JPH01116913A - Magneto-resistance type magnetic head - Google Patents

Abstract

PURPOSE:To stabilize magnetic characteristics by extending a couple of electrode conductive layers which are led out of both ends of a magnetism sensing part to both sides in a direction intersecting orthogonally with the application direction of a signal magnetic field to the magnetism sensing part, looping and coupling both extended ends, and thus leading out terminals. CONSTITUTION:A conductor 5 for bias magnetic field production and electrode conductive layers 3 and 4 are extended from the front and rear ends of the magnetism sensing part 2, i.e. in right-left symmetrical relation at least under a shielding magnetic material layer 7. Further, both ends of both electrode conductive layers 3 and 4 which are extended sideward are arranged outside the shielding magnetic material layer 7, or a part of them are coupled mutually by loop parts 33 and 34 while inserted under the arrangement part of the shielding magnetic material layer 7; and 33 and 34 are extended backward and sense current feeding terminals are led out. Consequently, the asymmetry of a magnetic field is released, the influence of the characteristics upon the magnetism sensing part 2 is reduced, and the characteristics are stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetoresistive magnetic head, particularly a shield type magnetic abrasive magnetic head.

[Essentials of invention]

The present invention provides a shield type magnetoresistive magnetic head in which a magnetic sensing part having a magnetoresistive effect is provided on a substrate, and a shielding magnetic layer is arranged to cover the magnetic sensing part. A pair of electrode conductive layers led out from both ends are extended on both sides in a direction perpendicular to the direction in which a signal magnetic field is applied to the magnetically sensitive part, and both extending ends are connected in a loop shape, and a terminal is formed from this loop part. By performing the derivation, it is possible to reduce electrical damage, thereby improving reliability and further stabilizing the magnetic properties.

(Prior art) In a magnetoresistive magnetic head (hereinafter referred to as MR type magnetic head), the magnetic sensing part, that is, the magnetoresistive effect (hereinafter referred to as MR effect) element is formed by two MR effect elements laminated with an insulating layer interposed therebetween. or one of the thin films has an MR effect.
However, an MR type magnetic head in which the other side is composed of a laminated body of magnetic thin films having no or almost no MR effect, and in which a sense current is passed in the same direction through the thin films, is disclosed in Japanese Patent Laid-Open No. 6, for example.
This method is disclosed in Japanese Patent Application Laid-Open No. 1-182620, Japanese Patent Application Laid-Open No. 62-52711, and Japanese Patent Application No. 60-247752. In the MR type magnetic head having such a configuration, the magnetoresistance characteristic of the magnetic sensing portion has a single magnetic domain configuration, and the generation of domain walls is avoided, so that the generation of Barkhausen noise can be suppressed.

Such an MR type magnetic head has at least one MR magnetic head on the base i (1), as shown in FIG. 4 as an enlarged plan view and as shown in FIG. The first and second ferromagnetic thin films (11) and (12)
) are laminated via a non-magnetic intermediate layer (13), the front end surface of which faces the surface (8) that faces or faces the magnetic recording medium, and this surface (8). The magnetic sensing part (2) is arranged so as to extend rearward so as to be orthogonal to the magnetic sensing part (2), and the magnetic sensing part (2) is arranged to extend in the track width direction almost orthogonally to the extending direction of the magnetic sensing part (2) above or below the magnetic sensing part (2). This magnetic sensation a
For the old 2), a bias magnetic field is applied in the direction perpendicular to the track width direction (the direction in which the signal magnetic field is applied to the magnetically sensitive part (21-)), so that the magnetoresistive characteristics in the magnetically sensitive part (2) have linearity. Bias magnetic field generating conductor (
5) are laminated with a surface insulating JM (14) interposed therebetween. On the other hand, at the front end and rear end of the magnetically sensitive part (2),
A sense '6i current i is applied to the magnetic sensing part (2) in a direction substantially perpendicular to the magnetic recording medium or the opposing surface (8), that is, along the direction of the signal magnetic field obtained from the magnetic recording medium.
The front and rear electrodes each serve to apply conductivity Jtj (
31 and (4) are deposited, and a ferromagnetic thin film (11
) and (12) are selected so that the directions of the hard magnetization axes are along the direction of conduction of the signal magnetic field and the sense current l. In this configuration, a change in the resistance of the magnetic sensing part (2) due to a signal magnetic field based on recorded information from the magnetic recording medium is detected as a voltage change at both ends due to the sense current l, and the recording on the magnetic recording medium is reproduced. It is done like this.

