JPH01116912A - Magneto-resistance effect type magnetic head - Google Patents

Abstract

PURPOSE:To evade the formation a random magnetic domain and unstable operation by leading out an electrode conductive layer for a magnetic sensing part almost at right angles to the sense current direction of the magnetism sensing part and extending this electrode conductive layer out of a shield magnetic body. CONSTITUTION:A main operation part in front of and nearby the magnetism sensing part 2 on a contact or facing surface 8 for a magnetic recording medium is extended almost without any edge or bent part over nearly the entire range of the arrangement part of magnetic material layer 7 in the application direction of a signal magnetic field from the magnetic recording medium, i.e. hard-to- magnetize axis direction and therefore at right angles to the feeding direction of a sense current, in other words, in the easy-to-magnetize axis direction. A shield magnetic material layer 7 has no step, so the formation of a random magnetic domain is evaded, the characteristics of the magnetism sensing part 2 is stabilized, and the error rate of a reproducing device is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetoresistive magnetic head, particularly a shielded magnetoresistive magnetic head.

[A essential point of the invention]

The present invention provides a shield type magnetoresistive magnetic helad in which a magnetic sensing part having a magnetoresistive effect is provided on a substrate, and a shielding magnetic layer is arranged to cover this magnetic sensing part. The electrode conductivity j- for this magnetically sensitive part is derived in a direction substantially perpendicular to the direction of the sense current in the part, and this electrode conductive layer is extended outside the shielding magnetic body to prevent the shielding magnetic body from the edge of the electrode conductive layer. To avoid deterioration of head output due to unstable magnetic domain operation by minimizing disturbance of magnetic domains due to layer steps.

[Conventional technology]

In a magnetoresistive magnetic head (hereinafter referred to as MR type magnetic head), the magnetically sensitive FI1%, that is, the magnetoresistive effect (hereinafter referred to as MR effect) element is stacked with two sheets of SDR or SDR having an MR effect laminated with an insulating layer interposed therebetween. For example, an MR type magnetic head is constructed of four to one layers of magnetic thin films, one of which has an MR effect and the other of which has no or almost no MR effect, and a sense current is passed in the same direction through both wi films. JP-A-61-182620, JP-A-62-5
This method is disclosed in Japanese Patent Application No. 2711 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.

In such an MR type magnetic head, at least one side has an MR effect on the substrate (1), as shown in FIG. 7, which is an enlarged plan view, and FIG. first and second ferromagnetic thin films (11) and (12) having
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 which faces this surface (8). This magnetically sensitive part (
2) Above or below, a direction that extends in the rack width direction and is perpendicular to the track width direction with respect to the magnetic sensing portion (2). Conductor for generating a bias magnetic field (5) for applying a bias magnetic field in the direction (in the direction of application of the signal magnetic field to the magnetically sensitive part (2)) to operate within the range where the magnetoresistance characteristics in the magnetically sensitive part (2) have linearity.
are laminated with a surface insulating JMI (14) interposed therebetween. On the other hand, the front end and the rear end of the magnetically sensitive part (2) are provided with a magnetic recording medium in a direction substantially perpendicular to the facing surface (8) or facing the magnetic recording medium with respect to the magnetically sensitive part (2). The front and rear electrode conductive layers (3) and (4) serve to apply a sense current i along the direction of the signal magnetic field obtained from the
) are deposited, and ferromagnetic thin E(11) and (12
) is selected so that the direction of the axis of difficult magnetization is along the direction of the signal magnetic field and the direction in which the sense current i flows. 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, while a magnetic material such as permalloy (N A sputtered or plated shielding magnetic material (7) is disposed with a thickness of several microns (i-Fe alloy).

When such a shielded MR type magnetic head configuration is adopted, the magnetic head characteristics may exhibit unstable characteristics.

[Problem that the invention seeks to solve]

The present invention aims to solve the above-mentioned problem of instability of characteristics in the shield type MR magnetic head.

That is, in the present invention, such a problem is solved as the seventh problem.
Upper shield magnetic body 1-(71
We will investigate what is caused by the magnetic domain state, and based on this investigation, we will create a configuration that stabilizes the magnetic domain state and state to solve the above-mentioned problems.

