JPH048847B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a magnetoresistive thin film magnetic head suitable for reproducing signals magnetically recorded at short wavelengths.

(b) Prior art In general, in order to improve the short wavelength reproduction characteristics of a magnetoresistive thin film magnetic head, a magnetoresistive element layer is arranged in a gap (for example, about 1 μm) between magnetic shielding layers to transmit adjacent signals. It is effective to reduce the effective spacing loss by reducing the influence of the magnetic field, and by making the magnetoresistive element layer sensitive only near the recording medium sliding surface under a strong bias magnetic field (for example, about 200 Oe). It is.

However, in order to obtain a magnetoresistive thin film magnetic head with good short wavelength reproduction characteristics that combines the effects of the magnetic shield and the strong bias magnetic field described above, the following points must be fully considered. That is, first, a strong bias magnetic field can be applied;
Moreover, it is provided with a bias magnetic field generating means that can easily control the strength of the bias magnetic field and set it to an appropriate value. Thirdly, a magnetic shielding layer, a magnetoresistive element layer, a conductive layer for a current-carrying terminal,
The object of the present invention is to create a structure in which electrical conduction and insulation, particularly at the stepped portions of the ends of each pattern, of the bias magnetic field generating means layer, etc., can be sufficiently achieved depending on the respective purpose.

However, the prior art has not been able to provide a highly reliable magnetoresistive thin film magnetic head that fully satisfies the above points.

(c) Object of the Invention The present invention has been made in view of the above points, and an object thereof is to provide a magnetoresistive thin film magnetic head which has excellent short wavelength reproduction characteristics and is highly reliable.

(d) Structure of the Invention That is, in order to achieve the above-mentioned object, the present invention provides at least a first magnetic shield layer, a first electric and magnetic insulating layer, and a magnetoresistive layer on a first non-magnetic substrate. After sequentially forming the element layer, the conductive layer for current-carrying terminals, the second electric/magnetic insulating layer, and the second magnetic shielding layer/bias magnetic field generation conductive layer, a second non-magnetic substrate is used for reinforcement. The magnetoresistive thin film magnetic head is formed by bonding a magnetoresistive thin film magnetic head, in which the end surfaces of the layers other than the conductor layer for the current-carrying terminal are exposed to the recording medium sliding surface side, and
magnetic shield layer, magnetoresistive element layer, second
The width in the direction perpendicular to the recording medium sliding surface of the magnetic shielding layer/bias magnetic field generation conductor layer of
Ws1, WMR, Ws2, and when the distance from the recording medium sliding surface to the tip of the connection part of the conductor layer for the current-carrying terminal with the magnetoresistive element layer is d, WMR<Ws2
<d<Ws1.

(E) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

Here, FIG. 1 is a schematic plan view showing an example of the magnetoresistive thin film magnetic head according to the present invention in the vicinity of one track of the magnetoresistive element layer, and FIG. 2 is a line A-A' in FIG. FIG.

In the figure, 1 is the first non-magnetic substrate (e.g. photoceram, soda glass), 2 is the first magnetic shield layer (e.g. permalloy, sendust, film thickness 0.1 μm), and 3 is the first electrical and magnetic insulator. layer (e.g. SiO ₂ , Al ₂ O ₃ , film thickness 0.1 to 1 μm), 4 is a magnetoresistive element layer (e.g. permalloy, film thickness 0.03 μm).
~0.06μm), 5 is a conductor layer for current-carrying terminal (e.g.
Cu, Au, Al, film thickness 0.3-1μm...as adhesive layer
0.01~0.1μm Cr, Ti may be laminated),
6 is a second electrically and magnetically insulating layer (e.g. SiO ₂ ,
Al ₂ O ₃ , film thickness 0.1 to 1 μm), 7 is a second magnetic shielding layer and bias magnetic field generation conductor layer (for example,
Conductive high permeability magnetic material such as permalloy or sendust, film thickness 0.1 to 1 μm), 8 is a coating layer (e.g.
SiO ₂ , Al ₂ O ₃ film thickness: 0.1 to 1 μm), and P indicates the recording medium sliding surface side. In reality, a second non-magnetic substrate (for example, photoceram, soda glass) is bonded onto the coating layer 8 via a glass-based or epoxy-based adhesive, 0.1 to 1 mm from the recording medium sliding surface.
A bulk permanent magnet 9 (for example, SmCo ₅ , alnico, Ba ferrite...magnetized in the stripe width direction of the magnetoresistive element layer 4 ) for generating a bias magnetic field is arranged on the covering layer 8 at a distant position. be done.

