JPS5837835A - Magneto-resistance effect type magnetic head - Google Patents

Abstract

PURPOSE:To facilitate the control of a bias magnetic field and to stabilize the characteristics for a magneto-resistance effect type magnetic head, by setting a permanent magnet film and a conductor layer holding a thin film magneto- resistance effect element between them on a substrate. CONSTITUTION:An insulated layer 29 or SiO2, etc. is coated when necessary on a substrate 21, and at the same time an insulated permanent magnet film 22 of about 2,000-3,000Angstrom thickness is formed on the substrate 21 to generate a bias magnetic field. A thin film magneto-resistance effect element 23 is formed on the film 22 via an Fe-Ni alloy, etc. of about 300-500Angstrom . In addition, a conductor layer 24 for generation of bias magnetic field is formed on the element 23 with about 500-1,500Angstrom thickness via a Ta-Si group alloy, etc. A terminal conductor layer 30 is coated and led out from the upper parts of both ends of the layer 24. With use of such magnetic head, a magnetic field obtained by synthesizing a magnetic field generated from the layer 24 and a magnetic field produced from the film 22 flows to the element 23 to avoid the oxidation of the element 23.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetoresistive (hereinafter referred to as MR) effect magnetic head.

It is known that a reproducing magnetic head using an MR effect magnetic head is superior in narrow track reproducing, short wavelength reproducing, and ultra-low speed reproducing compared to a general electromagnetic induction type reproducing magnetic head.

As an example of a magnetic head made of MR effect, as shown in FIG. A conductor layer (3) is deposited on top of which an insulating layer (3) is applied.
There is a device in which a thin gMR element (51) is adhered through a permanent magnetic field I
I (2) Combination of the magnetic field due to K and the magnetic field generated by passing a current through the conductor layer (3) - The magnetic field gives the thin MR element (5) a bias magnetic field of the required direction and magnitude. The thin film MR device (5) is designed to operate with high sensitivity and excellent linearity.

(6) is the surface in contact with the magnetic medium, and the end face of the K thin 11 MR element (5) faces this surface, and the surface facing the magnetic medium in the thickness direction of this thin J [MR element (51) The direction of target migration is selected.

However, in the MR effect magnetic head with such a configuration, an insulating layer (4) is interposed between the thin i[MR element (51) and the conductor layer (3) for applying a bias magnetic field thereto. Furthermore, a conductive layer (3) and an insulating layer (4) are interposed between the thin film MR element (5) and the permanent magnet film (2) for similarly applying a bias magnetic field. It is necessary to generate a relatively large magnetic field in the conductor layer (3) and the permanent magnet II (23), and it is necessary to pass a large current through the conductor layer (3). ), it is difficult to adjust the composite magnetic field of both magnetic fields, that is, the bias magnetic field, applied to the MR element T5j, and it is relatively troublesome to obtain a magnetic head with stable and uniform characteristics.

The present invention provides an MR effect magnetic head of this type that eliminates these drawbacks.

The present invention will be described in detail with reference to FIG.

In the present invention, a base Qυ is provided, and an insulating permanent magnet film for generating a bias magnetic field, a thin film MR element, and a conductor layer (b) for generating a bias magnetic field are sequentially arranged on this.

The example shown is a case where a specially shielded structure is adopted, and in this case, the base 3D is made of a high magnetic permeability magnetic material, such as Ni-Zn-based or Mn-Zn-based ferrite, and this base 3D is made of these ferrites. If it has conductivity like Ksto! The insulating layer (2) is 3QOO1
Deposited to a thickness of ~5000X.

The permanent magnet film for generating a bias magnetic field formed on the base body 3 has a thickness of about 20001 to 30 UOX, and its magnetic properties include a saturation magnetic flux density Bs of 300 tl to 4000 tl.
Gauss, coercive force Hc is 80000e, angle ratio Rs is o
, s, and is made of an iron oxide magnetic film having a high specific resistance value, such as r-Fe20z, Pez04 ic, and is magnetized. Note that this iron oxide magnetic film can be formed by sputtering or vapor deposition using a mixed gas of argon and IIl, and in this case, even if it is formed by such a method, there is a thin film underneath. Since no MR element is present, there is no risk of the MR element becoming t's due to oxygen during the formation of this magnetic film, that is, the magnet film Ω, and affecting its magnetic properties.

Then, on this permanent magnet film @, a thin film MR element cat/
, Fe-Ni alloy with a thickness of about 300X to 500X,
Alternatively, it may be formed from N1-Go gold alloy, F.-An-8i alloy, or the like.

Furthermore, a conductor layer (b) for generating a bias magnetic field is deposited on this thin film MR element, and this conductor layer (to)
is chemically stable and has low diffusion into thin film MR elements.
In addition, a metal film whose specific resistance value is close to that of the thin film MR element (c), such as a single metal such as Ta, Nb, St, 1ldo, W, etc., or an alloy of two or more of these metals, such as a Ta=8i alloy. , or Mo, W, Ta, Nb.

81, and its thickness is selected from 500x to 1500xK depending on these resistors.

The insulating permanent magnet film @f1 film MR element (c) and the conductor layer (to) are sequentially deposited on the entire surface of the substrate υ, and then simultaneously etched into a strip shape, for example, by a dry etching method, for example, ion etching. can be patterned into the same pattern.