That is, in the shielded MR magnetic head described above, as shown in FIG. The layer (3) has an uneven surface due to the presence of the gradient. That is, in the above structure, the magnetically sensitive part (2) has a relatively thin total thickness of, for example, about 800 or more. Even if the edge of the bias magnetic field generating conductor (7) is under the shielding magnetic layer (7), the difference in level does not pose much of a problem.
5) and the electrode conductive layers (3) and (4) have a fairly large thickness, for example, 3,000 layers, in order to ensure their electrical reliability, that is, to avoid the occurrence of wire breakage, and to reduce the risk of pile damage. These bias magnetic field generating conductor (5) and electrode conductive layer (3)
If the edges of (4) and (4) exist under the shielding magnetic material layer (7), the shielding magnetic material layer (7) is placed through the insulating layer (6).
Despite being deposited and formed, the step at the edge becomes relatively large, and the shielding magnetic layer (7
) becomes noticeable.

Now, for example, if we look at the magnetic domain state when the shield magnetic material layer (7) is formed as a flat surface, the main magnetic domain extends in the direction of the easy axis of magnetization, as shown in Fig. 9 by the chain line. 18 arranged in parallel in almost one direction
It has a 0° magnetic domain configuration. Incidentally, the thickness of the shield magnetic layer (7) in this case is several micrometers, and the magnetostriction is 10''
It is considered to be on the order of "' and almost zero magnetostriction. However, as shown in FIG. 4) exists as shown in the dashed line in Fig. 10, the bending due to the step caused by the edges of these conductors <5) and the electrode conductive layers (3) and (4) causes the bending to occur as shown in the broken line in Fig. 10. A random magnetic domain exists in the 180° magnetic domain due to distortion or disturbance.The disturbance of this magnetic domain is particularly noticeable in the magnetically sensitive area (
If you live near 2), the unstable magnetic domain operation will have a large effect on the magnetoresistive characteristics of the magnetically sensitive part (2), which will immediately lead to a deterioration of the head output and cause errors in the magnetic recording and reproducing system. This results in a deterioration of the rate.

The generation of random magnetic domains does not have a large effect on the generation of random magnetic domains when the shield magnetic layer (7) is bent due to a step along the domain wall direction of the 180° magnetic domain, but it does have a large effect on the generation of random magnetic domains in the direction orthogonal to this. affect. In other words, 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. Furthermore, when the rear electrically conductive layer (4) is extended rearward in the direction of extension of the magnetically sensitive part (2), the difference in level between the left and right edges (4a) and (4b) is shown in FIG. As shown in FIG.
greatly affects. Further, for example, if the front electrode conductive layer (3) and the bias conductor 15) have a bent part in the pattern under the shield magnetic layer (1), a step corresponding to the bent shape causes a 180° magnetic domain distortion, that is, a random magnetic domain. has a major impact on the occurrence of

In particular, this random magnetic domain is generated near the surface (8) of the magnetic sensing part (2) in contact with the magnetic recording medium, that is, on the side where the signal magnetic field from the magnetic recording medium is introduced, that is, in the magnetic sensing part (2). It has a big impact on the main operating parts.

In the present invention, based on such research, the generation of random magnetic domains and unstable operation in the shield magnetic layer that affect the magnetically sensitive portion are avoided.

[Means for solving problems]

In the present invention, FIG. 1 shows a plan view, and FIG.
As shown in the cross-sectional view taken along the line A-A in the figure, a pair of ferromagnetic thin films (11) and (12), at least one of which has a magnetoresistive effect, is formed on the substrate +1 via a non-magnetic intermediate layer (13). A sense current 1 is applied in the same direction as the signal magnetic field from both ends of the laminated magnetically sensitive part (2), and is almost orthogonal to the direction of the sense current 1 in this magnetically sensitive part (2). It has electrode conductive layers (3) and (4) led out in the direction of However, in an MR type magnetic head in which a shielding magnetic layer (7) is arranged to cover the area where the magnetically sensitive part (2) is arranged, the electrode conductive layers (3) and (4) and the shielding magnetic layer (7) are used for generating a bias magnetic field. Under the arrangement of the shielding magnetic layer (7), the conductor (5) operates almost throughout the entire area, especially in the vicinity of the front side of the magnetically sensitive part (2) facing the magnetic recording medium or on the opposing surface (8). In this case, the direction in which the signal magnetic field is applied from the magnetic recording medium, that is, the direction perpendicular to the direction of the hard magnetization axis and the current direction of the sense current, in other words, the direction of the easy magnetization axis, is determined by the arrangement of the magnetic layer (7). The structure is such that it extends over almost the entire area with almost no edges or bent parts.

1 and 2, parts corresponding to those in FIGS. 7 and 8 are denoted 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.

〔Example〕

An example of the present invention will be further explained in detail with reference to FIGS. 1 and 2. The substrate (1) may be made 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, for example, an MR effect. Permalloy (N i
-Fe alloy) or Ni-Fe-Co alloy,
A ferromagnetic thin film (1
1) and (12) as a non-magnetic insulating intermediate layer (13) such as A
After evaporating 120 g over the entire surface, this is patterned to form, for example, a magnetically sensitive portion (2) extending in a strip shape.

