JPH0448423A - Magnetic head and manufacture of the same - Google Patents

Abstract

PURPOSE:To prevent a crosstalk from generating in plural adjacent magnetic domains on a recording medium by making a magnetic gap part almost circular are corresponding to the shape of the magnetic domain on the recording medium. CONSTITUTION:Groups 2.2...and lands 3.3... are alternately formed on a substrate 5 at a prescribed pitch. Recording bits 1.1..., which shape almost circular- arc or crescent moon-shaped magnetic domains are formed along each land 3 so that information can be recorded. Then, a magnetic gap part 18 is almost circular arc corresponding to the shape of the magnetic domain on the recording medium. Thus, the crosstalk is prevented from generating in the plural adjacent magnetic domains on the recording medium, and a sufficient output of a regenerative signal can be obtained. Therefore, an accurate reproduction can be realized even when the recording bits shape the almost circular arc domains after recording density is hightened at an optical assisting magnetic recording.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head used for reproducing information recorded with optical assistance and a method of manufacturing the same.

[Background Art] In recent years, magneto-optical disks have been developed as recording media on which information can be recorded, reproduced, and erased. Magneto-optical disks usually use a perpendicularly magnetized film, and the perpendicularly magnetized film is heated by irradiation with laser light to lower its coercive force, and then an external magnetic field is applied to the perpendicularly magnetized film in a direction perpendicular to the film surface. , the direction of magnetization matches the direction of the external magnetic field to record information. On the other hand, during reproduction, information is detected based on the phenomenon that when the perpendicularly magnetized film is irradiated with laser light, the direction of rotation of the polarization plane of the reflected light differs depending on the direction of magnetization due to the so-called magneto-optic effect. will be held.

Recording methods for magneto-optical disks can be roughly divided into optical modulation methods, which modulate the intensity of laser light according to the information to be recorded while continuously applying an external magnetic field in a fixed direction, and optical modulation methods, which modulate the intensity of laser light according to the information to be recorded. There is a magnetic field modulation method in which the direction of the external magnetic field is reversed during irradiation depending on the information to be recorded. The above-mentioned magnetic field modulation method is considered to be a promising method for realizing override in which new information is directly recorded without erasing old information when rewriting recorded information.

In this magnetic field modulation method, in order to improve the recording density, by increasing the rotational speed of the disk or the frequency of magnetic field modulation, the recording magnetic domain length can be reduced to about 0.3 μm, which is a value smaller than the spont diameter of the laser beam on the recording medium. In that case, as schematically shown in Fig. 4,
It is known that the magnetic domains formed by recording pits 1... are arc-shaped or crescent-shaped (see 13th Japanese Society of Applied Magnetics, Academic Lecture Abstracts (1989), p. 198).

[Problem to be solved by the invention]

However, as mentioned above, when the recording pits 1... become arcuate and the magnetic domain length becomes short, when reproducing this with a laser beam, the laser spot becomes a plurality of recording pits 1, 1,... There is a problem in that individual recorded bits 1 cannot be reproduced because the beam is irradiated across the .

Therefore, it is conceivable to magnetically reproduce the information recorded in the recorded data 1 using a magnetic head without using laser light. However, in this case, since the recording pits 1 are arc-shaped, crosstalk tends to occur between adjacent recording pits 1 during playback, and the reproduction signal output also decreases, making accurate reproduction impossible. be.

(Means for Solving the Problems) In order to solve the above problems, a magnetic head according to the present invention is capable of reproducing information recorded in substantially arc-shaped magnetic domains on a recording medium by optically assisted magnetic recording. The magnetic head to be used includes a thin film core formed on a base material and having a magnetic gap portion having a substantially arc shape in the gap width direction corresponding to the shape of the magnetic domain on the recording medium, and this thin film core. The device is characterized in that it includes a reproducing coil that is provided so as to circulate.

In manufacturing the above-mentioned magnetic head, after etching a curved section having an approximately arc shape on the base material, a thin film core having a magnetic gap section is formed on the base material on which the curved section is formed. , it is preferable to provide the above-mentioned reproduction coil.

