JPH01296421A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To prevent the generation of the fluctuation in the base line of a reproduced output waveform and to improve recording and reproducing characteristics by lowering the height of a magneto-resistance effect element disposed between front end parts of two magnetic pole layers to the depth lower than the depth of the gap sandwiched directly by said ends. CONSTITUTION:The magneto-resistance effect element 31 which is laminated successively with the magnetic pole layer 12, a thin film coil 15 sandwiched by a gap layer 13 and an interlayer insulating layer 14, the 2nd magnetic pole layer 16, and a protective layer 17 and has the depth L of the gap depth Dg or below in the layer 13 is disposed on a nonmagnetic substrate 11. The 1st and 2nd magnetic pole layers 12, 16, therefore, function completely as a shielding magnetic material at the time of reproduction in the same manner as a shielded type material MR head in the constitution enclosing the element 31, by which the generation of the fluctuation in the base line of the reproduced output waveform is prevented and the problems such as increased waveform distortion and degraded recording density characteristic are solved.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a thin film magnetic head for recording and reproduction incorporating a magnetoresistive element for reproduction used in a magnetic disk device, a magnetic tape device, etc. Gap depth og in the gap layer directly sandwiched between the pole tips of the two magnetic pole layers and M in the gap layer
By optimizing the relationship with the height L of the R element, we aim to prevent baseline fluctuations in the reproduced output waveform and improve the recording/reproducing characteristics. A thin film magnetic head comprising a nonmagnetic gap layer and a thin film coil disposed between magnetic pole layers, and a flat magnetoresistive element in the gap layer, the magnetoresistive element in the gap layer having a flat magnetoresistive effect element. The element height is set to be lower than the gap depth in the gap layer directly sandwiched between the tips of the first and second magnetic pole layers.

[Industrial Field of Application] The present invention relates to a thin film magnetic head used in a magnetic disk device, a magnetic tape device, etc., and particularly relates to a thin film magnetic head for recording and reproducing in which a magnetoresistive element for reproducing is incorporated. It is something.

Thin-film magnetic heads for recording and reproducing which integrally constitute an inductive magnetic head for recording and a magnetoresistive element for reproducing are disclosed in JP-A-59-30223 and JP-A-61-1.
It has already been proposed in Japanese Patent Application No. 94620, etc., and since the reproduction output does not depend on the medium speed and a relatively large output can be obtained, it is extremely advantageous for information reproduction of high-recording trunks. This head is expected to replace inductive magnetic heads.

In a magnetic head having such a configuration, baseline fluctuations (Heasline shift) tend to occur in the reproduced output waveform, and as a result, recording density characteristics tend to deteriorate.

Therefore, there is a need for a head configuration that eliminates such inconveniences.

[Prior Art] A conventional recording/reproducing thin film magnetic head incorporating a magnetoresistive element (hereinafter referred to as MR element) for reproduction uses, for example, a non-magnetic [Substrate] A first magnetic pole layer 12, a gap layer 13, and an interlayer insulating layer 14 on the substrate]
A thin film coil 15, a second magnetic pole layer 16, and a protective layer 1 sandwiched between
7 are stacked in order, and an MR element 18 is disposed within the gap layer 13.

The tips of the first magnetic pole layer 12, the second magnetic pole layer 16, and the MR element 18, which directly face each other with the MR element 18 and the gap layer 13 in between, are placed on the surface of the substrate 11 on which the second magnetic pole layer 12 is disposed. This surface is exposed on a surface perpendicular to the magnetic recording medium 20, and this surface is a so-called medium facing surface 19 that faces the magnetic recording medium 20.

And the first and second magnetic pole layers 12.16 and the thin film coil 15
Writing and reading of information to and from the opposing magnetic recording medium 20 are shared by the MR element 18 in which the -1st second magnetic pole layer 12.degree. 16 is made of a shielding magnetic material.

[Problem to be solved by the invention]

By the way, in the conventional thin film magnetic head for recording and reproducing having the above-mentioned configuration, a base line fluctuation (Haesline shift) occurs in the reproduction output waveform when information is reproduced from the opposing magnetic recording medium 20, and as a result, the waveform This method has drawbacks such as an increase in distortion and a decrease in recording density characteristics.

Such a drawback is related to the shape of the magnetic pole tips of the first and second magnetic pole layers 12.16 near the center of the gap layer 13 and the height of the MR element 18. That is, as shown in FIG. When the height L of the MR element 18 is large, as shown in the fourth enlarged view, magnetic flux flows from the magnetic recording medium 20 to the tip of the MR element 1B during reproduction, and at the same time, for example, the second magnetic pole layer 16 Originally, the magnetic flux 21 flowing into the tip of the magnetic pole layer 12 should return to the medium side via the first magnetic pole layer 12, but as shown by the arrow, the space between the first and second magnetic pole layers 12°16 has become wider. Since the magnetic flux 21 flows through the rear part of the MR element 18 in the region where the magnetic flux 21 flows to the first magnetic pole layer 12, the base line fluctuation of the reproduced output waveform is caused by the magnetic flux 21 flowing through the MR element 18.