The non-magnetic intermediate layer (13) consists of ferromagnetic thin films (11) and (1).
2) A thickness of several hundred angstroms or less is selected so that magnetostatic interaction acts more dominantly than exchange interaction. The ferromagnetic thin films (11) and (12) are each selected to have a thickness of several hundred, so that the total thickness of the magnetically sensitive portion (2) is, for example, about 800 or less.

one of the two ferromagnetic thin films (11) and (12) is MR
A ferromagnetic i-film having no or almost no effect may be constructed of a high permeability ferromagnetic soft magnetic thin film such as Sendust, Co thread amorphous alloy, Mo permalloy, etc. However, in this case, both thin films (11) and (1
2) By selecting the saturation magnetic flux density, thickness, etc., the amount of magnetic flux in both thin films (11) and (12) is made to match, and the magnetic flux is The structure is designed such that it can be closed automatically to prevent the generation of magnetic domains.

An insulating layer (14) such as Sigh4+ 5i (h) is formed 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 (
The front and rear electrode conductive layers (3) and (4) are deposited through the insulating Fit (14b), respectively.
) A conductor (5) for generating a bias magnetic field is deposited across the magnetic sensing part (2). These electrode conductive layers (3) and (4) and the bias conductor (5) can be formed simultaneously by depositing a metal layer such as MO, W, Ti, etc. over the entire surface and patterning it by photolithography. The bridge conductive layers (3) and (4) and the bias magnetic field generating conductor (5) are arranged in a direction perpendicular to the direction of extension of the magnetically sensitive part (2) (i.e., the direction in which the sense current i is applied with respect to this direction is difficult). The magnetically sensitive portion (2) is made to extend on both sides of the magnetically sensitive portion (2) in the axial direction and in the direction orthogonal to the direction in which the signal magnetic field is applied from the magnetic recording medium. Both ends of the bias magnetic field generating conductor (5) are connected to a terminal t1 for passing a bias magnetic field generating current.
and L2 are derived in the usual manner, but the electrode conductive layers (3) and (4) are connected from both ends or one end of each, for example, as shown in the figure, the sense current is supplied from the other end of each of the left and right ends. Each terminal LSF and tSB are derived.

A shielding magnetic material 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 insulating layer (6) by sputtering or plating to a thickness of several micrometers. is formed by adhering to it.

In this configuration, especially under the shield magnetic layer (7), each electrode conductive layer (3) and (4) and the bias magnetic field generating conductor (5) are arranged parallel to each other, that is, in the longitudinal direction of the magnetically sensitive part (2), that is, the sense Current direction of current i, difficult axis direction,
It is made to extend linearly in a direction perpendicular to the direction in which the signal magnetic field is applied, so that no bends or edges exist over the entire area in this extending direction.

That is, the edges of the electrode conductive layers (3) and (4) on the side opposite to the terminal lead-out end side are made to exist outside the shield magnetic layer (7). Then, the front end of the shield magnetic material layer (7) from the substrate (1) is polished so that the front end face of the magnetically sensitive part (2) faces the magnetic recording medium (
8) is formed.

In the example shown in FIG. 1, the shield magnetic layer (
? ) faces or faces 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.

In addition, in the pattern shown in FIG. 1, the terminals are led out from one end of each of the front and rear electrode conductive layers (3) and (4), but in some cases, these electrode conductive layers (1tit) (Both ends of each of 31 and (4) are connected to each other in a loop shape so that the shield magnetic material t* +7> outside or a part of it exists under the shield magnetic material N(7). From the loop section to the terminal tsF
It is also possible to derive tse and tse.

In addition, in the above example, a single magnetically sensitive part (2) is provided, but for example, as shown in FIG. 4, a pair of magnetically sensitive parts (
2), and the rear electrode conductive layer (4) can be led out from the rear end side of each pair of magnetically sensitive parts (2). In this case, a discontinuity, that is, an edge may occur between the pair of rear electrode conductive layers, which may cause a step or bend in the shield magnetic layer (7). Even if some disturbance of the magnetic domain occurs due to the existence of the magnetically sensitive part (2)
This can be tolerated because the effect on the effective operating part is small.

