JPH07225912A - Thin-film magnetic head for perpendicular magnetic recording - Google Patents

Abstract

PURPOSE:To improve recording and reproducing characteristics by providing an auxiliary magnetic pole with a projecting part, thereby shortening the spacing between the auxiliary magnetic pole (projecting part) and a main magnetic pole and averting leakage of magnetic fluxes without shortening the length of cores. CONSTITUTION:The auxiliary magnetic pole 5 of the thin-film magnetic head for perpendicular magnetic recording is provided with the projecting part 5a at the end of a recording medium and is formed to an approximately L shape. The spacing between projecting part 5a and the main magnetic pole 1 is set at, for example, 15 to 60mum. As a result, the spacing between the main magnetic pole 1 and the auxiliary magnetic pole 5 is shortened and the leakage of the magnetic fluxes is suppressed without decreasing the winding number of coil 7. The recording and reproducing characteristics are thus improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to perpendicular magnetic recording used in a perpendicular magnetic recording system in which a magnetic material in a recording layer provided on a magnetic recording medium is magnetized in a direction perpendicular to the surface of the magnetic recording medium. The present invention relates to a thin film magnetic head.

[0002]

2. Description of the Related Art Conventionally, as a magnetic recording system, a magnetic material is magnetized in a horizontal direction (plane direction) with respect to a surface of a magnetic recording medium, and data is recorded / reproduced by residual magnetism in a plane direction of a recording layer. The magnetic recording method is generally used.

In recent years, the recording density of magnetic recording media has tended to increase. However, in the longitudinal magnetic recording method, when the recording density becomes high, the demagnetizing field relative to the residual magnetization becomes relatively large, so that there is a problem that the residual magnetic flux density is attenuated and the reproduction output is lowered. Therefore, in recent years, a perpendicular magnetic recording system in which a magnetic material is magnetized in a direction perpendicular to the surface of a magnetic recording medium has been attracting attention. In this perpendicular magnetic recording system, even if the recording density becomes high and the recording bit becomes small, it is difficult to be affected by the demagnetizing field, and it is possible to avoid a decrease in the residual magnetic flux density.

FIG. 2 is a schematic sectional view showing a conventional thin film magnetic head for perpendicular magnetic recording used in a perpendicular magnetic recording system. The main magnetic pole 1 and the auxiliary magnetic pole 5 serving as a magnetic flux return path for the main magnetic pole 1 are arranged apart from each other in a direction parallel to the surface of the magnetic recording medium 8. A core 6 around which a coil 7 is wound is arranged between the main magnetic pole 1 and the auxiliary magnetic pole 5. A yoke 2 for collecting the magnetic flux generated in the core 6 at the tip of the main magnetic pole 1 is provided on the side of the main magnetic pole 1 opposite to the auxiliary magnetic pole 5. The tip of the main magnetic pole 1 extends below the yoke 2 (on the side of the magnetic recording medium 8). The coil 7 is embedded in an insulating layer (not shown) provided between the auxiliary magnetic pole 5 and the main magnetic pole 1. Further, the magnetic recording medium 8 is composed of a recording layer 3 made of a magnetic material and a high magnetic permeability layer 4 as an underlayer for the recording layer 3.

In the thin film magnetic head having the above-described structure, induced magnetization is generated in the core 6 by an electric signal flowing in the coil 7 when writing data. The magnetic flux due to the induced magnetization passes through the main magnetic pole 1 and the yoke 2, goes out of the head from the tip of the main magnetic pole 1, penetrates the recording layer 3 of the magnetic recording medium 8, and changes the direction through the high magnetic permeability layer 4. , Recording layer 3 again
Through the auxiliary magnetic pole 5, and returns to the core 6 through the auxiliary magnetic pole 5. That is, a closed magnetic circuit is formed in which the magnetic flux generated in the core 6 passes through the main magnetic pole 1, the auxiliary magnetic pole 2, the recording layer 3, and the high magnetic permeability layer 4, and further returns to the core 6 through the recording layer 3 and the auxiliary magnetic pole 5. It In this case, the magnetic flux emitted from the tip of the main pole 1 passes through the recording layer 3 in its thickness direction,
The magnetic substance in the recording layer 3 is magnetized in the direction perpendicular to the surface of the magnetic recording medium 8. By moving the magnetic recording medium 8 relative to the thin film magnetic head, data corresponding to the electric signal is recorded on the recording layer 3 as magnetic data.

On the other hand, the data recorded on the magnetic recording medium 8 is reproduced as follows. That is, the magnetic flux emitted from the magnetic material in the recording layer 3 passes through the main magnetic pole 1 and the yoke 2,
It flows through the core 6, passes through the auxiliary magnetic pole 5, and returns to the magnetic body again.
At this time, the magnetic flux is changed by moving the magnetic recording medium relative to the thin film magnetic head. Due to this change in magnetic flux, an induced current is generated in the coil 7, and an electric signal corresponding to the data is obtained. In this way, the data is reproduced.

[0007]

However, in the above-described conventional thin film magnetic head for perpendicular magnetic recording, there is a problem that the loss of the magnetic flux due to the leakage of the magnetic flux is large. Therefore, in the conventional thin film magnetic head for perpendicular magnetic recording, the amount of magnetic flux that contributes to recording / reproduction is small, and the recording / reproduction output is not sufficient. That is, in the conventional thin film magnetic head for perpendicular magnetic recording, the distance between the main magnetic pole and the auxiliary magnetic pole is large, and the magnetic flux leaving the main magnetic pole leaks to the outside without going to the recording medium or passes through the high magnetic permeability layer. Since the magnetic flux is not sufficiently collected by the auxiliary magnetic pole, the recording / reproducing characteristics are not sufficient as described above. Although it is possible to reduce the leakage of magnetic flux by shortening the distance between the main pole and the auxiliary pole, doing so shortens the length of the core, and the number of turns in the coil must be reduced. Alternatively, the induced magnetization due to the current flowing through the core is reduced and the recording / reproducing output is reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a thin film magnetic head for perpendicular magnetic recording in which leakage of magnetic flux is small and recording / reproducing characteristics are excellent.

[0009]

In a thin-film magnetic head for perpendicular magnetic recording according to the present invention, a main magnetic pole and an auxiliary magnetic pole facing the main magnetic pole are arranged with their facing directions parallel to the surface of a magnetic recording medium. In the thin-film magnetic head for perpendicular magnetic recording as described above, the auxiliary magnetic pole is provided with a protrusion that protrudes toward the main magnetic pole.

[0010]

In the thin-film magnetic head for perpendicular magnetic recording according to the present invention, since the auxiliary magnetic pole is provided with the protruding portion, the auxiliary magnetic pole (projecting portion) and the main magnetic pole are not shortened without shortening the length of the core. The interval can be shortened. This allows
The length of the closed magnetic circuit is shortened, leakage of magnetic flux can be avoided, and recording / reproducing characteristics can be improved. Further, when the distance between the protrusion and the main magnetic pole is set to be the same as the distance between the auxiliary magnetic pole and the main magnetic pole in the conventional perpendicular magnetic recording thin film magnetic head, the core disposed between the main magnetic pole and the auxiliary magnetic pole is The length is increased, and the number of turns of the coil can be increased. Also in this case, the recording / reproducing characteristics are improved.

The distance between the protrusion and the main pole is 15
When it is less than μm, the peak shift amount becomes large. On the other hand, when the distance between the protrusion and the main magnetic pole exceeds 60 μm, the recording / reproducing output becomes small. Therefore, the distance between the protrusion and the main pole is preferably 15 to 60 μm. A more preferable distance between the protrusion and the main pole is 25 to 40 μm.

[0012]

Embodiments of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a schematic sectional view showing a thin film magnetic head for perpendicular magnetic recording according to an embodiment of the present invention. The present embodiment is different from the conventional one in that the auxiliary magnetic pole 5 is provided with a protruding portion 5a protruding toward the main magnetic pole 1 at the end portion on the magnetic recording medium side, and other configurations are basically conventional. 1 are the same as those in FIG. 2, and the same reference numerals are given to those same as those in FIG.