As described above, in the magnetoresistive thin film magnetic head according to the present invention, the first magnetic shield layer 2, the first electric/magnetic insulating layer 3, and the magnetoresistive element layer are disposed on the first nonmagnetic substrate 1. 4. The conductive layer 5 for current-carrying terminals, the second electrically magnetic insulating layer 6, the second magnetic shielding layer/bias magnetic field generation conductive layer 7, and the covering layer 8 are formed into a predetermined shape in the above order. Among the layers, at least the end surfaces of the layers other than the conductor layer 5 for current-carrying terminals are exposed to the recording medium sliding surface. Furthermore, the widths of the first magnetic shield layer 2, the magnetoresistive element layer 4, and the second magnetic shield layer/bias magnetic field generation conductor layer 7 in the direction perpendicular to the recording medium sliding surface are Ws1 and WMR, respectively. , Ws2, and when the distance from the recording medium sliding surface P of the tip of the connection part of the conductor layer 5 for the current-carrying terminal with the magnetoresistive element layer 4 is d, WMR is such that Ws2<d<Ws1. It is composed of Specifically, WMR5μ
m, Ws about 210 μm, d about 15 μm, and Ws about 120 μm.

Here, a bulk permanent magnet 9 is arranged at a position slightly apart from the magnetoresistive element layer 4, and a second magnetic shielding layer/bias magnetic field generation conductor layer is arranged near the magnetoresistive element layer 4. 7 is used together with such a bulk permanent magnet 9.
In addition to generating a main strong bias magnetic field, the auxiliary bias magnetic field generated from the conductive layer 7 is changed by controlling the current flowing through the conductive layer 7, thereby acting on the magnetoresistive element layer 4. This is to finely adjust the strength of the bias magnetic field.

Further, the magnetic shielding means is provided in the magnetoresistive element layer 4.
The distance l1 between the magnetic shielding means and the bulk permanent magnet 9 is necessarily the same as the distance l1 between the magnetoresistive element layer 4 and the bulk permanent magnet 9. (Specifically, if the distance dM from the recording medium sliding surface P to the bulk permanent magnet 9 is 500 μm, then since WMR<Ws2〓dM, l1=(dM−
Furthermore, since the difference in film thickness between the magnetic shield layers 2 and 7 and the magnetoresistive element 4 is not too large, the bias magnetic field is applied to the magnetoresistive element layer 4. It can also work well. Even a magnetic shield layer with this thickness inevitably has a structure that extends long in the direction perpendicular to the bias magnetic field.
At least the vicinity of the recording medium sliding surface is not saturated in the direction of the bias magnetic field, and the effect of shielding adjacent signals on the recording medium is sufficient.

