JPH04114308A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To obtain a thin film magnetic head with a satisfactory reproducing output by providing a dielectric film having a film surface almost parallel to the opposite faces of first and second magnetic cores between both cores. CONSTITUTION:Signal magnetic flux in reproduction tries to flow as shown by a broken line and leakage magnetic flux between the upper and lower magnetic cores tries to flow orthogonally to the film surface of a conductor film 7. Therefore, when the signal magnetic flux is a high frequency, an eddy current flows in the conductor film 7 parallelly to the film surface as shown by a white arrow in the figure, and magnetic flux is generated in a direction to cancel the leakage magnetic flux as shown by a black arrow in the figure. Therefore, the magnetic flux is prevented from leakage between the upper and lower magnetic cores. Generally, the reproducing output of the magnetic head is lowered especially by the high frequency caused by the high frequency loss of a core material or a spacing loss when a medium is slid. Thus, by decreasing the leakage magnetic flux by the high frequency as mentioned above and increasing the reproducing output, the satisfactory head output can be obtained over all the bands.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a thin film magnetic head.

[Conventional technology]

Conventional thin film magnetic heads are described, for example, in the Journal of Applied Magnetics, 13
(1989), pp. 519-524, a pair of thin-film magnetic cores are opposed to each other with a coil, an electrically insulating layer, and a magnetic gap material interposed therebetween, and other components, especially The structure did not include any constituent members made of conductors.

[Problem to be solved by the invention]

Hereinafter, the problems of the above-mentioned conventional thin film magnetic head will be explained with reference to FIG.

FIG. 2(a) is a plan view of a conventional thin film magnetic head.
(b) is a similar side sectional view showing the flow of magnetic flux within the magnetic core. In the figure, 1 is an upper magnetic core, 1' is a lower magnetic core, 2 is a thin film coil, 3 is a magnetic gap, 4 is a medium sliding surface, 5 is a back contact part, 6 is an insulating material between the eyebrows, and 8 is a non-magnetic high Hardness substrate, 9 is a protective film. In FIG. 2(a), the interlayer insulating material 6 and the protective film 9 are omitted to simplify the drawing.

In FIG. 2(b), the broken line indicates the flow of magnetic flux during signal reproduction. The signal magnetic flux from the medium flows into the upper magnetic core 1 from the sliding surface 4, and a portion flows into the lower magnetic core 1' via the magnetic gap 3.

Further, other magnetic flux flows into the lower magnetic core 1' through the bank contact portion 5 so as to circulate around the thin film coil 3.

The magnetic flux that has flowed into the lower magnetic core 1' flows out from the sliding surface 4 again and returns to the medium. In this way, the propagation paths of magnetic flux within the magnetic core are roughly divided into two types, and the larger the amount of magnetic flux that takes the latter path, the higher the regeneration efficiency can be obtained.

However, in the conventional thin-film magnetic head, in addition to the magnetic flux that takes the two routes mentioned above, the magnetic flux passes through the glabella insulating material 6 to the lower core 1'.
There is leakage magnetic flux leading to , and the amount of leakage is large,
The amount of magnetic flux passing through the back contact was small. For this reason, high electromagnetic conversion efficiency could not be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film magnetic head that can reduce leakage magnetic flux and provide good reproduction output.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a conductor film having a film surface substantially parallel to the facing surface between the upper and lower magnetic cores facing each other via a thin film coil.

[Effect]

When the magnetic head according to the present invention is operated at a high frequency, eddy current flows in the conductor film in a direction that cancels out leakage magnetic flux between the upper and lower magnetic cores. Therefore, leakage magnetic flux is reduced, magnetic flux distribution efficiency is improved, and good head reproduction output can be obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1(,) is a schematic plan view showing an embodiment of the thin film magnetic head according to the present invention, and FIG. 1(b) is a similar side sectional view showing the flow of magnetic flux within the magnetic core. In the figure, 1
is the upper magnetic core, 1' is the lower magnetic core, 2 is the thin film coil, 3 is the magnetic gap, 4 is the medium sliding surface, 5 is the back contact part, 6 is the glabella insulation part, 7 is the conductor film, and 8 is nonmagnetic A high hardness substrate, 9 is a protective film. In FIG. 1(,), the glabellar insulating portion 6 and the protective film 9 are omitted to simplify the drawing.

Furthermore, in FIG. 1(b), the broken lines and black arrows indicate the flow of magnetic flux, and the white arrows indicate the flow of eddy current.

The action of the conductor film 7 will be explained in detail below, taking as an example the time of signal reproduction.

In FIG. 1(b), the signal magnetic flux during reproduction flows as shown by the broken line, and the leakage magnetic flux between the upper and lower magnetic cores tends to flow perpendicular to the film surface of the conductor film 7. Therefore, when the signal magnetic flux has a high frequency, an eddy current flows in the conductor film 7 parallel to the film surface as shown by the white arrow, and a magnetic flux shown by the black arrow is generated in the direction of canceling the leakage magnetic flux. This prevents leakage of magnetic flux between the upper and lower magnetic cores. In general, the reproduction output of a magnetic head decreases particularly at high frequencies due to high frequency loss in the core material and spacing loss during sliding of the medium. Therefore, as described above, by reducing leakage magnetic flux at high frequencies and increasing reproduction output, good head output can be obtained over the entire band.

In this embodiment, a rectangular conductor film 7 is provided between the lower magnetic core 1' and the thin film coil 2, in the glabellar insulating part 6. The length of the conductive film 7 in the trunk width direction is larger than that of the magnetic cores 1, 1', and also reduces leakage magnetic flux generated from the side surfaces of the core. Furthermore, by insulating the conductor film 7 from the surroundings, eddy currents are prevented from leaking to the surroundings and the current density is prevented from decreasing.

When the conductor film 7 forms a closed circuit by going around the back contact portion 5, it also obstructs the flow of magnetic flux passing through the gap, reducing regeneration efficiency. In this embodiment, the conductor film 7 is made rectangular to avoid such a problem.

Next, with reference to FIG. 3, a method for manufacturing the thin film magnetic head according to the present invention will be explained by specifically showing an example of materials, film thicknesses, etc. of each part.

First, a groove with a depth of 25 μm having the shape of the lower magnetic core shown in FIG. 1 is formed on the nonmagnetic substrate 8 by photolithography and ion etching. Film thickness 25μ for magnetic core 1'
A CoNbZr film of m thickness is formed by sputtering, and the portions of this film adhering to areas other than the grooves are removed by polishing. Then, a convex portion having a height of 5 μm is formed in a portion corresponding to the magnetic gap forming portion and the back contact portion 5. The film thickness of the interlayer insulating material 6 is 5μ so that the recesses excluding these projections are filled.
A SiC2 film of m thickness is formed by sputtering, and its surface is flattened by polishing to form a lower magnetic core 1'. At this time, the final thickness of the lower magnetic core 1' is 23 μm at the convex portion and 20 μm at the concave portion (FIG. 3(b)).

Next, a Cu film with a thickness of 3 μm is formed on the glabella insulating material 6 by magnetron sputtering, and a conductor film 7 is formed by photolithography (FIG. 3(b)).

Then, a 2 μm thick SiC2 film is formed thereon again, and then a 3 μm thick thin film coil 2 is formed in the same manner as the conductor film 7. Furthermore, a SiO2 film with a thickness of 8 μm is formed on the film using magnetron bias sputtering, and surface irregularities are removed by polishing so that the surface of the film is parallel to the substrate surface (Figure 3 (C)). ).

Next, the SiC2 film on the magnetic gap forming part and the back contact part 5 is removed to form the glabellar insulating part 6 (FIG. 3(d)).

Then, Si with a film thickness of 0.2 μm which becomes the magnetic gap 3
After forming the O2 film, the SiC2 film on the same back contact 5 is removed by etching. On top of that, the film thickness is 20μ
A CoNbZr film of m is formed and processed into a desired shape by ion etching to obtain the upper magnetic core 1. Further, forsterite having a thickness of 60 μm, which will become the protective film 9, is formed by bias magnetron sputtering.

The wafer process is completed with the above steps. All thin film processing during the wafer process uses photolithographic methods and ion milling methods. Also, CoNbZ
The DC facing sputtering method is used to create the r film, and the direction of the plasma convergence magnetic field during film formation is aligned with the track width direction. Furthermore, magnetron sputtering is used to create the 5IO2 film.

After the wafer process is completed, the temperature is set to 460'C, the magnetic field is applied in the track width direction, and the magnetic field strength is 1, 2 x
Heat treatment is performed in a magnetic field for 30 minutes under conditions of 10'A/m2.

After the above heat treatment in a magnetic field, the thin film magnetic head is completed through sliding surface processing, chip processing, and head assembly steps (
Figure 3(e)).

FIG. 4 shows head reproduction outputs of the thin film magnetic head according to the above-described embodiment and the conventional thin film magnetic head.

As is clear from the figure, the thin film magnetic head according to the embodiment has a frequency of 20 M H per frequency compared to the conventional thin film magnetic head.
An improvement of 3 dB was observed in z.

〔Effect of the invention〕

According to the present invention, a thin film magnetic head with good reproduction force can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view (a) and a side sectional view (b) showing an embodiment of a thin film magnetic head according to the present invention, and FIG. 2 is a plan view (a) and a side sectional view (b) of a conventional thin film magnetic head. ), FIG. 3 is a process flowchart showing a specific example of the manufacturing process of the thin film magnetic head according to the present invention, and FIG. 4 shows reproduction output vs. frequency of the thin film magnetic head shown in FIG. 1 and the conventional thin film magnetic head. It is a characteristic diagram. 1... Upper magnetic core, 1'... Lower magnetic core, 2.
・Thin film coil, 3. Magnetic gap, 4. Medium sliding surface, 5. Back contact part, 6. Interlayer insulation part, 7
- Conductor film, 8... Non-magnetic high hardness substrate, 9... Protective film. Atsushi (Kyu) Diagram (cL) Diagram 4 Frequency (MHz)

Claims (1)

[Claims] 1, a first magnetic core, and a second magnetic core are close to each other in the vicinity of the medium sliding surface to form a magnetic gap, and are coupled to each other at a deep part with respect to the medium sliding surface side. a contact portion is formed, the first and second magnetic cores are isolated between the magnetic gap and the back contact portion, and a portion thereof passes between the first and second magnetic cores; In a thin film magnetic head in which a thin film coil is wound around a back contact portion, a conductive film having a film surface substantially parallel to the facing surfaces of both cores is provided between the first and second magnetic cores. Features a thin film magnetic head. 2. A thin film magnetic head according to claim 4, wherein the conductor film is electrically insulated from other head constituent members made of conductors. 3. The thin film magnetic head according to claim 1, wherein the conductor film does not constitute a closed circuit that goes around the magnetic core.