film 12 and the high magnetic permeability thin film 1
3. The gap between the high magnetic permeability thin film 12 and the high magnetic permeability thin film 14 is set to the extent of blurring the recording width during recording,
Consideration should be given so that the entire width of T12 + T13 + T14 can be recorded uniformly.

Since there is very little bleeding in recording on the perpendicularly magnetized film by the main pole 1, the gap must be within several μm.

Next, reproduction is performed by detecting changes in magnetic flux passing through the high magnetic permeability thin film 12 using the thin film coil 15. The reproduction track width in this case is T12.

Since it is easy to form the thin film coil 15 at the very tip of the high magnetic permeability thin film 12 by using microfabrication technology using photoetching technology, a large magnetic flux passing through the tip of the high magnetic permeability thin film 12 can be detected.

Therefore, it is possible to obtain reproduction comparable to that of conventional magnetic heads of the main magnetic pole/auxiliary magnetic pole type.

In order to avoid the influence of magnetic flux passing through the high magnetic permeability thin films 13 and 14 during reproduction, the high magnetic permeability thin film 12 and thin film coil 15 are sufficiently separated from the high magnetic permeability thin films 13 and 14 at a position away from the tip of the magnetic head. It is arranged like this.

With the high magnetic permeability thin film 13 and the high magnetic permeability thin film 14,
Data compatibility can be guaranteed even if there is off-track.

If the amount of off-track is x, if T13 and T14 are set so that T13<2x, T14<2x, even if off-track occurs, the high permeability thin film 12 will be magnetized within the width of T12+T13+T14. Therefore, it is not affected by recording signals of adjacent tracks.

Furthermore, in this case, the playback output does not decrease even when off-track.

Furthermore, manufacturing costs can be reduced because the thin film portion is manufactured by creating a large number of head patterns on a large substrate and cutting them out to make each magnetic head one by one.

[Effects of the Invention] As described above, the magnetic head of the present invention has been described. To summarize the characteristics of the present invention again, it is a monopolar perpendicular magnetic head located only on one side of the recording medium, and the reproduction efficiency is low. Although the head is expensive and has a structure that guarantees data compatibility during off-track, the number of steps in the manufacturing process is not increased at all, so it can be manufactured at low cost.

The fact that conventional erase head parts are not required also helps in reducing costs.

Another advantage of this magnetic head is that since all the cores are formed on the same plane, it can be easily adapted to higher track densities and smaller recording medium sizes.

Therefore, the magnetic head according to the present invention is excellent in both structure and manufacture, is practical, and will greatly contribute to the practical application of perpendicular magnetic recording systems.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional main pole/auxiliary magnetic pole type perpendicular magnetic head, Fig. 2 is a schematic diagram of the gap section layout of a current floppy head for longitudinal recording, and Fig. 3 is an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view taken along line A-A' in FIG. 3. 1... High magnetic permeability thin film (main magnetic pole), 2... Ferrite, 3... Coil, 4... Recording medium, 5... Recording/reproduction head, 6, 7... Erase head, 8
... Recording/reproducing gap, 9, 10... Erase gap, 12, 13, 14... High magnetic permeability thin film, 1
5... Thin film coil, 16... Coil (for recording),
17, 18... conductive film, 19... dielectric protective film,
20, 21... Insulating film, 22... Protective film, 23...
...Ferrite, 24... Perpendicular magnetic recording layer, 25...
...Recording medium base material, 27...Movement direction of the recording medium.

Claims (1)

[Scope of Claims] 1. In a single-pole magnetic head for recording and reproducing information on a perpendicular recording medium having perpendicular magnetic anisotropy, a main magnetic pole consisting of a plurality of spaced apart high magnetic permeability thin films is in contact with the recording medium. A coil wound around the main magnetic pole is arranged only on one side of the recording medium, and the main magnetic pole and the coil record with a predetermined width, and the magnetic pole width is smaller than the predetermined width. A magnetic head characterized in that reproduction is performed by a coil formed of a magnetic pole that is a part of the main magnetic pole and a thin film wound around the tip of the magnetic pole.