Further, in the present invention, the first magnetic shield layer 2,
The widths of the magnetoresistive element layer 4 and the second magnetic shield layer/bias magnetic field generation conductor layer 7 in the direction perpendicular to the recording medium sliding surface P are WMR<Ws2<d, respectively.
By configuring the structure such that <Ws1, electrical conduction and insulation between each layer (particularly at stepped portions) can be sufficiently achieved according to each purpose. That is, d≠0 here means that the tip of the conductor layer 5 for the current-carrying terminal, which is generally formed of Cu, Au, Al, etc. that easily undergoes plastic deformation, is exposed on the recording medium sliding surface P side. This is to prevent an electrical short circuit from occurring through the medium sliding surface with the surrounding first magnetic shield layer 2 or the second magnetic shield layer/bias magnetic field generating conductor layer 7. Also,
WMR<Ws1 and WMR<Ws2 are set because the first magnetic shield layer 2 and the second magnetic shield layer/bias magnetic field generation conductor layer 7 tightly cover the magnetoresistive element layer 4 to achieve a shielding effect. This is to enable them to perform to their full potential. The reason why Ws2<d is set is because the second magnetic and electrical insulating layer 6 becomes thinner at the step part at the tip of the conductor layer 5 for the current-carrying terminal, so that the second magnetic shield layer and the bias magnetic field are formed on this layer. This is to prevent a large risk of an electrical short circuit with the current-carrying terminal conductor layer 5 if it is covered by the generation conductor layer 7. Furthermore, d<Ws1 is a very thin magnetoresistive element formed at the stepped portion at the end of the first magnetic shield layer 2 with the first magnetic and electrical insulating layer 3 interposed therebetween. There is a great risk that the current-carrying terminal draw-out portion 4' of the layer 4 (for connecting with the conductor layer 5 for the current-carrying terminal) cannot cover the step and is disconnected. This is because the structure is such that electrical continuity is compensated for by covering the conductor layer 5 for current-carrying terminals which is sufficiently thicker than the magnetoresistive element layer.

(F) Effects of the Invention As described above, the magnetoresistive thin film magnetic head according to the present invention utilizes both the effect of magnetic shielding and the effect of a strong bias magnetic field, that is, the magnetoresistive element layer is formed with a narrow gap. By placing it between magnetic shield layers, the influence of adjacent signals is reduced, and by effectively applying a strong bias magnetic field to the magnetoresistive element layer, the ability to reproduce signals recorded at short wavelengths is improved. can be improved.

Furthermore, in the present invention, consideration is given to electrical conduction and insulation at the stepped portion between each layer by appropriately setting the width in the direction perpendicular to the recording medium sliding surface of each layer constituting the magnetoresistive thin film magnetic head. Therefore, defects are less likely to occur during the manufacturing process or during use, and reliability can be greatly improved.

[Brief explanation of drawings]

The figures show a magnetoresistive thin film magnetic head according to the present invention, in which FIG.
It is a sectional view taken along line AA' in the figure. 2...First magnetic shielding layer, 3...First electric and magnetic insulating layer, 4...Magnetoresistive element layer, 5...Conductor layer for current-carrying terminal, 6...Second electricity magnetic insulating layer, 7... second magnetic shielding layer and conductive layer for generating bias magnetic field;

Claims (1)

[Claims] 1. On a first non-magnetic substrate, at least a first magnetic shield layer, a first electric and magnetic insulating layer, a magnetoresistive element layer, a conductive layer for a current-carrying terminal, a second A magnetoresistive thin film magnetic head is formed by sequentially forming an electrically magnetic insulating layer and a second magnetic shielding layer, and then bonding a second nonmagnetic substrate for reinforcement, which comprises: The end faces of the layers other than the conductor layer for current-carrying terminals are exposed to the recording medium sliding surface side, and the recording medium sliding of the first magnetic shield layer, the magnetoresistive effect element layer, and the second magnetic shield layer is performed. The width in the direction perpendicular to the surface is Ws1, WMR,
Ws2, and when d is the distance from the recording medium sliding surface of the tip of the connection portion of the conductive layer for the current-carrying terminal with the magnetoresistive element layer, WMR<Ws2<d<Ws1. Magnetoresistive thin film magnetic head. 2. The magnetoresistive thin film magnetic head according to claim 1, wherein the second magnetic shield layer also serves as a conductive layer for generating a bias magnetic field. 3. A bulk permanent magnet is disposed on the first non-magnetic substrate on which each of the layers is formed, at least at a position that does not cover the first magnetic shield layer. 2. The magnetoresistive thin film magnetic head according to item 2.