JP2001155312A - Magneto-resistive effect magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a Cu layer of a nonmagnetic metal thin film layer being a huge magneto-resistive effect layer from being degraded by electric migration and the Cu layer and a Co layer being a fixed layer from being corroded under a high humidity condition. SOLUTION: The nonmagnetic metal thin film layer being the huge magneto- resistive effect layer is formed from an alloy film of Cu and other metals or a multi-layered film of Cu and other metals. The fixed layer is formed from an alloy film obtained by adding a metal element other than Co and Fe as the third element to Co or a CoFe alloy. Each of the other metals and the metal element being the third element is at least one metal selected from the transition metals of Ag, Au, Pd, Pt, Rh, Ir, Ru, Ti, V, Cr, Zr and Nb.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used for a magnetic disk drive or a magnetic tape drive.
In particular, the present invention relates to a magneto-resistance effect type magnetic head for detecting a signal recorded on a magnetic recording medium by utilizing a giant magneto-resistance effect.

[0002]

2. Description of the Related Art Among magnetic heads used in magnetic disk drives and the like, a so-called giant magnetic field is observed especially in a multilayer film composed of a plurality of extremely thin soft magnetic films laminated with a non-magnetic metal thin film such as Cu interposed therebetween. A magneto-resistance effect type magnetic head utilizing the resistance effect has been disclosed in Japanese Unexamined Patent Publication No. 4-35831.
No. 0, a magnetoresistive layer having a first soft magnetic layer and a second soft magnetic layer laminated with a non-magnetic metal thin film interposed therebetween, and the second soft magnetic layer Controlling the magnetic domain structure of the antiferromagnetic layer continuously stacked to fix the magnetization of the body layer (called the fixed layer) and the first soft magnetic layer (called the free layer) of the magnetoresistive layer Magnetic domain control means, and further, an electrode for detecting a change in the magnetoresistance of the magnetoresistance effect layer by flowing a sense current to the magnetoresistance effect layer,
Is disclosed.

Further, in the conventional magnetoresistive magnetic head, a Cu layer,
That is, only a Cu layer is used, and a Co layer or C
It is specified that a soft magnetic layer such as an oFe alloy layer is used.

[0004]

In the above-described giant magnetoresistive magnetic head, in which a write-only electromagnetic induction type thin-film magnetic head is combined, as described above, the giant magnetoresistive layer is formed on the non-magnetic metal thin film layer. A Cu layer and a soft magnetic layer such as a Co layer or a CoFe alloy layer for the fixed layer are used.

On the other hand, in the magnetoresistive head, a sense current is applied to the giant magnetoresistive layer in order to reproduce a signal recorded on a magnetic recording medium, and the giant magnetoresistive layer is generated in response to a change in a signal magnetic field. A signal is reproduced by detecting a change in magnetoresistance of the resistance effect layer as a change in voltage. Here, the sense current is a constant current flowing through the fixed layer, the non-magnetic metal thin film layer, and the free layer.

For this reason, the magnitude of the reproduction output depends on the magnitude of the above-mentioned voltage change, and increases as the sense current increases, that is, as the sense current density in the giant magnetoresistive layer increases. However, the sense current density cannot be increased without limit, and there is a problem that the higher the current density, the higher the temperature due to Joule heat and the lower the output of the magnetic head due to electromigration.

[0007] In order to confirm this point, an actual energization test was conducted. As a result, the occurrence of electromigration in the Cu layer used as the nonmagnetic metal thin film layer was a major obstacle to an increase in sense current density. It became clear that. That is, when electromigration occurs in the Cu layer, the flow of electrons through the Cu layer from the fixed layer to the free layer and from the free layer to the fixed layer is hindered, and no change in magnetoresistance occurs and detection as a voltage change becomes impossible. is there.

On the other hand, when the magnetoresistive head is left in a relatively humid state, the output of some of the magnetic heads is reduced. This is due to the Cu layer of the nonmagnetic metal thin film layer. It has also been experimentally found that corrosion is caused in the Co layer of the fixed layer, and that the corrosion becomes a problem when the magnetoresistive head is used under high humidity conditions.