The auxiliary magnetic pole 5 of the thin film magnetic head for perpendicular magnetic recording according to this embodiment has a protrusion 5a at the end on the recording medium 8 side.
Is provided and is formed in a substantially L shape. The distance between the protrusion 5a and the main pole 1 is, for example, 15 to 60 μm.
It is set to m.

In this embodiment, since the auxiliary magnetic pole 5 is provided with the projecting portion 5a, the distance between the main magnetic pole 1 and the auxiliary magnetic pole 5 can be reduced without reducing the number of turns of the coil 7. it can. Thereby, leakage of magnetic flux can be suppressed, and recording / reproducing characteristics are improved. Also, the main pole 1
When the distance between the auxiliary magnetic pole 5 and the auxiliary magnetic pole 5 is the same as that of the conventional thin film magnetic head for perpendicular magnetic recording, the length of the core 6 is increased by the protruding length of the protruding portion 5a. You can In this case also, the induced magnetization due to the induced current generated in the coil 7 or the current flowing in the coil 7 increases,
Recording / reproducing characteristics are improved. Therefore, the thin film magnetic head according to the present embodiment can obtain a large recording / reproducing output even if the main magnetic pole width (track width) becomes narrower in response to the improvement in recording density, and the thin film magnetic head for high density recording can be obtained. Excellent as a head.

The method of manufacturing the thin film magnetic head according to this embodiment will be described below. First, a NiFe thin film to be an auxiliary magnetic pole is formed in a predetermined pattern on a supporting member (not shown) by plating. Next, on this NiFe thin film,
A mask is formed with a pattern of cores and protrusions using photolithography technology. Then, NiFe plating is performed to form a core and a protrusion. However, if the pattern shapes of the core and the protrusions are largely different from each other, it may not be possible to obtain a predetermined iron composition. Therefore, it is not always necessary to form the core and the protrusions at the same time. Further, the auxiliary magnetic pole and the core may be formed using a vacuum thin film forming technique such as sputtering. Further, after forming the core to a certain thickness, the coil and the insulating film are formed. By repeating such an operation, a core is formed and a coil having a predetermined number of turns is formed.

Next, a photolithography technique is used to form a mask with the pattern of the main pole. Then, for example, CoZrNb is sputtered and the mask is removed to obtain the main pole. Next, a mask is formed on the main magnetic pole in a yoke pattern. Then, for example, CoZrNb is sputtered and the mask is removed to obtain a yoke. As a result, the thin film magnetic head for perpendicular magnetic recording according to this embodiment is completed. The yoke may be formed by NiFe plating, for example.

The results of actually manufacturing the thin-film magnetic head according to this embodiment and examining its characteristics will be described below in comparison with a comparative example.

First, as described above, the auxiliary magnetic pole 5, the core 6 and the coil 7 were formed by plating. The coil has 6 layers and the total number of turns is 60 turns. Then, CoZrNb was sputtered to form the main pole 1 with a thickness of 0.2 μm. Next, CoZrNb was sputtered on the main pole 1 to form the yoke 2 with a thickness of 1 μm. Thus, as shown in Table 1 below, the thin film magnetic heads of Examples 1 to 5 in which the distance between the auxiliary magnetic pole and the main magnetic pole was 5 to 65 μm were obtained. The thickness of each protrusion (thickness of the protrusion perpendicular to the surface of the magnetic recording medium) is about 5 μm. Further, as Comparative Example 1, the core length and the number of turns of the coil are the same as those of Examples 1 to 5 (6 layers and the total number of turns is 60 turns).
Thus, a thin film magnetic head having no protrusion on the auxiliary magnetic pole was formed.

The reproducing output and the peak shift amount of the thin film magnetic heads of Examples 1 to 5 and Comparative Example 1 manufactured as described above were measured. The reproduction output was measured under the condition that the relative speed between the head and the recording medium was 4.5 m / sec, and the peak shift amount was measured in 110 patterns at 80 kfci. The results are also shown in Table 1.

[0020]

[Table 1]

It can be seen from Table 1 that the reproduction output increases as the distance between the auxiliary magnetic pole and the main magnetic pole decreases.
However, when the distance between the auxiliary magnetic pole and the main magnetic pole is less than 15 μm, the peak shift abruptly increases, and when the distance between the auxiliary magnetic pole and the main magnetic pole exceeds 60 μm, there is little effect of increasing the reproduction output. The peak shift is related to the accuracy of data discrimination, and it is not preferable that the peak shift becomes large.
Therefore, the distance between the auxiliary magnetic pole and the main magnetic pole is 15 to 60 μm.
It is preferably m. Further, when the distance between the auxiliary magnetic pole and the main magnetic pole is 25 to 40 μm, the reproduction output is large and the peak shift amount is small. Therefore, it is more preferable that the distance between the auxiliary magnetic pole and the main magnetic pole is 25 to 40 μm.

Generally, the reproduction output increases in proportion to the number of turns of the coil. Therefore, by providing the auxiliary magnetic pole with a protrusion as in the present invention, the coils are laminated without increasing the distance between the auxiliary magnetic pole and the main magnetic pole. The number can be increased, and the total number of turns of the coil can be increased to improve the reproduction output.
However, if the number of turns of the coil exceeds 60 turns, for example,
The inductance of the head becomes large, which makes it difficult to record / reproduce data at a high transfer rate. Therefore, it is not preferable to excessively increase the number of coil turns.

Next, the number of turns of the coil is set to the values in the first to fifth embodiments described above.
As shown in Table 2 below, the distance between the protrusion of the auxiliary magnetic pole and the main magnetic pole is 20 to 35
μm, 4 layers of coil stack (40 turns of coil)
A thin film magnetic head was manufactured. Then, the reproduction output and peak shift of these thin film magnetic heads are calculated as in the first embodiment.
It investigated similarly to -5. Further, as Comparative Example 2, the protrusion is not provided and the distance between the main magnetic pole and the auxiliary magnetic pole is 4
A 5 μm thin film magnetic head was manufactured, and its reproduction output and peak shift were examined. The results are shown in Table 2 below.

[0024]

[Table 2]

As is apparent from Table 2, in Examples 6 to 9 in which the auxiliary magnetic pole was provided with the protrusion, a larger reproduction output could be obtained than in Comparative Example 2 having no protrusion.

Next, a thin film magnetic head having a gap between the auxiliary magnetic pole (protrusion) and the main magnetic pole of 45 μm and a thickness of the protrusion (thickness in the direction perpendicular to the surface of the magnetic recording medium) of 1 μm, 6 μm and 11 μm is used. After manufacturing, the relationship between the thickness of the protrusion and the reproduction output was examined. As a result, the reproduction outputs of these magnetic heads were almost the same. That is, the reproduction output hardly depends on the thickness of the protruding portion, and if the distance between the auxiliary magnetic pole and the main magnetic pole is the same, the reproduction output is almost the same. From this, it is understood that the thickness of the protrusion is not limited.

[0027]

As described above, in the present invention,
Since the auxiliary magnetic pole is provided with the protruding portion that protrudes toward the main magnetic pole, it is possible to appropriately set the interval between the auxiliary magnetic pole and the main magnetic pole without reducing the number of turns of the coil. It is possible to obtain a thin-film magnetic head for perpendicular magnetic recording with little leakage and high recording / reproducing output. Therefore,
The thin film magnetic head according to the present invention can obtain a large reproduction output even if the width of the main magnetic pole is narrowed in response to the improvement in recording density, and is extremely excellent as a thin film magnetic head for high density recording.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a thin film magnetic head for perpendicular magnetic recording according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a conventional thin film magnetic head for perpendicular magnetic recording.

[Explanation of symbols]

 1; Main magnetic pole 2; Yoke 3; Recording layer 4; High permeability layer 5; Auxiliary magnetic pole 6; Core 7; Coil 8; Magnetic recording medium

Claims (2)

[Claims] 1. A perpendicular magnetic recording thin-film magnetic head in which a main magnetic pole and an auxiliary magnetic pole facing the main magnetic pole are arranged with their facing directions parallel to the surface of a magnetic recording medium. A thin-film magnetic head for perpendicular magnetic recording, comprising a protrusion protruding toward the main pole. 2. The distance between the protrusion and the main magnetic pole is 15
The thin-film magnetic head for perpendicular magnetic recording according to claim 1, wherein the thin-film magnetic head has a thickness of 60 to 60 μm.