JPS58179927A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To eliminate an element width loss of a thin film magnetic head, by connecting magnetically a permeable matter having contact with a recording medium to an end of the width direction of a magneto-resistance effect element of a ferromagnetic matter and at the same time by connecting magnetically a permeable thin film having contact with the recording medium to the other end of the magneto-resistance effect element with electrical insulation. CONSTITUTION:A cut groove 2 is formed on the surface of an insulated magnetic substrate 1 like ferrite, etc., and a nonmagnetic material 3 is filled into the groove 2. Then an Ni-Fe alloy, for instance, is coated on a new surface finished with the same level as the surface of the substrate 1. Electrodes 5 and 6 are provided at both ends in the lengthwise direction of a magneto-resistance effect element 4, and the element 4 is set in parallel to the lengthwise direction of the groove 2. The upper end part of the element 4 is connected magnetically to the upper end part 10 of the groove 2; while the lower end part of the element 4 is insulated electrically and connected magnetically to the upper end part of a permeable thin film 7 having approximately equal thickness. The signal magnetization recorded on a vertical recording medium 8 is led to the lower part of the element 4 and then to the part 10. Then the signal magnetization passes through the substrate 1 to be led to a contact surface 11 with the medium 8 and then returns to the medium 8. In such a way, the width loss of the element 4 can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to obtain a thin film magnetic head that efficiently internalizes signals recorded in a magnetic medium, and in particular, to reduce the residual magnetization in the direction perpendicular to the running direction of the magnetic recording medium in the running direction, that is, the longitudinal direction. The present invention aims to realize a thin film magnetic head that can read out perpendicularly recorded magnetization signals with high density, which are larger than the residual magnetization in the direction.

It is known that perpendicular magnetic recording is inherently more suitable for high-density recording than conventional longitudinal magnetic recording. but,
There were also various problems during the regeneration process. ? Ii
For example, when reproducing with a wound magnetic head using electromagnetic induction, a single magnetic pole type head or a ring type head is proposed. In the case of reproduction using a ring-shaped head, the gap length must be made extremely small in order to reproduce the short wavelength signal, which is a characteristic of perpendicular recording, and the efficiency of the magnetic circuit of the magnetic head becomes extremely poor. When the number of windings is increased in order to increase reproduction sensitivity, the self-resonant frequency decreases due to an increase in head inductance. On the other hand, as the recording wavelength becomes shorter, the signal frequency becomes higher.

A decrease in the self-resonant frequency of the magnetic head is extremely inconvenient in signal reproduction. In addition, a single magnetic pole type head also has a similar problem because it is a wound type head. An even bigger problem common to electromagnetic induction heads is that when the relative speed between the head and one recording medium is small, the reproduction output voltage is small, about 8 V. The solution to this problem is to increase the number of windings.
Expand the above problem. On the other hand, in a multi-track configuration in which a large number of magnetic heads are arranged in parallel, the space for five windings becomes a problem. 8. When constructed using thin film technology.

The number of windings is limited, making it impossible to create a highly sensitive playback head.

In order to solve these problems, recently the magnetoresistive effect (
(hereinafter abbreviated as MR) heads are attracting attention. A conventional MR head is, for example, a single-element MR head in which a current is passed in the longitudinal direction of a strip-shaped MR element, the MR element is arranged perpendicularly to the recording medium, and a signal magnetic field enters the element plane at right angles to the longitudinal direction.
There is a head.

It is known that in this type of MR head, the wavelength response characteristic caused only by the head structure is determined by the MR element width W. In order to sufficiently reduce this wavelength loss, it is necessary to make W about the wavelength λ, which is extremely disadvantageous for a head oriented to short wavelengths. On the other hand, there is a rolled-type MR head in which a magnetic material with a magnetic permeability of 116 is placed on both sides 11411 of the MR element in the thickness direction. This type of MR
It is known that the head exhibits approximately the same wavelength response as a conventional ring-shaped wire-wound head, and can be used with high sensitivity up to extremely short wavelengths. However, it is necessary to provide magnetic and electrical insulation between the MR element and the high permeability magnetic materials on both sides. Furthermore, since it approximately takes the form of the product of the gap loss of the beam and the gap loss of 92, in order to make the gap loss at short wavelengths sufficiently small, both s ql and q2 should be extremely small. Under this situation, you need magnetic.

It is extremely difficult to form a narrow gap length without electrical leakage.

Furthermore, if the perpendicular recording medium is made of a highly conductive material such as Go-Or, it is necessary to consider electrical leakage between the MR element and the recording medium.

This invention Q solves the conventional problems such as
``Basic configuration is ``City Magnetic Conversion?'' Regarding samurai characteristics, it has no magnetic gap and eliminates loss caused by MRR width.

This is a thin film magnetic head that operates stably even when combined with a conductive recording medium.

That is, the present invention provides an N
MR made of ferromagnetic materials such as Ni-Fe and N1-Go.
One end of a magnetically permeable material in contact with the recording medium is magnetically coupled to one end of the MR element in the width direction, and the other end of the MR element in the width direction is
The structure is such that the magnetically permeable thin film in contact with the recording medium is fully magnetically coupled, and the MR element and the magnetically permeable thin film are electrically insulated.

The present invention will be specifically explained in detail below. 〇 Figures 1 and 2 (2Ll and (bl) show one embodiment of the present invention.