In the future, as the storage capacity of the magnetic disk device increases, the sense current density in the magnetoresistive layer of the magnetoresistive layer of the magnetoresistive effect type magnetic head tends to increase in order to increase the head output. Therefore, it is very important to increase the resistance to electromigration. At the same time, it is necessary to increase the reliability of the magnetic disk device in the use environment. Corrosion also occurs in the head manufacturing process and causes a reduction in yield, and if it occurs in the magnetic disk device, it becomes a serious problem in reliability. Therefore, solving the problem of corrosion is also a very important issue.

[0010] Against the above background, in the giant magnetoresistive head disclosed in the above-mentioned prior art, the output decreases due to the deterioration of the Cu layer due to electromigration, and the corrosion of the Cu layer and the Co layer under high humidity conditions. At present, no consideration is given to a decrease in output due to occurrence, and the like.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a high-output, high-reliability magnetoresistive head suitable for high-density magnetic recording and reproduction.

[0012]

In order to solve the above problems, the present invention employs the following configuration.

A giant magnetoresistive layer in which a fixed layer and a free layer are laminated with a pair of upper and lower magnetic shield layers, a nonmagnetic metal thin film layer interposed therebetween, and an antiferromagnetic layer continuously laminated on the giant magnetoresistive layer A magnetic domain control means for controlling a magnetic domain of the giant magnetoresistive layer, an electrode for detecting a change in magnetoresistance by passing a sense current through the giant magnetoresistive layer, A magnetoresistive head in which the nonmagnetic metal thin film layer in the giant magnetoresistive layer is formed from an alloy film of Cu and other metals or a multilayer film of Cu and other metals.

Also, a giant magnetoresistive layer in which a fixed layer and a free layer are laminated with a pair of upper and lower magnetic shield layers, a nonmagnetic metal thin film layer interposed therebetween, and an antiferromagnetic layer continuously laminated on the giant magnetoresistive layer A magnetoresistive magnetic head comprising: a body layer; magnetic domain control means for controlling magnetic domains of the giant magnetoresistive layer; and an electrode for detecting a change in magnetoresistance by passing a sense current through the giant magnetoresistive layer. The nonmagnetic metal thin film layer in the giant magnetoresistive layer is formed of an alloy film of Cu and other metals, or a multilayer film of Cu and other metals, and the fixed layer is formed of Co or a CoFe alloy.
A magnetoresistive magnetic head formed from an alloy film to which metal elements other than Co and Fe are added.

[0015] In the magnetoresistive head, the other metal in the non-magnetic metal thin film layer may be:
Ag, Au, Pd, Pt, Rh, Ir, Ru, Ti,
A magnetoresistive magnetic head selected from at least one of V, Cr, Zr, and Nb transition metals.

In the magneto-resistance effect type magnetic head, the metal element other than Co and Fe in the fixed layer may be Ag, Au, Pd, Pt, Rh, Ir, Ru, T
A magnetoresistive magnetic head selected from at least one of i, V, Cr, Zr, and Nb transition metals.

In the magnetoresistive head, the other metal in the non-magnetic metal thin film layer and the metal element other than Co and Fe in the fixed layer are Ag,
Au, Pd, Pt, Rh, Ir, Ru, Ti, V, C
A magneto-resistance effect type magnetic head selected from at least one of r, Zr, and Nb transition metals.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetoresistive head according to an embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a cross-sectional view of a magneto-resistance effect type magnetic head according to a first embodiment of the present invention as viewed from a medium facing surface side. In this embodiment, first, a lower magnetic shield layer 3 is formed on a substrate 1 made of an insulator such as alumina-titanium carbide via a base insulating layer 2 made of alumina or the like which is thickened for planarization. After laminating up to 4 μm and processing into a predetermined shape, an insulating layer 4 made of alumina or silica, or a mixture of both, for forming a lower gap
Are laminated in a thickness of 0.02 to 0.2 μm. These layers are all laminated by a sputtering method. In this embodiment, unless otherwise specified, an alumina film or a mixed film of alumina and silica is used as an insulating layer described below. However, there is no particular problem even if an insulating film other than alumina and silica is used.