[For production]

In the magnetic head of the present invention described above, the magnetic flux from the magnetic domain on the recording medium is guided from the magnetic gap to the magnetic core, and a voltage is applied to the reproducing coil in accordance with a change in the magnitude of this magnetic flux. Since the voltage is induced, information on the recording medium can be detected based on this voltage. In this case, since the magnetic gap portion has a substantially arc shape corresponding to the shape of the magnetic domain on the recording medium, crosstalk does not occur between a plurality of adjacent magnetic sections on the recording medium.
Furthermore, it becomes possible to obtain a sufficient reproduction signal output. As a result, in optically assisted magnetic recording, accurate reproduction can be performed even when the recorded bits form a substantially arc-shaped magnetic domain as a result of increasing the recording density.

On the other hand, according to the method for manufacturing the magnetic head described above, first,
After forming a curved part on the base material in a shape corresponding to the magnetic domain on the recording medium which has a circular arc shape, a thin film core having a magnetic gap part is formed on the base material, so that the magnetic gap The portion can have a substantially arc shape corresponding to the shape of the magnetic domain on the recording medium.

[Example] An example of the present invention will be described below based on FIGS. 1 to 18.

As shown in Fig. 2, the optically assisted magnetic recording/reproducing device is
Recording and reproduction are performed on a disk 8 including a substrate 5, a recording film 6 as a recording medium formed on the substrate 5, and a protective film 7 for protecting the recording film 6. an optical head that irradiates the recording film 6 with a laser beam 10;
A floating magnetic head 11 is provided. The floating magnetic head 11 is supported by a suspension 12, and performs recording and reproduction while floating above the surface of the disk 8 as the disk 8 rotates.

As shown in FIG. 3, groups 2, 2... and lands 3, 3... are alternately formed at a predetermined pitch on the substrate 5, and along each land 3, the groups 2, 2,... and lands 3, 3... Recording pits 1 (see FIG. 4) forming magnetic domains are formed to record information.

As shown in FIG. 5, the floating magnetic helad 11 has a magnetic head body 14 mounted on a slider 13 that can slide on the disk 8.
The magnetic head main body 14 is equipped with a reproducing head section 15 for reproducing information.

As shown in FIGS. 1A and 1B, the reproducing head section 15 includes a substrate 16 (base material) made of MnZn ferrite or the like. A lower thin film core 17 is formed on the substrate 16, and an upper thin film core 20 is formed on the lower thin film core 17 with a gap layer 18 in between. The gap layer 18 constitutes a magnetic gap portion.

A reproducing coil 21 is formed of a thin film that goes around the upper thin film core 20, and a lead wire 22 made of a thin film is drawn out from the inner peripheral end of the reproducing coil 21. Upper thin film core 20 and lead extraction line 22
is covered with a protective layer 23. Furthermore, a protective layer 23
A protection plate 25 is bonded on top with a glass 24 interposed therebetween.

Note that, as is clear from the drawings such as FIG. 14(b), by forming a substantially arc-shaped convex portion 26 (curved portion) in advance on the substrate 16 as a base material, the lower thin film core 17 and the upper thin film The gap layer 18 between the cores 20 has a substantially arc shape corresponding to the recording bit 1 on the recording film 6 (see FIG. 4).

In the above configuration, when recording or playing back, the disk 8
As the slider 13 rotates (FIG. 2), the slider 13 floats above the surface of the disk 8. In this state, by applying an external magnetic field to the recording film 6 while irradiating the recording film 6 with a laser beam 10 from the optical head, almost arc-shaped recording pits 1 with high recording density are formed on the recording film 6. formed on top.

On the other hand, during reproduction, magnetic flux from each recording bit on the recording film 6 is transmitted from the magnetic gap portion (gap layer 18) between the lower thin film core 17 and the upper thin film core 20 in the reproducing head section 15 to the upper thin film core 20. be guided. Then, when the magnitude of the magnetic flux passing through the upper thin film core 2o changes,
Since the reproducing coil 21 generates a voltage according to the change, information on the recording y6 can be detected by detecting this voltage.

