JPH02172010A - Composite type thin-film magnetic head - Google Patents

Abstract

PURPOSE:To efficiently generate magnetic fields by setting magnetostriction of a magnetic film forming the magnetic poles of the magnetic head positive. CONSTITUTION:Shielding patterns 2 tapered at the end are formed on a substrate 1. A magneto-resistance effect element 4 is then inserted and formed between insulating layers 3. A lower magnetic pole 5 and an insulating layer 6 to constitute a gap layer are laminated. Conductor coil patterns 7 and a flatting layer 61 are then formed. The layer 61 is taper-etched to form tapered parts, then an upper magnetic pole 8 and a protective film 9 are formed. An Ni-Fe alloy is used for the upper and lower magnetic poles 8, 5 and the magnetostriction thereof is set at the positive value by regulating the compsn. The optimum recording current value is low and the recording efficiency is high when the magnetostriction is positive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a composite type thin film magnetic head, and more particularly to a composite type thin film magnetic head in which recording and reproduction are separated and is suitable for high-density magnetic recording.

(Prior Art) In order to increase the density of magnetic recording, a composite thin-film magnetic head with separate recording and reproducing functions has been proposed.The structure of the composite thin-film magnetic head uses a magnetoresistive element. A structure in which an inductive thin film magnetic head is stacked on top of a read head is known.

It has a laminated structure as shown in Figure 3.

A shield layer 2 of a magnetoresistive element is placed on a nonmagnetic substrate 1,
Subsequently, a magnetoresistive element 4 made of a Ni--Fe alloy is laminated via an insulator M3. moreover.

A shield Jl/lower magnetic pole layer 5 is laminated via an insulating layer 3, and a conductor coil 7 is formed in the insulating layer 6.

Finally, the upper magnetic pole 8 and the protective film 9 are laminated to form a composite thin film magnetic head.

In such a composite thin film magnetic head, an inductive thin film magnetic head records on a medium, and a magnetoresistive element reads signals written on the medium.

Regarding the film head with such a structure, Japanese Patent Application Laid-Open No. 1986-
93127 and I, E, E, E Transactions on Magnetics.

M.N.G. 17 (1,981), pp. 2890-2892 (IEEE Trans, Magna
tics, MAG17 (1981) pp.

2890-2892).

By the way, as described in Japanese Unexamined Patent Application Publication No. 55-101124, the magnetic pole of an inductive thin film magnetic head used alone has been coated with a magnetostrictive negative magnetic film from the viewpoint of reproduction efficiency and noise reduction during reproduction. was used. Also in the composite magnetic head, in the induction type thin rIA magnetic head for recording, the magnetostriction of the magnetic pole magnetic film is made negative. The composite thin-film magnetic head has separate recording and reproducing functions, and has the advantage that even if the pole thickness of the recording-only inductive thin-film magnetic head is increased to increase the recording capacity, the reproducing resolution will not deteriorate. Therefore, the pole thickness of the recording-only induction type 411g magnetic head, that is, the thickness of the pole magnetic film, has been increased. However, there was a problem in that the recording efficiency was extremely degraded.

Problem to be Solved by the Invention 1 The above conventional technology has problems in efficiently generating a recording magnetic field because sufficient consideration has not been given to the magnetostriction of the magnetic pole magnetic film of the inductive head, that is, the recording head. was there. An object of the present invention is to provide a composite thin film magnetic head that can efficiently generate a magnetic field.

(Means for Solving the Problems) The above object can be achieved by making the magnetostriction of the magnetic pole magnetic film of the inductive thin film magnetic head, that is, the recording head positive.

(Function) When the magnetostriction of the pole magnetic film is negative, as the thickness of the magnetic film increases, magnetic anisotropy perpendicular to the film surface is induced.

For this reason, it is difficult to magnetize in the in-plane direction, and sufficient magnetic flux cannot be emitted from the tip of the magnetic pole, which is thought to be the reason why the recording efficiency of thin-film recording heads with this magnetic film at the magnetic pole is reduced. The cause of this perpendicular anisotropy is considered to be the inverse magnetostriction effect caused by the interaction of the internal stress present in the film and the magnetostriction of the magnetic film. Therefore, it is considered that making the magnetostriction of the pole magnetic film positive has the effect of suppressing the induction of perpendicular magnetic anisotropy in the pole magnetic film, thereby preventing deterioration of recording efficiency.

(Example] An embodiment of the present invention will be described below.

A composite thin film magnetic head whose cross-sectional view is shown in FIG. 3 was fabricated.

A shield pattern 2 with tapered ends is formed on the substrate 1.
form. Subsequently, the magnetoresistive element 4 is formed with the IIA edge layer 3 sandwiched therebetween. Next, lower magnetic pole 5. An insulating layer 6 serving as a gap layer is laminated, and then a conductive coil pattern 7 and a flattened layer M61 are formed. Thereafter, the flattening layer is taper-etched to form a tapered portion, and the upper magnetic pole 8 is
and a protective film 9 is formed.

Here, the substrate l is a zirconia substrate with A1□0.
A material coated with was used. The shield layer was made of a Ni-Fe alloy, and had a thickness of 1.0 pm and a height of 10 μm. Taper etching of the shield layer was performed by ion milling using a photoresist with a tapered cross section as a mask.

The bias method in the magnetoresistive element 4 is a shunt bias method, and a Ni-Fe alloy with a film thickness of 45 nm and a film thickness of 2
00 nm Mo films were stacked, and the height thereof was 5 μm.