After laminating the insulating layer 4 in this manner, a magnetoresistive layer 5 composed of a plurality of soft magnetic layers laminated with a nonmagnetic metal thin film layer therebetween, an antiferromagnetic layer 6, and a nonmagnetic layer The high-resistance conductor film 7 is continuously laminated by a sputtering method, and processed into a predetermined shape by photolithography and dry etching. Subsequently, the magnetic domain control permanent magnet film 8 and T
a / TaW or the like, a conductor layer 9 is also laminated by a sputtering method, and an electrode 10 having a predetermined shape is formed by a lift-off method to form an end of the pattern of the magnetoresistive layer 5, the antiferromagnetic layer 6, and the high-resistance conductor film 7. Formed in the part.

In this embodiment, the non-magnetic metal thin film layer 51 is formed of CuR as the magnetoresistive effect layer 5.
Using a u alloy film, Ta (54) / NiFe (52) /
CoFe (53) / CuRu (51) / Co layer (55)
The antiferromagnetic layer 6 uses a CrMnPt film, and the high-resistance conductor film 7 uses a Ta film.

At this time, the non-magnetic metal thin film layer 51 is made of C instead of the CuRu alloy film of the configuration example of the present embodiment.
u and Ag, Au, Pd, Pt, Rh, Ir, Ti, V,
An alloy film of at least one of the transition metals of Cr, Zr, and Nb may be used. Further, a multilayer film of Cu and the transition metal, for example, a multilayer film of Cu—Ag—Rh or Cu— There is no particular problem even if a multilayer film of Au-Cu-Au (in this case, the thickness of the multilayer film is desirably set to a substantially constant thickness regardless of the number of layers). The soft magnetic layer 52 of the magnetoresistive layer 5 is made of NiCo or N
An iFeCo film or the like is used as the antiferromagnetic layer 6 as MnPt.
It has been confirmed that a film or a NiFeMn film may be used without any problem.

Here, the NiFe (52) / CoFe film (53), which is the soft magnetic layer of the magnetoresistive layer 5, is a so-called free layer of the giant magnetoresistive layer, while the Co film 55 is a fixed layer. , Are stacked.

After forming up to the electrode 10 as described above, the insulating layer 11 for forming the upper gap is
Then, the upper magnetic shield layer and the lower magnetic pole 12 are stacked in a thickness of 1 to 4 μm, processed into a predetermined shape, and the fabrication of the read head unit 13 is completed. In order to actually use it as a recording / reproducing magnetic head, an insulating layer and a coil, an upper magnetic pole, and a protective insulating layer are sequentially formed on the upper magnetic shield layer and lower magnetic pole 12 to form a recording head portion. Then, the fabrication of the magnetoresistive head is completed.

In the magnetoresistive head according to the present embodiment, a signal is written to a magnetic recording medium in a recording head portion and the signal is read out in a reproducing head portion 13.
When reading the signal, it is necessary to supply a sense current for signal detection from the electrode 10 to the magnetoresistive layer 5. At this time, the direction of magnetization in the fixed layer 55 is fixed in the direction perpendicular to the medium facing surface by the antiferromagnetic layer 6, and the direction of magnetization in the free layers 52 and 53 is fixed to the fixed layer 55. It is desirable that the magnetization is controlled to be substantially perpendicular to the direction of magnetization.

When signal magnetic fields having different polarities are alternately applied to the magnetoresistive layer 5 from the magnetic recording medium, the magnetizations in the free layers 52 and 53 are rotated according to the signal magnetic field strength. In response to a change in the angle between the magnetization of the fixed layer and the magnetization of the free layer, the magnetoresistive layer 5
Resistance increases or decreases. The signal can be read out by detecting the change in magnetic resistance of the magnetoresistive layer 5 as a voltage change from the electrode 10. The voltage change, that is, the output of the head, increases as the sense current increases, as is clear from the operation principle just described.

