JPS63292408A - Magneto-resistance effect type magnetic head - Google Patents

Abstract

PURPOSE:To prevent the leakage of a magnetic flux of a signal magnetic field on the end face, and also, to improve the reproducing efficiency of a magnetic head by forming each of the opposed end faces of a pair of yokes so that parts being nearer a magneto-resistance effect element approach each other. CONSTITUTION:Each of end faces 4a, 5a of both opposed yokes 4, 5 on a magneto-resistance effect element 1 is formed on the inclined or curved surface so that parts being nearer the magnet-resistance effect element 1 approach each other. According to this structure, as for the end faces 4a, 5b of both the yokes 4, 5 opposed on the magneto-resistance effect element 1, a distance between each other becomes layer toward the upper part, its cap becomes larger and a magnetic flux comes to scarcely leak, the generation of a leakage magnetic flux flowing directly between the end faces 4a, 5a of both the yokes 4, 5 is suppressed, and the magnetic flux is applied concentrically to the magneto-resistance effect element 1.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetoresistive magnetic head (hereinafter abbreviated as MR head), and particularly relates to a magnetoresistive effect element (hereinafter referred to as MR head).
The present invention relates to a so-called yoke-type MR head in which a pair of yokes (abbreviated as X-element) are provided facing each other for applying a signal magnetic field to the MR element.

[Prior Art] Before describing the conventional structure of this type of MR head, the operating principle of an MR element will be explained using FIG. 5.

In FIG. 5, the symbol 1 is an MR element, -
It consists of a strip-shaped ferromagnetic thin film with axial magnetic anisotropy. The magnetic anisotropy of the MR element 1 is made parallel to the longitudinal direction of the band of the MR element 1 in advance, and a constant current 1 is caused to flow through the MR element 1 via the signal electrode 2.2.The magnetization of the MR element 1 at this time is The direction EA is oriented in the longitudinal direction of the MR element 1 and is parallel to the current direction.

When an external magnetic field Hs is applied perpendicularly to the longitudinal direction of the MR3R3 element in this state, the strength of the external magnetic field Hs causes the MR element 1 to
The magnetization direction M changes so that it forms a certain angle 0 with the current direction. At this time, the resistance value R of the MR element changes as shown in FIG. 6 while maintaining the relationship R=Ro+ΔRmaxXcos20. 6th
The relationship between the external magnetic field Hs and the resistance value R of the MR element 1 shown in the figure is called the R-H characteristic.

Therefore, if a constant current i is caused to flow through the MR element I, a change in the external magnetic field Hs is taken out from the signal electrode 2.2 as a voltage change due to a change in the resistance of the MR element I, that is, as a signal.

Next, we will introduce the conventional structure of an MR head based on this principle in the third section.
This will be explained with reference to FIGS. For the sake of clarity, FIG. 3 is shown with the insulating layers 7 to 9 and the protective film IO in FIG. 4 removed.

As shown in FIGS. 3 and 4, insulating layers 7 to 9 are formed on a magnetic substrate 6 by forming thin film patterns of an MR element 1, signal electrodes 2, 2, bias electrode 3, front yoke 4, and tail yoke 5, respectively. The MR head is constructed by laminating the layers through a thin film deposition method. A protective w1 film 10 is then provided over all of these. Further, reference numeral 11 is a magnetic gap.

12 is a back through hole formed in the insulating layer 7.

Note that in this structure, the signal electrode 2.2 is M as described above.
This is for extracting a signal from the R element l. Further, the bias electrode 3 is for applying a bias magnetic field to the MR element 1. Further, the front yoke 4 and the tail yoke 5 are for applying an external signal magnetic field to the MR element 1, and are provided on the MR element 1 to face each other. As shown in Fig. 4, both yokes 4°5 facing each other on the MR element l.
The respective end faces 4a and 5a are formed on a plane substantially perpendicular to the MR element 1, and are formed substantially parallel to each other.

When reproducing signals under such a structure, bias '7
'rt, an external signal magnetic field is picked up from the front yoke 4 while a bias magnetic field is applied to the MR element 1 via the pole 3, and the magnetic flux of the signal magnetic field is transferred from the yoke 4 to the MR element as shown by the broken line in FIG. The signal flows through the element 1, the tail yoke 5, and the magnetic substrate 6 forming a closed loop, and is applied to the MR element 1. According to the above-described operating principle, the resistance of the MR element 1 changes in response to changes in the signal magnetic field, which is extracted as a signal from the signal electrode 2.2.