Next, a method of manufacturing the above-mentioned floating magnetic helad 11, particularly the reproducing head section 15, will be explained.

When manufacturing the reproducing head section 15, first, as shown in FIG. 6, a substrate 16 made of MnZn ferrite or the like is prepared, and a photoresist film 27 is formed on the surface of this substrate 16 so as to form a substantially arc shape. (Figure 7).

Then, when the substrate 16 is etched through the photoresist film 27 by ion milling or the like using Ar gas, a substantially arcuate convex portion 26 is formed on the surface of the substrate 16, as shown in FIG. Note that, instead of the convex portion 26, a concave portion having a circular arc shape may be formed. Further, in this embodiment, the convex portion 26 is formed over the entire length of the substrate 16, but the convex portion 26 may be formed only near the end of the substrate 16 on the side facing the disk 8.

Next, as shown in FIG.
A lower thin film core 17 (film thickness of about 2 μm) made of a soft magnetic material such as FeAfSi is formed on the substrate 6 by sputtering or the like. Note that on the substrate 16, first, Cr is applied as E B (
If the lower thin film core 17 is formed after being transformed by about 500 layers by electron beam (electron beam) evaporation, etc., the adhesion will be improved, so that the substrate 16 and the lower thin film core 1
It is preferable that a Cr film be interposed between the gaps 7 and 7. Further, in this embodiment, a magnetic material is used as the substrate 16, but when a non-magnetic material is used as the substrate 16, it is preferable that the film thickness of the lower thin film core 17 is about 10 μm.

After forming the lower thin film core 17, /M! , 03, etc. (thickness, for example, about 0.1 μm) is formed by Svantaling or the like. The thickness of the gap layer 18 is determined depending on the magnetic domain length of the recording bit 1 on the recording film 6.
It is preferable that the film thickness of No. 8 is smaller than the magnetic domain length.

Next, as shown in FIGS. 10(a) and 10(b), an insulating layer 28 (for example, about 2 um thick) made of 5iOz or the like is formed on the gap layer 18 by P-CVD (Plasma Ch).
It is formed by a chemical vapor deposition method or the like.

Subsequently, on the insulating layer 28, for example, Nb (0°05μ
m)/Cu (1μm)/Nb (0,1am)/Ti
A regeneration coil 21 having a spiral shape when viewed from above is formed by sequentially depositing a four-layer thin film (0.2 μm) by EB vapor deposition and removing unnecessary portions by ion milling or the like.

Next, as shown in FIG. 11, an insulating layer 28 (formed in multiple steps, but given the same number for convenience) made of 5iOz or the like is formed by coating or the like so as to cover the reproduction coil 21. After flattening, as shown in FIGS. 12(a) and 12(b), the areas 30 and 31 that will become the joining area between the upper thin film core 20 and the lower thin film core 17 and the inner peripheral side end of the regeneration coil 21 are The insulating layer 28 in the region 32 (shown by hatching in FIG. 12(a) for convenience) is removed by reactive ion etching or the like. As a result, areas 30 and 31
In this case, the gap layer 18 is exposed, and in the region 32, the reproduction coil 21 is exposed. Furthermore, as shown in FIG. 13, the gap layer 18 in the region 31 is removed by ion milling or the like to expose the lower thin film core 17 in the region 31.

Subsequently, as shown in FIGS. 14(a) to 14(C), the upper thin film core 20 is formed by a lift-off method using polyimide.
and a lead lead line 22 is formed. That is, the 13th
In the state shown in Figures (a) and (b), first, a polyimide layer is formed on the entire surface by spin cording, baking, etc., and then a Cu layer (film thickness 0.6μ) is formed on this polyimide layer by EB evaporation, etc.
m).

Subsequently, the above-mentioned Cu layer in the region corresponding to the formation site of the upper thin film core 20 and the lead extraction line 22 is removed by ion milling or the like, and furthermore, the polyimide layer in the region corresponding to the removed portion of the Cu layer is treated with reactive ions. Remove by etching etc.

And FeAj! The upper thin film core 20 and lead wires 22 are formed by Si sputtering or the like, unnecessary parts are removed together with the polyimide layer, and necessary heat treatment is performed.

The front end of the upper thin film core 20 formed as described above faces the lower thin film core 17 via the gap layer 18, and the rear end of the upper thin film core 20 faces the lower thin film core 17.
7. The front end of the lead wire 22 is joined to the inner end of the reproduction coil 21, passes over the reproduction coil 21, and is drawn out near the rear end of the substrate 16.

Further, since the convex portion 26 is provided in advance on the substrate 16, the gap layer 18 has a substantially arc shape corresponding to the shape of the recording bit 1 (FIG. 4) when viewed in the gap width direction.

After forming the upper thin film core 20 and the lead wire 22, as shown in FIG.
4 of Nb/Cu/Nb/Ti similar to
It is formed by EB vapor deposition of a thin layer.

The width of the front end of the upper thin film core 20 is approximately the diameter of the laser beam on the recording film 6 (1.5 μm or less).

On the other hand, although the width of the rear end portion of the upper thin film core 20 is slightly larger than the width in the drawing, it is actually set to be considerably larger than the width.

After forming the leads 33, as shown in Part 1), a protective layer 23 is formed by depositing a 5iOz layer on the entire surface including the upper thin film core 20, lead extraction lines 22, and leads 33 using the P-CVD method. (film thickness of about 1 μm) is formed. After that, areas 34 and 35 shown by hunting in FIG. 1(a)
The protective layer 23 in this area is removed by reactive ion etching or the like, and the reproduction coil 21 and lead 33 in this area are removed.
Let be the electrode terminal.

Next, a protective plate 25 made of MnZn ferrite or the like is adhered onto the protective layer 23 using glass 24 . At this time, the glass 24 is softened, for example, by heating it in a vacuum at about 550° C. for about 30 minutes, and then the protection plate 25 is bonded by applying pressure.

Note that in the above description, for convenience of explanation, the playback head section 15 is
The substrate 16 was formed one by one, but at the stage shown in FIG.
6 to 14(a) to 14(C) and the following FIG. In step a), a plurality of reproducing head sections 15 may be formed two-dimensionally at the same time, and then separated after the formation.

Next, the manufacturing process of the slider 13 will be explained.

First, for the slider material 41 as shown in FIG.
A head insertion groove 42 is formed (FIG. 16). Next, rail forming grooves 43 are formed on both sides of the head insertion groove 42, and a suspension mounting groove 44 is formed on the back side of the slider material 41 in a direction perpendicular to the rail forming grooves 43. Figure 17).

Once the magnetic head body 14 including the reproducing head section 15 and the slider 13 are constructed, the magnetic head body 14 is inserted into the head insertion groove 42 of the slider 13, as shown in FIG. It is bonded with glass or the like that is fused at high temperature. Subsequently, as shown in FIG. 5, the rail surfaces 45, 45, . . . of the slider 13 are ground and polished, and near the ends of the rail surfaces 45, 45, . disk 8
an inclined surface 4 for introducing air between the slider 13 and the slider 13;
6,46... are formed.

In the above embodiment, the slider 13 and the magnetic head body 14 are constructed separately, but the slider 13 and the substrate 16 of the magnetic head body 14 may be constructed integrally.

〔Effect of the invention〕

As described above, the magnetic head according to the present invention is a magnetic head used for reproducing information recorded in substantially arc-shaped magnetic domains on a recording medium by optically assisted magnetic recording, and includes:
A thin film core formed on a base material and having a magnetic gap portion having a substantially arc shape in the gap width direction corresponding to the shape of the magnetic domain on the recording medium, and a reproduction device provided so as to go around the thin film core. The configuration includes a coil.

