JPS6381617A - Single magnetic pole type magnetic head for perpendicular recording - Google Patents

Abstract

PURPOSE:To obtain a head having a high sensitivity by extending a soft magnetic substance layer to an opposed face and forming the space between a main magnetic pole and the above-mentioned layers so as to be unequal in a track width direction. CONSTITUTION:When a current is made to flow through a coil 5, the main magnetic pole 1 and the return path part 2b of the soft magnetic substance layer 2 are excited by the part of the opposed face of a magnetic recording medium and the part 2a on the opposite side of the soft magnetic substance layer 2 is excited by the rear part of the coil 5. A magnetic flux generated by the excitation of the main magnetic pole 1 and the soft magnetic resubstance layer 2 is focused on the head part 1a of the main magnetic pole 1 and it executes effective recording in the perpendicular magnetic recording layer 13 of a magnetic recording medium 10. And the reture path 2b of the soft magnetic substance layer 2 is made to tilt against the main magnetic pole 1 and formed to have an azimuth so as to obtain an easy waveform of a sub pulse. Now, it is desirable that the width l of the tilt of the return path part 2b is made longer recorded waveform.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a single-pole magnetic head for perpendicular recording used in a perpendicular recording method that magnetizes and records in a direction perpendicular to a recording medium.

[Summary of the invention]

The present invention provides a single-pole magnetic head for perpendicular recording in which a main pole and a soft magnetic layer serving as a retard path portion extend on a surface facing a magnetic recording medium, in which an interval between the main pole and the soft magnetic layer is provided. This is intended to reduce sub-pulses in the return path section, thereby reducing waviness in wavelength characteristics and peak shifts during digital recording by setting them to be non-uniform in the track width direction.

[Conventional technology]

Conventionally, in order to perform recording and reproduction on magnetic recording media used as recording media for computers (Q media, audio tape recorders, video tape recorders, etc.), the magnetic layer deposited on the substrate was magnetizes inward,
Generally, recording and reproduction are performed using residual magnetization in the in-plane direction.

However, in the case of recording using in-plane direction magnetization, as the wavelength of the recording signal becomes shorter, that is, as the recording density increases, the demagnetizing field within the medium increases and the residual magnetic flux density attenuates.
This has the disadvantage that the reproduction output is reduced.

Therefore, a perpendicular magnetic recording method has been proposed in which recording and reproduction are performed by magnetization in the thickness direction of the magnetic layer of a magnetic recording medium.

According to the above, as the recording wavelength becomes shorter, the demagnetizing field becomes smaller, and this method is more advantageous than the above-mentioned recording using in-plane direction magnetization, especially in high-density recording, and therefore, research is actively underway.

As perpendicular recording magnetic heads used in this type of recording system, auxiliary magnetic pole excitation type magnetic heads have also been prototyped, but since this type of magnetic head has a structure in which the medium is sandwiched, it is difficult to use for hard disk drives or multi-channel (multi-track) devices. )
Because it is difficult to use in magnetic tape devices and the like, a single-pole magnetic head, which is one-side excitation type, has been proposed. For example, Japanese Patent Publication No. Sho 61-18249 proposes a single-pole type magnetic head in which a main pole, a coil donor for exciting the main pole, and the like are formed of thin films to form a thin film head.

[Problem that the invention seeks to solve]

Incidentally, such single-pole magnetic heads are usually used in combination with a two-layer perpendicular magnetic recording medium lined with a high magnetic permeability layer, and the high magnetic permeability layer of the medium is used to direct the magnetic flux path during recording and reproduction. By doing so, it is possible to obtain a recording efficiency comparable to that of a ring type head, and to obtain a reproduction output with a good S/N ratio.

In this case, conventionally, in order to improve the recording and reproducing sensitivity, the coercive force Hc of the high magnetic permeability layer on the medium side is reduced, and a two-layer medium is manufactured under conditions such that the magnetic permeability of the high magnetic permeability layer increases. was common.