The principle of operation of the magneto-resistance effect type magnetic head according to the present embodiment is as described above. In the case of the conventional head, when the detected current density flowing through the magneto-resistance effect layer increases, a phenomenon called electromigration occurs. As a result, the resistance of the magnetoresistive layer increases and the output of the head decreases, so that there is a problem that a sense current of a certain density or more cannot be passed.

However, according to the magnetoresistive head according to the present embodiment, as shown in FIG. 2, the detected current density of the magnetoresistive layer 5 is increased as compared with the conventional magnetoresistive head. However, it can be seen that the occurrence of electromigration is suppressed even when the sense current is increased, and the energization time until the resistance change of the magnetoresistive layer occurs is greatly increased. That is, according to the present embodiment (referred to as the head of the present embodiment in FIG. 2), there is an effect of extending the current-carrying life of the magnetoresistive head, and at the same time, the sense current density can be increased. It is clear that the head output is greatly enhanced.

FIG. 3 is a sectional view of a magnetoresistive head according to a second embodiment of the present invention, as viewed from the medium facing surface side. In this embodiment, CoRh is used as the fixed layer 55 in the magnetoresistive layer 5.
An alloy film is laminated (in place of the conventional Co layer or CoFe alloy layer), and CuRu is used as the nonmagnetic metal thin film layer 51.
Alloy films are laminated, and the other constituent materials and head structure of the head are the same as those of the magnetoresistive head of the first embodiment. Further, the operation principle of the magnetoresistive head is the same as that of the magnetoresistive head of the first embodiment, but Rh in the CoRh alloy film, which is a configuration example of the present embodiment, is set to A.
g, Au, Pd, Pt, Ir, Ru, Ti, V, Cr,
Even if at least one of the transition metals of Zr and Nb is replaced, Ru in the CuRu alloy film is changed to Ag or A.
u, Pd, Pt, Rh, Ir, Ti, V, Cr, Zr,
It has been confirmed that there is no particular problem even if at least one of the transition metals of Nb is replaced.

FIG. 4 shows the result of examining the effect of the magnetoresistive head according to the second embodiment (referred to as the head of this embodiment in FIG. 4) and comparing it with a conventional magnetoresistive head. FIG. 4 shows a comparison between the head output before and after the test when the magnetic head was left under high-temperature and high-humidity conditions. This shows the relationship with the test time (horizontal axis).

As shown in FIG. 4, in the conventional magneto-resistance effect type magnetic head, although the head output is reduced due to corrosion, the occurrence rate is about 1% after 100 hours. It can be seen that the type of magnetic head has a very low rate of corrosion, and hardly any head whose output decreases even under high temperature and high humidity conditions. According to the results shown in the figure, when a conventional magnetoresistive magnetic head is used in a magnetic recording device, corrosion may occur depending on the environment in which the device is used, and the output of the head may decrease. The magnetoresistive head has almost no possibility of this, and has the effect of greatly improving the reliability of the magnetic recording device.

As in the case of the first embodiment, the second embodiment has the effect of suppressing the occurrence of electromigration and greatly extending the conduction life of the magnetoresistive head. Obviously, since the sense current density can be increased, the head output can be greatly increased.

As described above, the embodiments of the present invention include those having the following configuration examples and functions.

First, the nonmagnetic metal thin film layer in the giant magnetoresistance effect layer is formed by an alloy film of Cu and another metal,
Alternatively, it is formed by a multilayer film of Cu and another metal film (for suppressing migration and preventing corrosion). Further, the fixed layer is formed of an alloy film in which a metal element other than Co and Fe is added as a third element to a Co or CoFe alloy (for corrosion prevention).

The other metals and the metal element as the third element are Ag, Au, Pd, Pt, R
h, Ir, Ru, Ti, V, Cr, Zr, and Nb.

The nonmagnetic metal thin film layer as described above is
The occurrence of migration is suppressed by adopting an improvement means applying u and other metals, and the improvement means applying Co or a CoFe alloy and a third element to the fixed layer, or the improvement of the nonmagnetic metal thin film layer By adopting the means, corrosion can be prevented. In other words, the occurrence of electromigration in the magnetoresistive magnetic head can be suppressed and the sense current can be increased. Can be suppressed. As a result, a high output of the head and a dramatic improvement in head reliability can be realized.