In Figure 5, the gap depth Dg is 2 μm and the height L of the MR element.
This figure shows an example of a reproduction output waveform obtained by computer simulation of a conventional thin-film magnetic head for recording and reproduction when 5 μm, and it can be seen that a very large baseline fluctuation appears. The figure also shows responses to two magnetization reversals with different polarities.

In view of the above-mentioned conventional drawbacks, the present invention provides a relationship between the gap depth Dg in the gap layer directly sandwiched between the first magnetic pole layer and the second magnetic pole tip and the height L of the MR element in the gap layer. The object of the present invention is to provide a novel carbon dioxide magnetic head which prevents the occurrence of baseline fluctuations in the reproduced output waveform and improves the reproduction characteristics by optimizing the reproduction characteristics.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a non-magnetic gap layer and a thin film coil disposed between a first magnetic pole layer and a second magnetic pole layer, and a flat magnetoresistive element in the gap layer. 6. A thin film magnetic head having a structure in which the element height L of the MR element in the gap layer is lower than the gap depth ng in the gap layer directly sandwiched between the tips of the first and second magnetic pole layers. shall be.

(Function) In the thin film magnetic head 27 of the present invention, an MR layer with an element height lower than the gap depth is provided in the gear layer directly sandwiched between the first magnetic pole layer and the first magnetic pole layer magnetic pole tip. Since the element Y- is provided, the configuration surrounding the MR element during reproduction is similar to that of the known shielded MR element, and the first,
Second, the magnetic pole layer fully functions as the sole I magnetic material. As a result, the occurrence of fluctuations in the reproduced output waveform is prevented.

[Example] Hereinafter, an example of the present invention will be described in detail using the -1V plane.

1 is a cross-sectional view of a main part showing an embodiment of a thin film magnetic head for recording and reproducing according to the invention, and the same parts as in FIG. 3 are given the same reference numerals.

In this embodiment, for example, a first magnetic pole layer 12, a gap layer 13, a thin film coil 15 sandwiched between an interlayer insulating layer 14, a second magnetic pole layer 16, and a protective layer 17 are laminated in this order on a nonmagnetic substrate 11. In the gap layer 13 having a structure,
A short MR element 31 having a height L that is less than the gap depth t)g is disposed.

Therefore, the structure surrounding the MR element 31 is the same as that of the known shield type MR element I.
The MR element 31 is configured to function completely as a shielding magnetic material during reproduction, and the MR element 31 does not serve as a path for the magnetic flux 21 flowing into the first magnetic pole layer 12 from the second magnetic pole layer 16 as in the conventional case, so that the reproduction output is reduced. The occurrence of baseline fluctuations in the waveform is prevented, and problems such as increased waveform distortion and decreased recording density characteristics are resolved.

FIG. 2 shows an example of the reproduction output waveform of the thin film magnetic head for recording and reproduction of the present invention based on computer simulation. For example, while the gap depth Dg is 7 μm, the height of the MR element 31 is When L was set to 5 μm, baseline fluctuations in the reproduced output waveform could be easily eliminated and confirmed.

[Effects of the Invention] As is clear from the above description, the thin-film magnetic head according to the present invention has an excellent advantage in that the occurrence of baseline fluctuations in the reproduced output waveform is easily eliminated, and the reproduction characteristics are significantly improved. It has great practical effects such as improved performance, and is extremely advantageous when applied to this type of thin film magnetic head for recording and reproducing.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part showing an embodiment of a thin film magnetic head according to a civil engineering invention, Fig. 2 is a diagram for explaining the reproduction output waveform of the thin film magnetic head according to the invention, and Fig. 3 is a conventional diagram. 4 is a partially enlarged cross-sectional view showing the vicinity of the gap of a conventional thin-film magnetic vent, and FIG. 5 is a baseline of the reproduction output waveform of the conventional thin-film magnetic head. This is M for explaining the fluctuation. In FIG. 1, 11 is a nonmagnetic substrate, 12 is a first magnetic pole layer, 3 is a gap layer, 14 is an interlayer insulating layer, 15 is a thin film coil, 16 is a second magnetic pole layer, 17 is a protective layer, and 31 is an MR. The elements are shown respectively. 110- -K, 0-150-10.0-5.0 0.0 5,0
Figure 2 Figure 4

Claims (1)

[Claims] A nonmagnetic gap layer (13) and a thin film coil (15) are arranged between the first magnetic pole layer (12) and the second magnetic pole layer (16),
and a thin film magnetic head having a flat magnetoresistive element (31) in the gap layer (13), wherein the element height of the magnetoresistive element (31) in the gap layer (13) is , a thin film magnetic head characterized in that the gap depth is lower than that in a gap layer (13) directly sandwiched between the tips of the first and second magnetic pole layers (12, 16).