However, further research revealed that if the coercive force Hc of the high permeability layer of the two-layer medium is reduced, the i! Eff
It has become clear that noise is generated by the interlayer, and in order to suppress the noise generation, it is necessary to slightly increase the coercive force He of the high magnetic permeability layer. This means that the magnetic permeability of the high magnetic permeability layer has to be lowered, resulting in a new problem of reduced recording and reproducing sensitivity.

Therefore, it is necessary to increase the sensitivity of the magnetic head that performs recording and reproduction to cope with the above-mentioned decrease in magnetic permeability of the high magnetic permeability layer.

The requirements for increasing the sensitivity of a single-pole magnetic head are that the return path section must be exposed to the surface facing the magnetic recording medium;
The distance between the main magnetic pole and the return path part is several μm,
However, if the return path portion is exposed to the surface facing the magnetic recording medium in order to increase the sensitivity, sub-pulses are generated due to the influence of the return path portion. Then, as the return path section is brought closer to the main magnetic pole in order to improve the sensitivity, the sub-pulses become larger, causing a problem in that the wavelength characteristics are undulated. When digital recording is performed using such a head, a problem arises in that the peak shift increases, which is inconvenient in practice.

Therefore, the present invention was proposed in view of the conventional situation, and aims to eliminate the influence of sub-pulses caused by exposing the return path portion to the surface facing the magnetic recording medium, and to eliminate the effects of sub-pulses that occur by exposing the return path portion to the surface facing the magnetic recording medium. An object of the present invention is to provide a single-pole magnetic head for perpendicular recording that has no peak shift during digital recording.

[Means for solving problems]

The inventors of the present invention have conducted intensive research over a long period of time in order to develop a single-pole magnetic head that is less affected by sub-pulses, and have come to the following findings.

In other words, the sub-pulses generated by the return path section cannot essentially be eliminated unless the return path section is retreated from the surface facing the magnetic recording medium, but normally in digital recording, information is assumed to be at the peak position of the reproduced waveform and differentiated. Since detection is performed, the problem is not the absolute level of the waveform but the steepness of the waveform.

Therefore, if the sub-pulses have a gentle waveform, even if the sub-pulses exist, their influence can be virtually ignored.

The present invention has been completed based on this knowledge, and includes a main magnetic pole formed of a soft 611 thin film with one end extending to an opposing surface facing a magnetic recording medium, and a main magnetic pole centered on the other end of the main magnetic pole. A winding that is insulated from the main magnetic pole and magnetically coupled to the main magnetic pole at the other end of the main magnetic pole. ! a soft magnetic layer extending toward the opposing surface so as to face the 5 wire, and the soft magnetic layer extends to the opposing surface, and the distance between the soft magnetic layer and the main magnetic pole is equal to the track width. It is characterized by being formed so as to be non-uniform in the direction.

[Effect]

The single-pole type magnetic head of the present invention has a structure in which the soft magnetic layer serving as the return path portion is exposed on the head surface and is close to the main pole, thereby achieving high sensitivity.

In the present invention, since the spacing between the main pole and the soft magnetic layer forming the return path section is made non-uniform in the track width direction, the sub-pulses generated at the edges of the return path section are used for magnetic recording. The shape is dispersed in the medium running direction, resulting in a gentle waveform. In other words, making the spacing between the main 6n poles and the return path section uneven means that the distance between them is shifted in the trunk width direction, and the phase of the reproduction output is shifted, which is called azimuth. It is thought that the effect of subpulses is eliminated by an effect similar to that of loss.

〔Example〕

Hereinafter, specific embodiments of a single pole type magnetic head to which the present invention is applied will be described.

As shown in FIG. 1, the single-pole magnetic head of this embodiment has a main pole (1) and a soft magnetic layer (2) that becomes the return path.
) etc. were produced using thin film formation technology.

That is, on a non-magnetic base Fi (3) such as ceramics, a main magnetic pole (
1) is formed by adhesion, and its tip (1a) extends to the surface facing the magnetic recording medium (10), and faces the surface facing the magnetic recording medium as a recording/reproducing section.

Note that recording and
The magnetic recording medium to be reproduced has a high magnetic permeability layer (12) made of permalloy (Fe-Ni alloy) or the like on a base (11).
It is a perpendicular magnetic recording medium with a two-layer structure in which a perpendicular magnetic recording layer (13) such as a Co--Cr alloy film is deposited.

The tip (1a) of the main magnetic pole (1) is set thinner than the other parts of the main magnetic pole (1), and the magnetic flux is focused in this part, resulting in efficient recording due to the steep magnetic field.・It is configured so that it can be played back.

On the other hand, on the main magnetic pole (1), a second magnetic thin film is formed as a soft magnetic layer (2) via an insulating layer (4), and a connection provided on the insulating layer (4) is formed. It is magnetically coupled to the rear end side of the main pole (1) at the window (4a).

The soft magnetic layer (2) has a portion (2a) extending on the opposite side from the main magnetic pole (1) and a portion (2b) extending to the opposing surface of the magnetic recording medium similarly to the main magnetic pole. The portion (2b) extending to the surface facing the magnetic recording medium is exposed to the surface facing the magnetic recording medium and serves as a return path section.

Further, a spiral coil (5) is similarly arranged between the main pole (1) and the soft magnetic layer (2) with an insulating layer interposed therebetween. This coil (5) is formed by depositing a conductive metal such as copper or aluminum by methods such as plating, vapor deposition, or spackling, and etching it into a predetermined spiral pattern using photolithography.
A wire is wound on the rear end side of the main pole (1) centering around the joint with the soft magnetic layer (2). Of course, this coil (5) does not necessarily have to be one layer, and may be stacked with two or three layers to increase the number of windings.

Therefore, when a current is passed through the coil (5), the return path portion (2b) of the main pole (1) and the soft magnetic layer (2) is connected to the portion (2b) of the coil (5) on the side facing the magnetic recording medium. 5a), and the opposite part (2a) of the soft magnetic layer (2) will be excited by the rear part (5b) of the coil (5). In any case, the magnetic flux generated by excitation of the main pole (1) and the soft magnetic layer (2) is focused on the tip (1a) of the main pole (1), and is perpendicular to the magnetic recording medium (10). It is configured to perform efficient recording on the magnetic recording layer (13).

The above-mentioned main magnetic pole (1), soft magnetic layer (2), and coil (5) are protected by bonding a protective plate (6) made of ceramics or the like to prevent accidental damage to the F member. suppressed.

The single-pole magnetic head with the above configuration has a magnetic circuit similar to a closed structure like a ring-type magnetic head, so
This results in excellent recording and reproducing efficiency, but in order to further improve the reproducing efficiency, the main magnetic pole (1) and the soft magnetic layer (2) on the surface facing the magnetic recording medium [here exposed on the surface facing the magnetic recording medium] An important factor is the spacing between the return path sections (2b). Therefore, in order to achieve high sensitivity,
It is necessary to set the above-mentioned interval to about several 11 meters, but in this case, the influence of sub-pulses generated at the edges of the return path section (2b) becomes a problem.

Therefore, in the present invention, the sub-pulses in the return path section (2b) have a gentle waveform to suppress the influence thereof.

As a method of making the sub-pulses have a gentle waveform, for example, a method of slightly retracting the return path portion (2b) from the surface facing the magnetic recording medium can be considered.

This causes a spacing loss and the waveform becomes gentle. However, if the return path section (2b) is retracted, there is a problem that the sensitivity deteriorates, so it is necessary to keep the amount of retraction to about 1 μm, which causes problems in processing accuracy and wear even if manufacturing is possible. Considering the above, it is not practical. Another possible method is to round the edges of the return path part (2b), but it is also difficult to process and
Not practical when considering wear and tear.

In the present invention, as shown in FIG. 2, the return path part (2b) of the soft magnetic layer (2) is tilted with respect to the main magnetic pole 1) to have an azimuth shape, and the waveform of the sub-pulse is Make it gentle. In this case, it is preferable that the width l of the slope of the return path section (2b) is longer than the longest recording wavelength.