This type of yoke type MR head has a higher MR head than other shield type or front type MR heads.
It is highly reliable because the element does not come into direct contact with the magnetic recording medium, and has the best environmental resistance against corrosion and wear.

[Problems to be Solved by the Invention] However, in the structure described above, as shown by the broken line in FIG. A phenomenon occurs in which the liquid leaks from the upper part of the figure, which is away from the MR element 1 of 4a, and directly flows to the tail yoke 5 without flowing to the MR element 1. As a result, the signal magnetic field is not concentrated on the MR element 1, resulting in a reduction in the reproduction efficiency of the MR head.

On the other hand, in order to improve the reproduction efficiency of the MR head,
It is possible to reduce the magnetic resistance of the magnetic path through which the magnetic flux of the signal magnetic field flows, and for this purpose, the opposing end surfaces 4a and 5a of both yokes 4.5 may be brought closer to each other, or both yokes 4.5 may be brought closer to each other.
One possible method is to increase the thickness of 5. However, no matter which structure is adopted, magnetic leakage from the end surface 4a of the front yoke 4 to the tail yoke 5 will be promoted.

In addition, especially in the former structure, the length of the portion of both yokes 4.5 extending above the MR element l becomes long, the effective length of the MR element l becomes short, and the rate of change of magnetoresistance of the MR element l decreases. In any case, the regeneration efficiency cannot be improved.

[Means for Solving the Problems] In order to solve these problems, according to the present invention, a pair of yokes for applying a signal magnetic field to the magnetoresistive element are provided facing each other on the magnetoresistive element. In the magnetoresistive magnetic head, a structure is adopted in which the mutually opposing end surfaces of the pair of yokes are formed into inclined or curved surfaces such that the portions closer to the magnetoresistive element are closer to each other.

[Function] With this structure, the magnetic flux of the signal magnetic field easily leaks between the end faces of the opposing yokes in the conventional structure.
The farther the parts are from the R element, the more they are separated from each other and the gap becomes larger, making it difficult for magnetic flux to leak. Most of the magnetic flux of the signal magnetic field is concentratedly applied to the MR element, improving the reproduction efficiency of the MR head.

[Example] Examples of the present invention will be described in detail below.

1 and 2 are perspective views and sectional views for explaining the structure and operation of the MR head according to the embodiment of the present invention. Both figures are common or equivalent to those in FIGS. 3 and 4 of the conventional example. Parts are given the same reference numerals. Note that FIG. 1 is shown with the insulating layer and the like removed, similar to FIG. 3 of the conventional example.

As shown in FIGS. 1 and 2, the basic structure of the MR head of this embodiment is the same as that of the prior art example described above. That is, an MR element 1, a signal electrode 2.2, and a bias electrode 3 are arranged on a magnetic substrate 6.
, the front yoke 4 and the tail yoke 5 are each provided as a thin film pattern and laminated with insulating layers 7 to 9 interposed therebetween.
R head is configured. And keep on the whole *n*io
is provided. The details of each member will be explained below along with the manufacturing process of the MR head.

First, the magnetic substrate 6 is formed from Mn-Zn ferrite or the like. In the manufacturing process, first an insulator W is placed on this magnetic substrate 6.
+7 is formed from 5i02 or Aj2203 to a thickness of several JLm by a thin film deposition method.

Next, a bias electrode 3 is formed on the insulating layer 7 by a thin film deposition method using AJ, Cu, etc., and processed into the pattern shown in the figure by etching.

Next, an insulating layer 8 is formed from the same material as the insulating layer 7 so as to cover the bias electrode 3 .

Next, signal electrodes 2, 2 are formed of AI, Cu, etc. on the insulating layer 8, and processed into the illustrated pattern by etching.

Next, the MR element 1 is mounted on the insulating layer 8 by several hundred amperes of Ni-Fe or the like.
formed as a thin ferromagnetic film with a thickness of

The shape shown in the figure is formed by wet etching or ion etching. Both ends of the MR element l are connected to each of the signal electrodes 2.2.