Furthermore, the present invention can also be applied to a structure in which an MR type magnetic head and an inductive type recording magnetic head are stacked in the same magnetic head. A top view of an example of this case is shown in FIG.
A cross-sectional view taken along line -A is shown in FIG. In FIGS. 5 and 6, parts corresponding to those in FIGS. 1 and 2 are given the same reference numerals and redundant explanations are omitted. In this case, the upper shield magnetic layer (7) is of an inductive type. For example, a spiral conductive pattern forming a head ring (32) of the inductive magnetic head is formed on the rear flat part of the shielding magnetic layer (7), which can also serve as one core of the recording magnetic head element. Form. Then, on top of this, the other core (33) having the required width that defines the track width of the inductive magnetic head is covered with an insulating layer (34).
Adhesion is formed through. The front end of this core (33) is a non-magnetic insulator that forms a spacer with a magnetic gap g on the surface (8) facing or facing the magnetic medium) if (
31), and the rear end is a window (34) bored in the insulating Jim (34) at the center of the wire ring (32).
connected to the shield magnetic layer (7) through a), a closed magnetic path is formed by the core (33) and the shield magnetic layer (7), and an inductive type recording head including a coil (32) is formed. . One terminal tR1 is led out from the outer end of the coil (32), and an insulating layer (3
The conductive layer (35) for leading out the terminal is torn through the holes 4) and 8 (34b), and the other terminal tR2 is led out from this.

In this case, the width of the shield magnetic layer (7) in the track width direction facing the magnetic recording medium or facing surface (8) is selected to be larger than the track width, but narrower than the rear side. In other words, it is desirable to have a shape that widens toward the rear, and by making the width narrower in the front direction, the shielding magnetic layer (7) makes it possible to reduce the width of the portion facing the magnetic recording medium or facing the opposing surface (8). By making the width small, it is possible to reduce the probability of an accident of peeling in this part, and the rear part is a flat surface, where the head wire ring (32) can be attached. Therefore, the occurrence of accidents such as breakage of the wire ring can be effectively avoided.

Incidentally, even when the shield magnetic layer (7) is shaped to spread out toward the rear, this causes disturbances, for example, in the edge (4a) and the magnetic domain of the rear electrode conductive layer (4), as shown in FIG. This causes deterioration of the characteristics of the magnetic head, but according to the present invention, these edges (4a) and (
4b) etc. are prevented from occurring in the shield magnetic layer (7), 180'' magnetic domains are generated in a relatively orderly manner, thereby suppressing the generation of random magnetic domains in the shield magnetic layer.

(Effects of the Invention) As described above, according to the present invention, although the shield type MR magnetic head structure is adopted, the upper shield magnetic layer (7) at least protects the magnetic sensing part (2) from sensing. current 1lI
The step extending in the direction of the et-conversion difficult axis and the direction in which the signal magnetic field is applied is avoided from occurring in the vicinity of the effective operating part of the magnetically sensitive part (2), so the 180° magnetic domain is disturbed and this Disturbance of magnetization in the magnetically sensitive portion 12) due to the generation of random magnetic domains, that is, unstable operation, is avoided, thereby making it possible to construct a stable MR magnetic head.

[Brief explanation of the drawing]

FIG. 1 is an enlarged plan view of an example of the magnetic head according to the present invention, and FIG.
4 and 4 are respectively enlarged plan views of other examples of the magnetic head of the present invention, FIG. 5 is an enlarged plan view of another example of the magnetic head according to the present invention, and FIG. Enlarged cross-sectional view,
7 and 8 are an enlarged plan view of a conventional magnetic head and an enlarged sectional view taken along line A-A in FIG. 7, and FIGS. 9 to 11 are explanations of magnetic domains in the shield magnetic layer. It is a diagram. (1) is the substrate, (2) is the magnetic sensing part, (3) and (4) are the electrode conductive layers, (5) is the bias magnetic field generating conductor, (7)
is a shielding magnetic layer.

Claims (1)

[Claims] A magnetically sensitive part is formed by laminating a pair of ferromagnetic thin films, at least one of which has a magnetoresistive effect, on a substrate with a nonmagnetic intermediate layer interposed therebetween, and a sense current is applied from both ends of the magnetically sensitive part in the same direction as the signal magnetic field. an electrode conductive layer that is applied in a direction substantially perpendicular to the sense current direction in the magnetically sensitive section, and a conductor for generating a bias magnetic field that extends across the magnetically sensitive section via an insulating layer; In the magnetoresistive magnetic head in which a shielding magnetic layer is disposed covering a part of the magnetically sensitive part, the electrode conductive layer and the bias magnetic field generating conductor are arranged in the area where the shielding magnetic layer is disposed. The electrode conductive layer and the bias magnetic field generating conductor are arranged so as to extend in a direction substantially perpendicular to the direction in which the signal magnetic field is applied to the magnetically sensitive part, and extend outside the area where the shield magnetic layer is arranged. A magnetoresistive magnetic head characterized by: