JPS5971122A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To reproduce the short wavelength signal magnetization being a characteristic of the vertical magnetic recording efficiently and stably, by eliminating the ruggedness on the recording medium running surface, in an MR head for vertical magnetization signal reproduction without width loss, and thickness loss corresponding to gap loss. CONSTITUTION:A groove 2 having a depth being the sum of a desired groove depth (about 5mum) and an abrasion margin (about 5mum) is formed by polishing the surface of an insulating base 1 such as ferrite and applying electrolytic etching. Then, a nonmagnetic member 3 such as SiO is formed into a thickness over the depth of the groove 2. Further, the surface is polished and Ni-Fe alloy, e.g., is vapor-deposited by about 500Angstrom on the surface having the same mating plate of the ferrite base 1 with the SiO plane of the groove 2 and having a desired groove depth, electrodes 5, 6 are arranged at both ends in lengthwise direction of the MR element by photo etching, the MR element 4 is provided in parallel with the lengthwise direction of the notch groove 2, and an SiO protection film is formed into a thickness >=10mum by vapor-deposition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thin film magnetic head suitable for reproducing perpendicular magnetization.

Conventional Structures and Problems Perpendicular magnetic recording is known to be inherently more suitable for high-density recording than conventional longitudinal magnetic recording. However, there were still many problems during the regeneration process. for example,
When playing with a wound magnetic head using electromagnetic induction,
Single magnetic pole heads and ring heads have been 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 in this case, 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, since the signal frequency becomes higher as the recording wavelength becomes shorter, a decrease in the self-resonant frequency of the magnetic head is extremely inconvenient in signal reproduction. Also, since the 3L-knee single-pole head has a wound type head, a larger problem common to the 0 electromagnetic induction head, which has similar problems, is that when the relative speed between the head and the recording medium is small, The reproduced output voltage becomes smaller, and the countermeasure is to increase the number of windings, which increases the above problem. On the other hand, in a multi-track configuration in which many magnetic heads are arranged in parallel,
Furthermore, when using thin film technology, the number of windings is limited and a highly sensitive reproducing head cannot be realized.

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. In this type of MR head, it is known that 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, the element width W must be set to approximately the wavelength λ. This is extremely disadvantageous for short-wavelength oriented RAD. On the other hand, there is a shield type MR head in which a magnetic material with high magnetic permeability is arranged on both sides of the MR element in the thickness direction. It is known that this type of Ml'L head exhibits substantially the same wavelength response as a conventional ring-shaped wire-wound head, and can be used with high sensitivity up to considerably 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, and the insulation layer thickness q1 + 92 between them is equal to the gap length of the conventional ring-shaped wire-wound head. Equivalent to.

Furthermore, since the approximate form is the product of the gap loss of ql and the gap loss of 92, in order to make the gap loss at short wavelengths sufficiently small, ql.

Both q2 must be extremely small, and under this situation it is extremely difficult to form a narrow gap length free from magnetic and electrical leakage.

In order to solve the above-mentioned problems, the present inventors proposed the following thin film head in Japanese Patent Application No. 57-627.
No. 31). That is, in the thin film head, one end in the width direction of an MR element made of a ferromagnetic 5-non material such as Ni-Fe or N-Co, which has electrodes at both ends, faces the recording medium, and the other end faces the recording medium. A thin-film head with a structure in which one end of a magnetically permeable material in contact with the recording medium is magnetically coupled, and it does not have a magnetic gap that greatly affects electromagnetic conversion characteristics in high-density recording areas.
A feature is that width loss caused by the MR element width is eliminated. To explain specifically using the drawings, as shown in FIGS. 1 and 2, a notch groove 2 is provided on the surface of an insulating magnetic substrate 1 such as ferrite, and a non-magnetic material 3 is placed in the notch. For example, 55% of Ni-Fe alloy is deposited on the new surface which is filled with Ni-Fe alloy and finished in the same manner as the surface of the substrate 1.
The electrode 6 is deposited to a thickness of about 0'O,
6 are arranged at both ends of the MR element 4 in the longitudinal direction, and the MR element 4
are provided parallel to the longitudinal direction of the notch groove 2. After that, M.R.
In order to protect the element, a protective film or protective substrate 13 (first
(not shown in the figure). The upper end of the MR element 4 is magnetically coupled to the upper end 9 of the notch 2 provided in the magnetic substrate 1, and the lower end of the MR element 4 is in contact with the recording medium 7. A surface 1o of the magnetic substrate 1 that is approximately perpendicular to the MR element 4 is the surface that comes into contact with the recording medium 7, and an arrow 8 is the direction of movement of the medium. Note that the dimension of the notch groove in the medium movement direction is large enough that it does not act as a gap in the ring head, and although it varies depending on the signal wavelength handled, it is about 5 μm.
It is desirable that there be more than that.