Then, an insulating layer, e.g., 8i02 layer, having a thickness of, for example, K 3000X to 500 (IXQ degrees) is deposited by a known technique on the entire surface including the conductor layer for generating the bias magnetic field. The other reinforcing base is placed on top of the adhesive (to) K, and the base has a magnetic shielding effect (7).
3), that is, a high magnetic permeability substrate such as Ni-Zn ferrite or Mn-Zn ferrite is bonded, and a thin film MR element and a bias placed between them are bonded to both substrates (21) and @seki. It has a structure in which a permanent magnet film for generating a magnetic field and a conductor layer are sandwiched.

Incidentally, as shown in FIG. 3, the terminal conductor layer ctlt/coating layer can be led out from both ends of the conductor layer @.

Kyota*2 In the figure, (to) is the mirror-polished surface that faces the magnetic medium, and this pair! The end face of the thin film MR element (c) faces one surface (to), and the direction of relative movement of the magnetic medium is selected in the thickness direction of this thin film MR element Ω.

In addition, in the above configuration, the distance d between both substrates 31J and (3) is such that the insulation between the thin film MR element and the substrate (211) and between the conductor layer c!4 and the substrate (5) is The thickness of the insulating layers (to) and (c) can be selected to the extent that it can be ensured, and the spacing is 1 to 1.5 μm to ensure a magnetic shielding effect.
It is desirable to select

In the example A mentioned above, the base body 3υ and the fin are made of a high permeability magnetic material, but it goes without saying that these base materials (211 and the fin are made of a non-magnetic material with a high permeability magnetic layer, for example, a thick It is also possible to have a structure in which a vapor-deposited layer of Fe--Ni (permalloy) with a thickness of 2 μm is deposited.

In the magnetic head according to the above-described structure of the present invention, a current wire is connected to the terminal conductor layer. At this time, since the conductor layer (G) and the thin film M-layer (C) are selected to have almost the same specific resistance, current flows through both, and the conductor layer G! The current flowing through 41 generates a magnetic field, which is applied to MR element q#C. That is, the combined magnetic field of this magnetic field and the magnetic field of the permanent magnet film is the magnetic field of the MR element c23.
#/c given. On the other hand, the resistance change due to the signal magnetic field applied from the magnetic medium by the current flowing through the thin film MR element (23) is detected. In this case, the output voltage is determined not only by the resistance of the MR element but also by the conductor layer C24 in parallel with it. K
A resistor will be inserted. Therefore, the conductor layer■
Increasing the resistance of the conductor layer (2) will be advantageous for the output voltage, but in this case, the heat generation of the conductor layer (2) will increase, and the bias magnetic field obtained will thereby become smaller. It is desirable that the resistivity value be approximately the same as or appropriately larger than this value.

In addition, it is a must! Depending on the situation, an insulating layer with a thickness of about 200×, for example, about 200× can be seeded on the permanent magnet film so that only the purpose of flattening the surface thereof is achieved.

As mentioned above, the MRfi magnetic head according to the present invention has the following features:
Since a permanent magnet HcQ and a conductor layer @ are arranged to sandwich the MR element and almost directly contact it to apply a bias magnetic field to it, the magnetic field QMR is effectively It can be applied to element c3. Furthermore, as described above, since the permanent magnet film (1) can be formed in the absence of the MR element, the inconvenience of oxidizing the element g3k can be avoided. There is also the effect that the distance between the shield base 3g and the product can be made small.

Incidentally, conventionally, as shown in FIG. 4, a cross section of the main part of which is shown, a magnetic layer 1 having a magnetic shielding effect is placed on the base CIJ.
v1#, a conductive permanent magnet film e4t is formed on this via an insulating layer, and then a thin film MR element (total) is deposited on this via an insulating layer. Insulating layer (9) on top
Through the a-ki shield effect! Some have a structure in which a magnetic layer (to) having .

In this case, the MR element (to) is given a bias magnetic field by a composite magnetic field of the magnetic field of the permanent magnet film itself and the magnetic field generated by passing this through Ktfi. In the head, the insulating layer is, for example, 5to2EJ with a thickness of about 3000X.
Since a thick insulating layer with no pinholes etc. is required, the distance between the magnet *G41 and the MR element (to) is large.
On the other hand, when sliding with a magnetic medium, the two are electrically short-circuited. Moreover, since the magnet film (2) of the magnetic field generating means and the MR element (to) are spaced apart as in the conventional example explained in FIG. Both the upper and lower parts of the base are 11
In order to prevent the bias magnetic field from escaping, it is necessary to make the distance between the magnet film and the magnetic layer or base of the magnetic shield sufficiently large. There are disadvantages such as a large amount of

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of the main part of a conventional magnetoresistive magnetic head, FIG. II2 is an enlarged sectional view of the main part of the magnetoresistive ffi magnetic head according to the present invention, and FIG. Figure, Figure 4 is the conventional! 2 is an enlarged cross-section of a main part of another example of a pneumatic resistive magnetic head. 01) is the base, (2) is the insulating layer on top of it, is an insulating permanent magnet film for bias magnetic field generation, is the thin film magnetoresistive element, and (to) is the conductor layer for bias magnetic field generation. be. Continued from page 1 0 Inventor Tetsuo Sekiya 4-14-1 Asahimachi, Atsugi City Sony Corporation Atsugi Factory

Claims (1)

[Claims] A magnetoresistive magnetic head in which an insulating permanent magnet film for generating a bias magnetic field, a magnetoresistive element film, and a conductor layer for generating a bias magnetic field are sequentially laminated on a substrate.