As shown in the figure, an insulating magnetic substrate 1 such as ferrite
A notch groove 2 is provided on the 0 surface, and a non-magnetic material 3 is placed in the notch.
For example, a Ni-Fe alloy is deposited to a thickness of about 500 mm on a new surface that has been filled with and finished flush with the surface of the substrate 1, and an electrode of 5.6 iMR is formed using photolithographic technology.
6% MR elements 4 are arranged at both longitudinal ends of the elements 4 in the longitudinal direction of the notch groove 2 and in the V- row. The upper end of the MRR element 4 is magnetically coupled to the upper end 10 of the notch 2 provided in the magnetic substrate, and the lower end of the MRR element 4 is connected to the upper end of the magnetically permeable thin film 7 of approximately the same thickness. Electrically isolated and magnetically coupled. One specific example of the joint 12 is SiO
2 (2L) shows a structure in which a narrow high magnetic permeability thin film 14 is placed parallel to the MRR element 4 with a thin insulating layer 13 such as SiO2 interposed therebetween. Point 11, which is substantially perpendicular to MRR element 4, is in contact with recording medium 8, and arrow 9 is the direction of movement of the medium.

Another specific example of the joint portion 12 is shown in FIG. 2(b).

After arranging the magnetically permeable thin film 7 in contact with the recording medium 8 parallel to the notch groove 2 and depositing the insulating layer 15 thereon, the MR layer 4
A magnetic thin film is deposited to form a magnetic junction 16 between the two.
Configure. In this case, the order of forming the MRR element 4 and the magnetically permeable thin film 7 may be reversed.

Regarding the substrate material, it does not necessarily have to be a magnetic material substrate as long as it has a structure that efficiently guides the entire signal magnetic flux from the MRR element 4 to the medium 891Q. It may also be one in which a magnetic thin film is adhered to the surface of a magnetic material.

The MR element 4 is often caused to perform linear operation with respect to one signal magnetic field by applying a bias magnetic field HB.

Specific examples thereof are shown in FIGS. 3(2L) and (b). The bias magnetic field 'ff:J-j is obtained by arranging a conductor layer 17 in parallel with the MR element 4 and passing a current through it in the longitudinal direction of the MR element 4. Conductor layer 1
By arranging the high magnetic permeability material 18 in parallel on the side opposite to the 70MR element, the bias efficiency can be increased. Also.

Figure 3 (bl is an auxiliary @ on the opposite side of the head with respect to the medium 8)
I1.19 is placed opposite to the head, and a winding is installed on the auxiliary pole 19 made of a magnetically permeable material, which is magnetized by passing a current or magnetized by a permanent magnet, and the entire bias magnetic field is applied to the MR element 4. It shows.

By configuring the configuration as described below, the perpendicular recording medium 8
The signal magnetization recorded in is guided to the lower end of the magnetically permeable thin film 7 by the thin film magnetic head according to the present invention,
It is guided from the end to the do end of the MR element 4, and from its -4 end to the end 9 of the notch groove 2 in the substrate 1, passes through the substrate, and reaches the contact surface 11 with the medium 8. guided back to medium 8. As a result, element width loss in a single MR head, which has been a problem in the past, is eliminated. By making the thickness of the magnetically permeable thin film 7 approximately the same as that of the MR element 4, a self-generating head without cap loss, which has been a problem in conventional shielded MR heads, can be realized.

8. Furthermore, there is an effect that a single-film magnetic head without the problem of electrical leakage can be realized even when combined with a conductive, self-recording medium.

[Asahi] A complete comparison of the wavelength response characteristics of the magnetic head according to the present invention and a conventional magnetic head is shown in FIG. 4. The horizontal axis shows the reciprocal of the V length λ, that is, the one corresponding to the periodic number, and v1
Relative output on the vertical axis! The 11° single-element type MR head is shown by curve (a), the shield type MR head by curve (b), and the MR head of the present invention by curve (ej). However, the space loss between the head media is not included because the head + is also common.

The structure shown in FIG. 2(a) also has the advantage of minimizing magnetic interference to the MR element 4 during processing of the R film element.

In addition, the magnetic head according to the present invention has the effect of further increasing the electromagnetic conversion efficiency during reproduction by using a two-layer medium or an auxiliary pole with a magnetic permeability layer on the back surface of the medium. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a thin film magnetic head according to an embodiment of the present invention, FIG. 2 (al is a sectional view taken along the line AA' in FIG. FIG. 3 is a cross-sectional view showing a modification of the thin film magnetic head according to the present invention. 1 is a diagram showing a comparison of the wavelength response characteristics of a thin film magnetic head according to the present invention and a conventional magnetic head. 1...Magnetic substrate, 3...Nonmagnetic material, 4
...MR element, 7...Magnetic permeable thin film, 8.
... Recording medium, 17 ... Conductor layer, 19
...Auxiliary electrode, 5.6...Name of electrode 0 representative: R. I, Toshio Nakao, and 1 other person Figure III Figure 2

Claims (2)

[Claims] (1) One end of a magnetically permeable material in contact with a recording medium is magnetically coupled to one end in the width direction of a magnetoresistive element made of a ferromagnetic material having electrodes at both ends, and the other end in the width direction of the magnetoresistive element is A thin film magnetic head, characterized in that a magnetically permeable thin film in contact with the recording medium is magnetically coupled, and the magnetoresistive element and the magnetically permeable thin film are electrically insulated. (2) Thin film magnetism according to claim 1, characterized in that the magnetoresistive element and the magnetically permeable thin film have approximately the same thickness and are magnetically coupled by a magnetically permeable material via a non-conductive material. head.