JPS607608A - thin film magnetic head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thin film magnetic head that efficiently reproduces magnetization signals perpendicularly recorded in a perpendicular magnetic recording medium.

Conventional configurations and their problems It is known that perpendicular magnetic recording is inherently more suitable for high-density recording than conventional longitudinal magnetic recording.However, there are still various problems in the reproduction process. For example, when reproducing with a wound magnetic head using electromagnetic induction, a single magnetic pole type head or a ring type head is used as a subsidiary system. When reproducing with a ring-shaped head, the gap length must be extremely small in order to reproduce short wavelength signals, which are 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, since the signal frequency increases as the recording wavelength becomes shorter, 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. A more serious problem common to electromagnetic induction heads is that when the relative speed between the head and the recording medium is small, the reproduction output voltage becomes small, and the solution to this problem is to increase the number of windings, which aggravates 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 winding space becomes a problem.Furthermore, in the case of a configuration using thin film technology, the number of windings is limited, making it impossible to realize a highly sensitive read head.

In order to solve these problems, 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, W needs to be about the wavelength λ, which is extremely disadvantageous for heads oriented to short wavelengths. 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 well known that this type of MR head has almost the same wavelength response as a conventional ring-shaped wire-wound head and can be used with high sensitivity at considerably short wavelengths.
However, it is necessary to provide magnetic and electrical insulation between the MR element and the high permeability magnetic layers on both sides, and the thickness of the insulator layer between them is V1. (J2 corresponds to the gear length of the conventional ring-shaped winding head.

Furthermore, since approximately the gap loss is in the form of a gap loss of q and a gap loss of 92, in order to make the gap loss at short wavelength sufficiently small, ql.

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

Purpose of the Invention As described above, the present invention substantially does not have a magnetic gap that greatly affects electromagnetic conversion characteristics, and eliminates width loss caused by the MR element width, thereby achieving high reproduction in high-density recording areas. It is efficient and easy to manufacture using thin film technology.
An object of the present invention is to provide a stable thin-film magnetic head with less variation.Structure of the InventionThe present invention provides a magnetoresistive element made of a ferromagnetic material having electrodes at both ends on a non-magnetic substrate. A first non-magnetic thin film made of an electrical insulator is formed on the magnetoresistive element and the electrode, a second non-magnetic thin film having a large film thickness is further formed on the magnetoresistive element, and the A high magnetic permeability ferromagnetic layer is formed in the first layer so that the magnetoresistive element is magnetically coupled through the first nonmagnetic thin film. This is a thin film magnetic head formed on a second nonmagnetic thin film. According to this thin film magnetic head, magnetic flux generated by signal magnetization recorded on a perpendicular recording medium is guided to the MR element from the lower end of the magnetoresistive element (MR element).

Since it returns to the medium from its upper end through the high permeability ferromagnetic layer, there is no MR element width loss in a single-piece MR head and no gear knob loss in a shielded MR head. or,
In order to construct an MR element directly on a non-magnetic substrate,
There is little variation in characteristics, and stable high-density perpendicular magnetization reproduction can be performed.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. As shown in Figs. 1 and 2, a ferromagnetic thin film of Ni-Fe, Ni-C0, etc. is deposited on a non-magnetic substrate 1 of SiO2 or 82203 using a method such as vapor deposition or spatter. The MR element 2 is formed by photolithography. Furthermore, Au and A, which become the electrodes of the MR element 2,
A conductor such as fl or Cu is deposited using a method such as vapor deposition or sputtering, and a desired pattern (conductor layer) 3 is formed by photolithography. A first non-magnetic thin film 4 such as SiO is placed thereon to insulate a part of the conductive layer 3 and the MR element 2 from the upper magnetic layer 5, and furthermore, the upper ends of the M and R elements are A second film with a large thickness such as SiO is placed on the removed part.
The nonmagnetic thin film 6 is formed into a desired shape with a thickness of about 5 to 100 μm using a lift-off technique.

Furthermore, a ferromagnetic layer 5 such as Ni--Fe is deposited by a method such as vapor deposition or sputtering, and is arranged so as to be magnetically coupled to the two ends of the MR element.

In order to protect the reproducing head from wear due to the running of the recording medium 7, a cover member 2 is attached with an adhesive 20 such as glass or resin.
Glue 1. The upper end of the MR element 2 is magnetically coupled to the ferromagnetic layer 5, and the lower end is in contact with the recording medium 7. A surface 8 on the non-magnetic substrate 1 that is substantially perpendicular to the MR element 2 is a surface that comes into contact with the recording medium 7, and an arrow 9 indicates the direction of movement of the medium.As a result, a signal generated from the signal magnetization recorded on the perpendicular recording medium 7 The magnetic flux is led from the lower end of the MR element 2,
The light passes from the upper end of the MR element, passes through the magnetic layer 5, returns to the medium through the contact surface 8 with the medium 7.

As another embodiment, the non-magnetic thick film 6 has terminals at both ends.
The MR element can be biased by passing a current through the conductor 6 □ Also, on the part of the non-magnetic substrate 1 where the MR element 2 is formed, a certain period of time is applied. By providing a lattice-like unevenness with a lattice-like unevenness and arranging the lattice-like unevenness so that the direction of the lattice-like unevenness is inclined with respect to the longitudinal direction of the MR element 2, an anisotropic magnetic field that maintains the direction of easy magnetization of the MR element at an angle with the current direction of the element is generated. By appropriately setting the slope, operation with less second harmonic distortion can be achieved. Since the MR element can be directly formed thereon, a thin film head that performs stable bias operation with little variation can be obtained.

Effects of the Invention As described above, according to the present invention, there is no MR element width loss in single-piece MR heads, which has been a problem in the past, and there is no gap loss seen in conventional magnetic heads. A magnetized reproducing head can be realized. moreover,
It is easy to manufacture a non-magnetic substrate using a non-magnetic substrate, and since the MR element is directly attached to the non-magnetic substrate, there are no steps on the MR element, and the magnetic anisotropy created in the longitudinal direction of the MR element is not visible. This has the advantage that a reproducing head with uniform MR characteristics can be obtained without any distortion.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a section of a part of a thin film magnetic head in an embodiment of the present invention, and FIG. 2 is an A in FIG. 1.
-IV line sectional view. 1... Nonmagnetic substrate, 2... Magnetoresistive element, 3... Conductor, 4, 6... Insulator, 5... Magnetic material, 7...Recording medium, 8
... Media running surface, 9... Media running direction, 20... Adhesive, 21... Cover glass 0 Name of agent Patent attorney Satoshi Nakao Male and 1 other person 43
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Claims (1)

[Claims] (1) A magnetoresistive element made of a ferromagnetic material having electrodes at both ends is provided on a non-magnetic substrate, and a first non-magnetic thin film made of an electrical insulator is placed on the magnetoresistive element and the electrodes. A second non-magnetic thin film with a large thickness is formed on the magnetoresistive element A, and a highly permeable film is formed so that the magnetoresistive element is magnetically coupled via the first non-magnetic thin film. Magnetic property ferromagnetic material layer is the above-mentioned No. 1. A thin film magnetic head formed on the second nonmagnetic thin film. ? ) The thin film magnetic head according to claim 1, wherein the second nonmagnetic thick film is made of a conductor having terminals at both ends, and a current is caused to flow through the conductor (3) On a nonmagnetic substrate At least in the part where the magnetoresistive element is formed,
2. A thin-film magnetic head according to claim 1, wherein the lattice-like uneven grooves having a period of - are provided to be inclined with respect to the current direction of the magnetoresistive element.