In order to improve the resolution of the magnetic head, an MR type magnetic head having such a configuration often has a shield type structure in which magnetic materials are placed above and below the MR effect element, that is, the magnetic sensing part (2). In this case, a magnetic material is used as the substrate (1) to serve as the lower magnetic material, and a magnetic material is used to cover the magnetically sensitive part (2) on this substrate (1) and pass it through the insulation #(6). A shield magnetic layer (7) made of, for example, permalloy (Ni-Fe alloy) and sputtered or plated with a thickness of several micrometers is disposed.

[Problem that the invention seeks to solve]

The present invention aims to further improve and stabilize the characteristics of the shielded MR magnetic head described above.

That is, in the present invention, in the shield type MR magnetic head explained in FIG. 4 and FIG. We will investigate that the magnetic domain state has a large effect on the characteristics, and based on this investigation, we will aim to improve and stabilize the characteristics.

That is, in the above-mentioned shield type MR magnetic head, as shown in FIG. ) and (4) make the surface uneven. That is, in the above configuration, the magnetic sensing part (2
) has a relatively thin overall thickness of, for example, 800 mm discoloration, so even if its edge is under the shielding magnetic material (7), the difference in level will not be much of a problem. However, the bias magnetic field generating conductor (5)
and electrode conductivity r@ (Regarding 31 and (4), the thickness is quite large, for example, about 3,000 people or more, in order to ensure electrical reliability, that is, to avoid disconnection, and to reduce resistance. In order to select the thickness, these bias magnetic field generating conductor (5) and the electrode part'dX layer (
When the edges of 3) and (4) exist under the shield magnetic layer (7), the shield magnetic layer 1→
(7) is deposited, the difference in level at the edge becomes relatively large, and the bending of the shield magnetic layer (7) becomes noticeable at this point.

Now, for example, shield magnetic material i! (Looking at the magnetic domain state when 71 is formed as a flat surface, as shown in Figure 6, the main magnetic domain extends approximately along the axis of easy magnetization and is arranged in parallel at 180°. Incidentally, the thickness of the shielding magnetic layer (7) in this case is several μm, and the magnetostriction is on the order of 10-', which is considered to be almost zero magnetostriction.However, the above-mentioned fourth
As shown in the figure, when the conductor (5) and the electrode conductive layers (3) and (4) are present under the shield magnetic layer (7) as shown by the broken lines in Figure 7, these conductors (5) ) and the bending based on the step caused by the edges of the electrode conductive layers (3) and (4), the bending angle is 18o as shown by the line in FIG.
Random magnetic domains are generated due to distortion or disturbance in the magnetic domains.

When this magnetic domain disturbance occurs especially in the vicinity of the magnetically sensitive part (2), the unstable magnetic domain operation has a large effect on the magnetoresistive characteristics of the magnetically sensitive part (2), which immediately causes a deterioration in the head's protrusion. This results in a worsening of the error rate in the magnetic recording/reproducing system.

The generation of random magnetic domains is caused by the bending of the shield magnetic layer (7) due to the step along the domain wall direction of the 180° magnetic domain, which does not have a large effect on the generation of random magnetic domains, but in the direction orthogonal to this, it has a large effect. It affects it. That is, for example, when the front electrode conductive layer (3) extends only to one side from the front of the magnetically sensitive part (2), as shown in FIG.
), and furthermore, the rear electrode conductive layer (4) is connected to the magnetically sensitive part (
2), when extending rearward in the extension direction of 2), there are steps due to the left and right edges (4a) and (4b) as shown in FIG. 7, especially steps across the axis of easy magnetization. When the front electrode conductive layer (3) and the bias conductor (5) are connected to the shield magnetic layer (7
), if the pattern has a bent part, the step according to the bent shape will create a pattern in the 180' magnetic domain, that is, it will have a great effect on the generation of random magnetic domains, and in particular, this random magnetic domain will be 2), it has a large influence in the vicinity of the surface (8) facing or facing the magnetic recording medium, that is, on the side where the signal magnetic field from the magnetic recording medium is introduced, that is, on the side of the main operating part of the magnetic sensing part (2).