[0037]

According to the magnetoresistive head according to the present invention, as described above, the occurrence of electromigration in the giant magnetoresistive layer is suppressed, and the energization life of the magnetoresistive head is greatly extended. At the same time, there is an effect that the sense current density can be increased and the output of the head can be greatly increased.

On the other hand, in the case of the conventional magneto-resistance effect type magnetic head, corrosion may occur depending on the use environment of the magnetic recording device and the output of the head may be reduced. Corrosion does not occur in the magnetic head, and the reliability of the magnetic recording device using the magnetoresistive head is greatly improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a magnetoresistive head according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an effect of the magnetoresistive head of FIG. 1;

FIG. 3 is a cross-sectional view of a magneto-resistance effect type magnetic head according to a second embodiment of the present invention.

FIG. 4 is a diagram showing the effect of the magnetoresistive head of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Base insulating layer 3 Lower magnetic shield layer 4 Insulating layer 5 Magnetoresistive layer 6 Antiferromagnetic layer 7 High resistance conductor film 8 Permanent magnet film for magnetic domain control 9 Conductor layer 10 Electrode, 11 Insulating layer 12 Upper magnetic shield Layer / lower pole 13 Reproducing head 54 Ta layer 52, 53 Free layer 51 Non-magnetic metal thin film 55 Fixed layer

Claims (5)

[Claims] 1. A giant magnetoresistive layer in which a fixed layer and a free layer are laminated with a pair of upper and lower magnetic shield layers, a nonmagnetic metal thin film layer interposed therebetween, and an antiferromagnetic layer continuously laminated on the giant magnetoresistive layer. A magnetoresistive magnetic head comprising: a body layer; magnetic domain control means for controlling magnetic domains of the giant magnetoresistive layer; and an electrode for detecting a change in magnetoresistance by passing a sense current through the giant magnetoresistive layer. The non-magnetic metal thin film layer in the giant magnetoresistive layer is formed of an alloy film of Cu and other metals or a multilayer film of Cu and other metals. 2. A giant magnetoresistive layer in which a fixed layer and a free layer are stacked with a pair of upper and lower magnetic shield layers, a nonmagnetic metal thin film layer interposed therebetween, and an antiferromagnetism continuously stacked on the giant magnetoresistive layer. A magnetoresistive magnetic head comprising: a body layer; magnetic domain control means for controlling magnetic domains of the giant magnetoresistive layer; and an electrode for detecting a change in magnetoresistance by passing a sense current through the giant magnetoresistive layer. The nonmagnetic metal thin film layer in the giant magnetoresistive layer is formed from an alloy film of Cu and other metals, or a multilayer film of Cu and other metals, and the fixed layer is made of Co or CoFe alloy. A magnetoresistive magnetic head formed of an alloy film to which metal elements other than Co and Fe are added. 3. The magnetoresistive magnetic head according to claim 1, wherein the other metal in the nonmagnetic metal thin film layer is Ag,
Au, Pd, Pt, Rh, Ir, Ru, Ti, V, C
A magnetoresistive magnetic head selected from at least one of r, Zr, and Nb transition metals. 4. The magneto-resistance effect type magnetic head according to claim 2, wherein the metal element other than Co and Fe in the fixed layer is A.
g, Au, Pd, Pt, Rh, Ir, Ru, Ti, V,
A magnetoresistance effect type magnetic head selected from at least one of transition metals of Cr, Zr, and Nb. 5. The magneto-resistance effect type magnetic head according to claim 2, wherein the other metal in the non-magnetic metal thin film layer and the metal element other than Co and Fe in the fixed layer are Ag, Au,
Pd, Pt, Rh, Ir, Ru, Ti, V, Cr, Z
A magnetoresistance effect type magnetic head, wherein the magnetoresistance effect type magnetic head is selected from at least one of r and Nb transition metals.