The present inventors simulated the relationship between the structure of the return path section of a single pole magnetic head and the reproduction sensitivity, and analyzed the above-mentioned azimuth effect. The simulation method used was magnetic field analysis using the two-dimensional finite element method.

Also, in the simulation, the main in(.

The magnetic bodies such as the magnetic body and the return path part (2b) were assumed to have a constant magnetic permeability, ignoring magnetic saturation and nonlinear characteristics. +1 for the magnetic head used in the analysis! The structure is schematically shown in Figure 3. Here, the head-medium spacing W is 0.
1 μm, the film thickness of the perpendicular magnetic recording layer (13) is 0.15
μm, the tip of the main pole (1) and the high advancement (multilayer (12
) was set to 0.25 μm. In addition, the main magnetic pole (1)
Film thickness: 025 μm, main pole (1) and soft magnetic layer (2)
The magnetic permeability of the magnetic recording medium (10) is 2000, and the magnetic permeability of the high magnetic permeability layer (12) of the magnetic recording medium (10) is 100 (both 2.5 Mllz
(measured value). Furthermore, the coil (5) has 0.1
The origin of A (d power is given).

First, in a magnetic head in which the main 6 (i-pole (1) and return path part (2b) are arranged in parallel), when a constant excitation current is passed through the coil (5), the main magnetic pole (1) and the return path part (2b) are arranged in parallel. The magnitude of the vertical component (component in the direction of the arrow X in the figure) of the magnetic field emitted from (2b) is as shown in Figure 4. In this Figure 4, the horizontal axis is in the X direction in Figure 3. The right end position of the tip (1a) of the main (1) in the figure is x=Q.

In other words, the reciprocity theorem states that the perpendicular magnetic field component (I-1y) is equal to the reproduced waveform of a solitary wave in perpendicular recording, so in Fig. 4, the reproduced waveform (positive side waveform) due to the main magnetic pole (1) is returned. The sub-pulse (
It can be seen that the negative side waveform) is a synthesized waveform.

Here, the sub-pulses generated by the return path section (2b) are:
As the return path section (2b) is moved away from the main pole (1), it gradually shifts to the right in the figure, as shown by a, b, c, d, and e in FIG. In addition, for a to e, the distance G between the main magnetic pole (1) and the return path part (2b) is 3 μm.
, 4 μm, 5 μm, 6 μm, and 7 μm.

Such sub-pulses cause a beak shift during high-density recording. That is, in actual data detection, a method of differentiating the reproduced waveform and detecting zero crossing points is used, so the differential waveform becomes a problem, but as shown in Fig. 4, the differential waveform of the reproduced waveform having subpulses is In addition to the original signal, there are sub-pulses by the return bus section (2b), so the gear length from the data point is approximately c.The distance between the main magnetic pole (1) and the return bus section (2b). ] An unnecessary pulse is generated at a position far away. Figure 4 shows the reproduced waveform for a solitary wave, but in actual recording, data is recorded continuously, so if the next data is written exactly at the sub-pulse position, the reproduced waveform will be the original data waveform. The sub-pulse waveform is added to the sub-pulse waveform, and the point shifted by the peak value of the sub-pulse becomes the atmosphere cross position, resulting in a peak shift of that amount.

On the other hand, as shown in Figure 2, the return bus section (2
When the distance between the main magnetic pole (1) and the return bus section (2b) is made uneven by giving an azimuth to b), the sub-pulses generated at the return bus section (2b) have a gentle waveform. FIG. 5 shows the magnetic field distribution (isolated waveform) obtained by linearly changing the gap length G between 3 and 7 μm (corresponding to the slope width a=4 μm). From FIG. 5, it can be seen that the sub-pulse portion has a very gentle shape. The waveform obtained by differentiating this is shown in FIG. As a result, the peak value of the sub-pulse portion is significantly reduced.

That is, it is shown that by providing the return bus section (2b) with azimuth, the influence of sub-pulses generated by the return bus section (2b) can be significantly reduced.