Historically, when the electrodes 4J4 and 1m (3) extend only between one side as shown in the figure, a magnetic field is generated by the sense current i flowing through the electrode conductive layer (3) only on this one side. occurs, so depending on whether the current direction is parallel or antiparallel to the direction of current flow to the bias magnetic field generating conductor (5), the manner in which the actual bias is applied to the magnetically sensitive part (2) varies greatly. , and the left-right asymmetry is large.

The present invention seeks to solve the problems mentioned above.

[Means for solving the problem] In the present invention, FIG. 1 shows a plan view, and FIG.
As shown in the cross-sectional view taken along line A-A in the figure, a pair of ferromagnetic thin films (11) and (12), at least one of which has magnetoresistive properties, is formed on the IJ plate (1) with a non-magnetic intermediate In (13). A magnetically sensitive part (2) laminated with a magnetically sensitive part (2) interposed therebetween;
Apply a sense current i in the same direction as the signal magnetic field from both ends of
Electrode conductive layers (3) and (4) led out in a direction substantially perpendicular to the sense current i direction in this magnetically sensitive part (2);
It has a bias magnetic field generating conductor (5) extending across the magnetically sensitive part (2) via an insulating layer (14), and a shielding magnetic conductor (5) that covers the arrangement part of the magnetically sensitive part (2). Body layer (7)
In the MR type magnetic head, the electrode conductive layers (3) and (4) and the bias magnetic field generating conductor (
5) under the arrangement of the shield magnetic layer (7), almost the entire area thereof, especially the surface facing or facing the magnetic recording medium (
In the main operating part near the front side of the magnetically sensitive part (2) on the side 8), the direction in which the signal magnetic field is applied from the magnetic recording medium, that is, the direction of the difficult magnetization axis, and therefore the direction perpendicular to the sense current direction, π In other words, in the easy magnetization axis direction, the shield magnetic layer (7) is configured to extend over almost the entire area where the shield magnetic layer (7) is arranged so that there are almost no edges or bent portions. In other words, conductor for bias magnetic field generation +5)
, Li electrode conductive layers 3) and (4) are arranged at least under the shielding magnetic material N (7), approximately in the direction of extension of the magnetically sensitive part (2) (i.e., the direction of the magnetization axis and the direction of application of the signal magnetic field). In other words, the electrode conductive layer (
3) and (4) are also extended from both front and rear ends of the magnetic sensing part (2) to both sides, that is, symmetrically to the left and right.

Furthermore, in the present invention, both ends of the picture electrode conductive layers (3) and (4) extending on both sides are arranged outside the shield magnetic layer (7), or a part thereof is covered with the shield magnetic layer. Loop portions (33) and (34) are formed to extend backward and connect to each other so as to extend over the arrangement portion of the layer (7), and are connected to the sense current conducting terminals LSF and tsB, respectively.
Derive.

Further, terminals t1 and t2 through which bias magnetic field generating current is passed are led out from both ends of the bias magnetic field generating conductor (5).

In FIGS. 1 and 2, parts corresponding to those in FIGS. 4 and 5 are designated by the same reference numerals, and redundant explanation will be omitted.

[Effect]

According to the above-described configuration of the present invention, the shield magnetic layer (7)
In the lower part, at least near the magnetically sensitive part (2), especially on the side facing the magnetic recording medium or on the opposing surface (8), that is, in the vicinity of the effective operating part to which the signal magnetic field from the magnetic recording medium is applied, the direction of the hard magnetization axis (The direction of the signal magnetic field and the sense current i) Since there is no edge in the direction along the direction of the signal magnetic field and sense current i, the generation of random magnetic domains is effectively avoided by preventing the formation of a step in the shield magnetic layer (7). is,
This stabilizes the characteristics of the magnetically sensitive section (2) and improves the error rate of the playback device.