The insulating layer 3 sandwiching the magnetoresistive element 4 was made of Al2O3, and the sum of the film thicknesses at the portions sandwiching the magnetoresistive element 4 was 1 μm.

The upper and lower magnetic poles 8 and 5 are coated with a Ni film with a thickness of μm.
-Fe alloy was used. The magnetostriction of the Ni-Fe alloy film was adjusted by changing the composition. Let the magnetostriction at that time be λS. As the insulating layer 6 that forms the gap between the upper and lower magnetic poles 8.5, an A1□O3 film with a thickness of 1 μm was used.

The conductor coil 7 was a copper pattern with a film thickness of 2 μm, and was processed by ion milling. The flattening layer 61 was made of polyimide resin PIQ (manufactured by Hitachi Chemical Co., Ltd., trade name), and the taper etching was carried out by chemical etching using a solution containing ethylenediamine as a main component using a photoresist as a mask. For the uppermost protective film 9, an Al, O, film was used.

FIG. 1 shows the relationship between the optimum recording current value of the composite thin film magnetic head shown in this embodiment and the magnetostriction of the pole magnetic film of the inductive thin film magnetic head, using the thickness of the pole magnetic film as a parameter. The medium used for the measurement was Co with a coercive force of 10,000 e.
-Ni-Zr sputtering medium.

Here, the optimum recording current value is defined as follows.

This was used as an index of recording efficiency. In other words, when we examine the relationship between the recording current and playback output when a 5kPCI signal is recorded on a medium using a composite recording head and read back using a playback-only (magnetoresistive element) head, we find that the playback output begins to saturate. The recording current value was defined as the optimum recording current value. When the film thickness was small, the optimum recording current value was almost the same regardless of whether the magnetostriction was positive or negative.

It can be seen that when the film thickness is 3 μm or more, the optimal recording current value increases rapidly when the magnetostriction is negative, whereas the optimal recording current value is low when the magnetostriction is positive, and the recording efficiency is excellent.

Note that the magnetostriction of the magnetic film used in the magnetic head needs to be as small as possible in order to avoid changes in magnetic properties due to stress during processing, and is preferably 1×10 or 6 or less.

Figure 2 (a) shows a magnetic pole with a magnetic pole film thickness of 3 μm and a magnetostriction of 3×10 or 7, and Figure 2 (b) shows a magnetic pole with a magnetic pole film thickness of 3 μm and a magnetostriction of -
The magnetic domain structure of the magnetic pole of IX10+' is shown. The magnetic domain structure was observed by the Bitter method.

The magnetic pole with positive magnetostriction formed a reflux magnetic domain structure in which the direction of easy magnetization of the magnetic film faced the track width direction, whereas the magnetic pole with negative magnetostriction formed a striped magnetic domain exhibiting perpendicular anisotropy. .

Thus, it is considered that the magnetic pole with negative magnetostriction exhibits perpendicular anisotropy when the film thickness is large, and thus the recording efficiency is reduced. In the above embodiment, Ni-Fe alloy (permalloy)
However, similar effects were obtained in the case of an amorphous alloy such as CoTaZr, or a multilayer film of Fe--C and Ni--Fe alloy (permalloy).

Note that in the conventional inductive thin film magnetic head that performs self-recording and reproducing, the thickness of the pole magnetic film must be less than 3 μm from the viewpoint of reproduction resolution. At this time, as shown in Figure 1, -5
There is no deterioration in recording efficiency even in the negative magnetostriction range from X10 and 7 to O. Furthermore, when the magnetostriction of the magnetic pole magnetic film was made positive, no deterioration in recording efficiency was observed, but distortion was observed in the reproduced signal, causing noise. In the composite thin film magnetic head, since the inductive thin film magnetic head that forms it does not perform reproduction, there is no problem even if the magnetostriction of the pole magnetic film becomes positive.

(Effect of the Invention 1) According to the present invention, perpendicular anisotropy is not induced even if the pole magnetic film is thick, so that a composite magnetic head having a recording head with excellent recording efficiency can be obtained.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the magnetostriction of the magnetic pole magnetic film and the optimum recording current value of an inductive thin film magnetic head that forms a composite thin film magnetic head, using the thickness of the magnetic film as a parameter. , a diagram showing the relationship between the magnetic domain structure vA observed in the magnetic pole of the inductive thin film magnetic head forming the composite thin III magnetic head and the magnetostriction of the magnetic pole magnetic film. Figure 3 is a cross section of the composite thin film magnetic head. It is a diagram. Explanation of symbols 1...Substrate, 2...Shield pattern, 3...l
I! Edge layer, 4... Magnetoresistive element, 5... Lower magnetic pole. 6... Insulating layer, 7... Conductor coil, 8... Upper magnetic pole, 9... Protective film strain λβth (c.

Claims (1)

[Claims] 1. In a composite thin film magnetic head comprising a magnetoresistive thin film magnetic head and an inductive thin film magnetic head, the magnetostriction of the magnetic film forming the magnetic pole of the inductive thin film magnetic head is positive. A composite thin-film magnetic head featuring: 2. The composite thin film magnetic head according to claim 1, wherein the magnetic film forming the magnetic pole of the inductive thin film magnetic head has a thickness of 3 μm or more and a magnetostriction of 0 or more and 1×10_+^6 or less. head.