The above MR head uses base 1 as a recording medium.
By using a perpendicular two-layer film medium in which a soft magnetic layer 11 is interposed between the perpendicularly magnetized film 7 and the perpendicularly magnetized film 7, high performance characteristics can be achieved. That is, the magnetic flux generated from the signal magnetization recorded on the perpendicular recording medium 7 is guided from the lower end of the MR element 4, and
It passes through the element 4, is guided from its upper end to the end 9 of the notch groove 2 in the substrate 1, is guided through the substrate 1 to the contact surface 1° with the medium 7, and returns to the medium 7, and the soft magnetic A closed magnetic path configuration is formed through the layer 11 and back to the lower end of the MR element 4.

On the other hand, metal-deposited tapes have recently been actively developed as magnetic recording media, but when such conductive recording media are used, the Ml (a structure in which the MR element contacts the medium like a head) In this case, the problem of electrical leakage occurs.Even in such a case, the inventor has developed an MR head as shown in Fig. 3 as a usable head.
The head was proposed (Japanese Patent Application No. 57-62728) 0. That is, the basic structure and operating principle are the same as the previously proposed MR head, but the MR element 4 is placed away from the medium, and one end is connected to the recording medium 7. In this configuration, a magnetically permeable thin film 14 is disposed, which faces the MR element 4 and whose other end is magnetically coupled to the MR element 4 and at the same time electrically insulated from the MR element 4. FIG. 4 shows another embodiment, in which an insulating thin film 15 made of a non-magnetic material is disposed between the MR element 4 and the magnetically permeable thin film 14.

The MR head proposed above is a magnetic head suitable for reproducing perpendicular magnetization, but in any case, the non-magnetic material to be filled into the notch groove 3 during manufacture is glass with a relatively low melting point suitable for the filling operation. was used, and the protective film 13 was formed thickly by vapor deposition of SiO or the like so as to be in close contact with the thin film portion. When a recording medium runs on the head surface with such a configuration, large irregularities occur due to uneven wear as shown in FIG. It protruded by about 1 to 0.2 μm, resulting in a large space loss when reproducing short wavelength signals, which is a characteristic of perpendicular magnetic recording, and the high-density characteristics of the MR head could not be fully exploited.

Purpose of the Invention As described above, the present invention is an MR head for perpendicular magnetization signal reproducing without width loss or thickness loss corresponding to gap loss, which eliminates unevenness on the running surface of a recording medium and achieves a short wavelength characteristic of perpendicular magnetic recording. The object of the present invention is to provide a thin film magnetic head that efficiently and stably reproduces signal magnetization.

Structure of the Invention In order to achieve the above object, the present invention is characterized by being structured by the following members.

(a) A group of magnetically permeable thin films including at least an MR element with one end facing the recording medium side.

(b) A magnetically permeable body having one end disposed near the recording medium and the other end magnetically coupled to the MR element.

(C) a nonmagnetic material disposed at least in the vicinity facing the recording medium between the magnetically permeable thin film group and the magnetically permeable material; (d) a 91° di-nonmagnetic material having a Vickers hardness approximately equal to that of the nonmagnetic material; A magnetically permeable thin film protective member made of material.

According to the present invention, by forming a closed magnetic circuit configuration and reproducing signal magnetization recorded on a perpendicular recording medium with the configuration of members a, b, and c, there is no thickness loss corresponding to width loss or gap loss. Furthermore, by introducing member d, the Vickers hardness of the non-magnetic material on both sides of the magnetically permeable thin film group is made equal, thereby eliminating uneven wear and eliminating space loss due to unevenness on the recording medium running surface near the magnetically permeable thin film group. Therefore, short wavelength signals can be regenerated with high efficiency.

Although the explanation structure of the embodiment is the same as that shown in FIGS. 1 to 4, it will be explained here using FIGS. 1 and 2.