In addition to this, each electrode conductor 31 (31 and (
4) extends parallel to the bias magnetic field generating conductor (5),
It extends from the magnetic sensing part to both sides and has a loop part (3
3) and (34) are provided to conduct the energization of essence current 5, as is clear from FIG. A current of i/2, which is the sense current divided into two, is applied to both sides of the center, which reduces the generated magnetic field, and furthermore, the front electrode 4? The asymmetry of the magnetic field is alleviated by energizing directions of each i/2 of the ti layer (3) and the rear electrode conductivity j@ (4) being opposite to each other, and the characteristics for the magnetically sensitive part (2) are This reduces the impact on the product and stabilizes the characteristics.

〔Example〕

An example of the present invention will be further described in detail with reference to FIGS. 1 and 2. The substrate (1) may be composed of a magnetic substrate such as Ni-Zn ferrite + Mn-Zn ferrite, and if necessary, an insulating layer (not shown) may be provided thereon to provide an MR effect, for example. Permalloy (N
i-F e-based alloy) or N i-F e-G o
Ferromagnetic thin films (11) and (12) consisting of gold w1 thin film of O-thread metal alloy on Ni system alloy
(13) For example, after depositing on the entire surface using A120v, this is patterned to form a magnetically sensitive portion (2) extending, for example, in a band shape.

The non-magnetic intermediate layer (13) consists of ferromagnetic thin II (11) and (
12) The ferromagnetic WtI5i1 (11) and (12), which are selected to have a thickness of several hundred Å or less so that the magnetostatic interaction acts more dominantly than the exchange interaction, are each If 100 people are selected, the total thickness of the magnetic sensing part (2) is formed to be, for example, about 800 people or more.

Incidentally, one of the two ferromagnetic thin F(11) and (12) is MR
It can be constructed by a ferromagnetic thin film having no or almost no effect, such as a high magnetic permeability@magnetic soft magnetic V\1 film such as Sendust, Go-based amorphous alloy + Mo permalloy. However, in this case, by selecting the saturation magnetic flux density, thickness, etc. of both thin films (11) and (12), the amount of magnetic flux of the thin films (11) and (12) is made to match, so that the magnetic flux is equal to that of the thin films (11) and (12). (11) and (12) can be closed as a whole to prevent generation of magnetic domains.

- An insulating layer (14) of 5hN4.5i02 or the like is deposited on the magnetically sensitive part (2), and electrode contact windows (14a) and (14b) are formed on both the front and rear ends of the magnetically sensitive part (2). )
are drilled, and these contact windows (14a) and (14
b) Through each front and rear electrode conductive layer (3)
and (4) are deposited, and further a bias magnetic field generating conductor (5) is applied across the magnetically sensitive part (2) via the insulating layer (14).
) is deposited. These electrode conductive layers (3) and (4) and the bias conductor (5) can be formed simultaneously by coating a metal layer such as Mo, W, 'I''5 etc. on the entire surface and patterning it by photolithography. These electrode conductors FJ (3) and 14) and the bias magnetic field generating conductor (5) are directed in a direction perpendicular to the extension direction of the magnetically sensitive part (2) (i.e., in the 111N direction of the sense current i with respect to this, Magnetically sensitive part (2) in the hard axis direction and in the direction perpendicular to the direction of application of the signal magnetic field from the magnetic recording medium.
extend on both sides of the At both ends of the bias magnetic field generating conductor (5), terminals t1 and 2 for passing a bias magnetic field generating current are drawn out as usual.

And each front and rear electrode conductive layer (3) and (4)
Both ends of each of the shielding magnetic material layers (7) are connected to each other in a loop shape so that % or a portion thereof is under the shielding magnetic material, f@ (7). 33) and (34) to terminals LSF and t
Derive sB.

Then, a shielding magnetic layer (7) made of permalloy, for example, having high magnetic permeability is placed on the arrangement part of the magnetically sensitive part (2) via an absolute #i layer (6) to a thickness of several μm by sputtering or plating. It is deposited to a certain thickness.