Moreover, a sufficient effect can be observed when the value of the slope is about several μm.

As can be seen from the previous explanation, in order to make the knob pulse a gentle waveform, it is sufficient to make the spacing of the return bus section (2b) uneven with respect to the main magnetic pole (1) and disperse the sub-pulses. , Therefore, in addition to providing an azimuth as shown in FIG. 2, various modifications can be considered. That is, the return bus section (2b) may have any shape as long as it has an azimuth with a predetermined slope width, and for example, the shape does not need to be exactly straight. Fig. 7A shows the return bus section (2b) bent so that the center part in the track width direction is the farthest position from the main magnetic pole (1), and Fig. 7B shows the return bus section conversely. (
2b) is bent so that the center portion in the track width direction is located closest to the main &i pole (1). In addition, Fig. 7C shows the return bus part (2b) with an innocent shape, Fig. 7 shows the return bus part (2b) with an arc shape, and Fig. 7E shows the return bus part (2b) with an innocent shape. Only the opposite edges of the main magnetic pole (1) are bent obliquely. In any of these cases, the sub-pulse waveform generated in the return bus section (2b) is dispersed in the direction in which the magnetic recording medium runs by the magnetic head and becomes gentle. however,
In order to make the existence probability of the gear knob length G uniform, it is preferable that the edge of the return bus section (2b) facing the main magnetic pole (1) be a straight line. Note that it is sufficient that the above-mentioned azimuth (inclination) is provided only on the magnetic recording medium facing surface of the return bus section (2b). There is no need to provide a bevel, and it may be parallel to the main magnetic pole (1).

Although specific embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments and can be modified without departing from the gist of the present invention.

〔Effect of the invention〕

As is clear from the above description, in the single-pole magnetic head of the present invention, the soft magnetic layer that is magnetically coupled on the rear end side of the main pole extends to the surface facing the magnetic recording medium, and Since the spacing between the soft magnetic material layer and the main pole is made non-uniform in the track width direction, it is possible to make the sub-pulses generated in the soft magnetic material layer forming the return bus part have a gentle waveform. can.

Therefore, it is possible to provide a single-pole magnetic head that has a high degree of excitation and exhibits less waviness in wavelength characteristics and less peak shift during digital recording.

4. Sectional explanation of the 7th aspect Figure 1 applies the present invention. ! FIG. 2 is an enlarged sectional view of the main part of an example of a Jl magnetic pole type magnetic head, and FIG. 2 shows the arrangement of the main magnetic scratches and the soft magnetic layer on the surface facing the magnetic recording medium. FIG. 3 is a schematic plan view showing an enlarged view.

FIG. 3 is an enlarged schematic diagram showing the vicinity of the surface facing a magnetic recording medium of a single-pole magnetic head to which the present invention is applied.

FIG. 4 is a characteristic diagram showing the magnetic field distribution when the main (H pole) and the return bus section are arranged in parallel.

Figure 5 shows the result when the return bus section has azimuth ((
FIG. 6 is a characteristic diagram showing the i-field distribution, and FIG. 6 is a characteristic diagram showing its differential waveform.

FIGS. 7A to 7E are schematic plan views showing other examples of the shape of the return bus section.

l...Main magnetic pole 2...Soft magnetic layer 5...Coil Figure 1 Figure 2 Figure 3 Figure 4 salt 5 diagram Figure 6 Figure 7 People Figure 7 B Figure 7 C Figure 7D Figure 7E

Claims (1)

[Claims] A main magnetic pole formed of a soft magnetic thin film and having one end extending to an opposing surface facing a magnetic recording medium, and a winding formed insulated from the main magnetic pole around the other end side of the main magnetic pole. and a soft magnetic material layer that is magnetically coupled to the main magnetic pole on the other end side of the main magnetic pole and extends to the opposing surface side so as to face the winding, 1. A single-pole magnetic head for perpendicular recording, characterized in that the body layer extends to the opposing surface and is formed so that the spacing between it and the main pole is non-uniform in the track width direction.