According to such a configuration, magnetic flux from magnetic domains on the recording medium is guided from the magnetic gap portion to the magnetic core, and a voltage is induced in the reproduction coil in accordance with a change in the magnitude of this magnetic flux. Therefore, information on the recording medium can be detected based on this voltage, but in this case, since the magnetic gap portion has an almost arc shape corresponding to the shape of the magnetic domain on the recording medium, the information on the recording medium cannot be detected. Crosstalk does not occur between a plurality of adjacent magnetic sections on the medium, and sufficient reproduction signal output can be obtained.

Therefore, in optically assisted magnetic recording, as a result of increasing the recording density, accurate reproduction can be achieved even when the recorded bits form substantially arc-shaped magnetic domains.

Further, the method for manufacturing a magnetic head according to the present invention includes a step of forming a curved portion having a substantially arc shape on the base material by etching, and a thin film having a magnetic gap portion on the base material on which the curved portion is formed. The method includes a step of forming a core, and a step of providing the regeneration coil.

Accordingly, first, the magnetic gap portion is formed on the curved portion of the base material, so that the magnetic gap portion can be formed into a substantially arc shape corresponding to the shape of the magnetic domain on the recording medium.

[Brief explanation of the drawing]

1 to 18 show one embodiment of the present invention. FIG. 1(a) is a schematic plan view of the magnetic head main body. FIGS. 2A and 2B are schematic cross-sectional views taken along line FF in FIG. FIG. 2 is a schematic diagram of a magneto-optical recording/reproducing apparatus equipped with a floating magnetic head. FIG. 3 is a schematic longitudinal sectional view of the disk. FIG. 4 is an explanatory diagram showing the shape of recording bits. FIG. 5 is a perspective view of the floating magnetic head. FIG. 6 is a schematic front view showing the substrate. FIG. 7 is a schematic front view showing how a photoresist film is formed on a substrate. FIG. 8 is a schematic front view showing how etching is performed through a photoresist film. FIG. 9 is a schematic front view showing how the lower thin film core and gap layer are formed. FIG. 10(a) is a schematic plan view showing how the reproduction coil is formed. Figure (b) is a schematic sectional view taken along line A--A in figure (a). FIG. 11 is a schematic vertical cross-sectional view showing how an insulating layer is formed. FIG. 12(a) is a schematic plan view showing how a part of the insulating layer is removed. FIGS. 2A and 2B are schematic cross-sectional views taken along the line BB in FIG. FIG. 13 is a schematic longitudinal sectional view showing how a part of the gap layer is removed. FIG. 14(a) is a schematic plan view showing how the upper thin film core and lead extraction lines are formed. Figure (b) is a schematic front view of the same. Figure (C) is a schematic sectional view taken along line E-E in Figure (a). FIGS. 15 to 17 are schematic perspective views showing the manufacturing steps of the slider, respectively. FIG. 18 is a perspective view showing how the magnetic head body is bonded to the slider. 6 is a recording film (recording medium), 14 is a magnetic head body, 15
17 is a reproducing head portion, 17 is a lower thin film core, 18 is a gap layer (magnetic gap portion), 20 is an upper thin film core, 21 is a reproduction coil, and 26 is a convex portion (curved portion). Patent applicant Sharp Co., Ltd. Figure 10 (a) Figure 10 (b) Figure 11 Figure 12 (a) Figure 12 (b) Figure 13 Figure 14 (a) ) E″″″l Chest 14 Figure (b) Figure 14 (C)

Claims (1)

[Scope of Claims] 1. A magnetic head used for reproducing information recorded in substantially arc-shaped magnetic domains on a recording medium by optically assisted magnetic recording, which is formed on a base material and includes a magnetic head that is formed on a base material and that is connected to the recording medium. It is characterized by comprising a thin film core having a magnetic gap portion having a substantially circular arc shape in the gap width direction corresponding to the shape of the upper magnetic domain, and a reproduction coil provided so as to go around the thin film core. magnetic head. 2. A step of forming a curved portion having a substantially circular arc shape on the base material by etching, a step of forming a thin film core having a magnetic gap portion on the base material on which the curved portion is formed, and the above-mentioned reproduction coil. 2. A method of manufacturing a recording magnetic head according to claim 1, further comprising the step of providing a recording magnetic head.