In this configuration, especially under the shield magnetic layer (7), each electrode conductor (31 and (4) and the bias magnetic field generating conductor (5) are parallel to each other, that is, the magnetic sensitive part (2
) extends linearly in the longitudinal direction, that is, in the direction perpendicular to the direction of conduction of the sense current i, the hard axis direction, and the direction of application of the signal magnetic field, and there are bends or edges throughout the extending direction. Make sure you have nothing to do.

That is, the edges of the electrode conductivity J@(31 and (4) on the opposite side from the terminal lead-out end side are made to exist outside the shield magnetic layer (7).And) Ji, 4fi (1)
The front end of the shield magnetic material layer (7) is polished to form a surface (8) that faces the magnetic recording medium and faces the front end surface of the magnetically sensitive portion (2).

In the example shown in FIG.
7) is the surface facing or facing the magnetic recording medium (8)
In some cases, the width at the front end facing the magnetic recording medium and the width at the rear end facing the magnetic recording medium are the same width, but in some cases, as shown in FIG. The width of the portion facing 8) may be narrower, although larger than the track width, and the width may be widened toward the rear, that is, the portion may have a shape that widens toward the rear.

Note that even when the shield magnetic layer (7) has a shape that widens toward the rear, as shown in FIG. 8, for example, the edges (4a) and (4b) of the rear electrode conductive layer (4) If it exists under body layer (7), it is shown in Figure 8 as 11.
As the magnetic domain structure is shown by lines, disturbance occurs in the 180" magnetic domain, which causes deterioration of the characteristics of the magnetic head. According to the present invention, these edges (4a) and (4b)
By preventing steps from occurring on the shield magnetic material layer (sword), 180° magnetic domains are generated in a relatively orderly manner,
This suppresses the generation of random magnetic domains in the shield magnetic layer.

〔Effect of the invention〕

As described above, according to the present invention, although the shield type MR magnetic head is configured, the upper shield magnetic layer (7) has at least the sense current i of the magnetically sensitive part (2), which is difficult to magnetize. Since the step extending in the axial direction and the direction along the direction of application of the signal magnetic field is avoided from occurring near the effective operating part of the magnetically sensitive part (2), the 180° magnetic domain is disturbed and this random magnetic domain is II: Unstable operation due to occurrence
! I'I&, and by adopting a configuration in which the sense current i is supplied to the magnetically sensitive part (2) in two parts from the magnetically sensitive part (2) to both sides, the electrode conductive layer ( By being able to alleviate the imbalance caused by the magnetic fields generated from 3) and (4), the characteristics can be further stabilized.

[Brief explanation of the drawing]

FIG. 1 is an enlarged plan view of an example of the magnetic head according to the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is an enlarged plan view of another example of the magnetic head of the present invention. 4 and 5 are an enlarged plan view of a conventional magnetic head and an enlarged sectional view taken along line A-A in FIG. 4, and FIGS. FIG. (1) is the substrate, (2) is the magnetic sensing part, (3) and (4) are the electrode 4''#j1 layer, (5) is the bias magnetic field generating conductor, (
7) is a shield magnetic layer.

Claims (1)

[Claims] A magnetically sensitive part has a ferromagnetic thin film having a magnetoresistive effect on a substrate, and a sense current is applied to both ends of the magnetically sensitive part in the same direction as a signal magnetic field, and a sense current is applied to the magnetically sensitive part in the same direction as a signal magnetic field. A pair of electrode conductive layers led out in a direction substantially perpendicular to the sense current direction and a bias magnetic field generating conductor extending across the magnetically sensitive section via an insulating layer, and an arrangement of the magnetically sensitive section. In a magnetoresistive magnetic head in which a shield magnetic layer is disposed over a portion of the magnetoresistive head, the electrode conductive layer and the bias magnetic field generating conductor are connected to the magnetically sensitive portion in the portion where the shield magnetic layer is disposed. The electrode conductive layers extend in a direction substantially perpendicular to the direction in which the signal magnetic field is applied, such that both ends of each of the electrode conductive layers are connected to each other outside the area where the shielding magnetic layer is arranged, or a part thereof is under the shielding magnetic layer. 1. A magnetoresistive magnetic head, characterized in that the loop portion has a loop shape, and terminals are led out from the loop portion.