After polishing the surface of an insulating substrate 1 such as ferrite, the portions except the grooves are covered with photoresist using photolithography, and then the desired groove depth of about 6μ is formed using electrolytic etching.
A groove with a depth equal to m) plus the polishing method (approximately 6 μm) is formed. 7 After removing the photoresist, 5ill of non-magnetic material 3 is formed to have a thickness at least equal to or greater than the depth of the groove 1o. After that, the surface is polished so that the surface 5i03 of the groove 2 and the surface of the ferrite substrate 1 are on the same plane and the desired groove depth is formed.For example, Ni-Fe alloy is deposited by 500 people using a vapor deposition method on the surface. Electrodes 5 and 6 are arranged at both ends of the MR element 4 in the longitudinal direction by photolithography, and the MR element 4 is provided parallel to the longitudinal direction of the notched groove 2.

After that, in order to protect the MR element, a Si protective film 1 is applied by vapor deposition.
3 with a thickness of 10 μm or more.

The MR head fabricated in this way efficiently reproduces high-density perpendicular magnetization with a submicron bit length through the operation described above, and even when the recording medium runs, the non-magnetic magnetization on both sides of the magnetically permeable thin film group Because they are made of the same material, irregularities occur near the magnetically permeable thin film group due to uneven wear, but because the tip of the magnetically permeable thin film group on the recording medium side is always in stable contact with the recording medium, as shown in the conventional example. There is no large short-wavelength loss, and extremely high-resolution reproduction characteristics can be obtained.

Further, as described above, ferrite is used as the magnetically permeable substrate, and a material having a Vickers hardness equal to or higher than that of the ferrite material, such as 11'-SiO, is arranged as a nonmagnetic material on both sides of the magnetically permeable thin film group. As a result, in addition to the above-mentioned advantages, a thin film magnetic head with extremely excellent wear resistance can be obtained.

A comparison of the wavelength response characteristics of the magnetic head according to the present invention and a conventional magnetic head is shown in FIG. The horizontal axis is the reciprocal of the wavelength λ, that is, the one that corresponds to the frequency, and the vertical axis is the relative output.The single-element MR head is curve A.
The shield type MR head is shown by ``1'', the previously proposed MR head in which the Vickers hardness of the non-magnetic material on both sides of the magnetically permeable thin film group is greatly different is shown by ``c'', and the MR head according to the present invention is shown by ``2''. However, in this case, the space loss between the head and the medium is not included because it is common to all heads.

Effects of the Invention As described above, the thin-film magnetic head of the present invention has no thickness loss equivalent to width loss or gap loss, and also minimizes space loss due to unevenness on the head surface, and can efficiently generate high-sensitivity perpendicular magnetization signals. Can be played.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a thin film magnetic head, and Figure 2 is A of Figure 1.
3 is a perspective view of another thin film magnetic head, FIG. 4 is a sectional view showing another embodiment of the main part of the same head shown in FIG. 3, and FIG. 5 is a sectional view taken along line A'. FIG. 6 is a diagram showing the surface shape of the recording medium running surface of a conventional thin-film magnetic head, and FIG. 6 is a diagram showing a comparison of the wavelength response characteristics of the conventional example and the magnetic head according to the present invention. 1...Magnetic permeable material, 3...Nonmagnetic material, 4
...MR element, 7...Recording medium, 13
...Protective member, 14... Magnetically permeable thin film. Name of agent: Patent attorney Toshio Nakao and one other person
＼＼ Figure 3 Figure 5 Figure 6 0, f / 10 - (shi Δ) / 1L7L Go

Claims (3)

[Claims] (1) One end of the magnetically permeable thin film including the magnetoresistive element faces the recording medium, the other end is magnetically coupled to a magnetically permeable body, and one end of the magnetically permeable body is placed near the recording medium. ,and,
A thin film magnetic head comprising a non-magnetic material on both sides of the magnetically permeable thin film at least in the vicinity of the surface facing the recording medium, and wherein the non-magnetic materials on both sides of the magnetically permeable thin film valve are made of materials having substantially equal hardness. . (2) The thin film magnetic head according to claim 1, wherein the nonmagnetic materials on both sides of the magnetically permeable thin film are made of the same material. (3) The magnetically permeable body is not a ferrite material, and the magnetically permeable thin film is provided with a non-magnetic material having a hardness comparable to or higher than that of the ferrite material on both sides of the magnetically permeable thin film.
Thin film magnetic head according to item 0 or 2