Next, an insulating layer 9 is formed on the MR element l, and an insulating layer 7 is formed on the MR element l.
．． By ion etching 9, the magnetic gap 1 is
1 and a back through hole 12 are formed.

Next, the front yoke 4 and the tail yoke 5 are formed as thin films made of a ferromagnetic material such as permalloy, sendust, or amorphous. The front yoke 4 is formed to extend from above the magnetic gap 11 onto the insulating layer 9 so as to face the MR element.

The tip of the tail yoke 5 faces the MR element l on the insulating layer 9, and the rear end faces the magnetic substrate 6 via the back through hole 12.
The two yokes 4.5 formed so as to be in contact with the MR element 1 are provided so as to overlap by several #Lm with respect to the MR element 1.

Furthermore, the entire surface above each pattern above is 5t02 or A.
The MR head is completed by covering with an insulating protection 1410 made of ff1203 or the like.

By the way, the structure of the above-mentioned parts is the same as that of the conventional example, but in this example, the difference from the conventional example is that the end surfaces 4 of both yokes 4 and 5 facing each other on the MR element l are different from the conventional example as shown in FIG.
a, 5a are each formed into an inclined surface such that the portion closer to the MR element l approaches each other.
, 5a with respect to the MR element 1 is, for example, 45°.

Further, the inclinations of both end surfaces 4a and 5a are formed by appropriately controlling the etching when forming both yokes 4 and 5 by ion etching or the like.

According to such a structure, on the end faces aa and sa of both yokes 4.5 facing each other on the MR element l, leakage of the magnetic flux of the signal magnetic field is likely to occur in the conventional structure, and the tjIJ2 diagram is located away from the MR element l. The distance between them increases toward the upper middle portion, and the gap becomes larger, making it difficult for magnetic flux to leak. As a result, the flow of the magnetic flux of the signal magnetic field picked up from the front yoke 4 in FIG.
The generation of leakage magnetic flux directly flowing between the end surfaces 4a and 5a is suppressed, and the magnetic flux is concentrated and applied to the MR element 1.

As a result, the reproduction efficiency of the MR head can be improved compared to the conventional one.

In addition, in the configuration described below, the end surfaces 4a, 5 of both yokes 4.5
Of course, the inclination angle of a is not limited to 45°,
In short, it is sufficient that the parts closer to the MR element l are inclined so that they approach each other, and both end surfaces 4a and 5a are closer to the MR element l.
It may be formed into a curved surface as long as the portions closer to each other are closer to each other.

[Effects of the Invention] As is clear from the description below, according to the present invention, a magnetoresistive type magnetic field is provided, in which a pair of yokes for applying a signal magnetic field to a magnetoresistive element are provided facing each other on the magnetoresistive element. In the head, the mutually opposing end surfaces of the pair of yokes are formed into sloped or curved surfaces such that the portions closer to the magnetoresistive element approach each other, so that the magnetic flux of the signal magnetic field at the end surfaces is reduced. The excellent effects of suppressing the leakage and improving the reproduction efficiency of the MR head can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main parts of the MR head according to an embodiment of the present invention, and FIG. 2 is a sectional view of the main parts of the head.
Fig. 3 is a perspective view of the main parts explaining the structure of a conventional MR head, Fig. 4 is a sectional view of the head, Fig. 5 is an illustration of the operating principle of the MR element, and Fig. 6 is the R-H characteristic. FIG. 1... MR element 2... Signal electrode 3... Bias electrode 4... Front yoke 5... Tail yoke 6... Magnetic substrate 7-9... Insulating layer
10... Protective film patent applicant Canon Electronics Co., Ltd. 7F! 'Department's#Ne屹mon No. 30 MR #3's Kimimata Shokan IQ Montomen No. 5 R Kaede R-H special trend No. 1 Campan No. 6

Claims (1)

[Claims] In a magnetoresistive magnetic head in which a pair of yokes for applying a signal magnetic field to the magnetoresistive element are provided facing each other, each end face of the pair of yokes facing each other is connected to the magnetoresistive element. 1. A magnetoresistive magnetic head, characterized in that it is formed with an inclined or curved surface such that portions closer to each other approach each other.