Dynamic magnetic information storage or retrieval – Head – Magnetoresistive reproducing head
Reexamination Certificate
2001-08-01
2003-08-19
Heinz, A. J. (Department: 2653)
Dynamic magnetic information storage or retrieval
Head
Magnetoresistive reproducing head
C360S324120, C365S173000
Reexamination Certificate
active
06608738
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermally-stable magnetoresistance effect device, and to a magnetic head, a magnetic recording apparatus, and a magnetoresistance effect memory device using the thermally-stable magnetoresistance effect device.
2. Description of the Related Art
In recent years, in a magnetoresistance effect device including a layered structure of ferromagnetic layer (free layer)
on-magnetic layer/ferromagnetic layer (pinned layer), studies on GMR (giant magnetoresistance) devices which use a metal film, such as Cu or the like, in the non-magnetic layer, and studies on a tunneling-type magnetoresistance effect device, called a TMR device, which uses an insulative film, such as Al
2
O
3
or the like, in the non-magnetic layer, have become enthusiastic (Journal of Magnetism and Magnetic Materials, 139 (1995), L231). Application of the GMR device and the TMR device to a magnetic head and a memory device has been studied (2000 IEEE ISSCC TA7.2, TA7.3). There is already an application of the GMR device to a magnetic head. The TMR device exhibits a magnetoresistance change rate of about 40% at room temperature and is expected to achieve high output.
However, such a magnetoresistance effect device is a layered film having a thickness of several nanometers. At 250° C.-300° C. or higher, interfacial diffusion is caused in the magnetoresistance effect device, and characteristics of the magnetoresistance effect device deteriorate. Specifically, in a magnetoresistance effect device including an antiferromagnetic layer in which a pinned layer contains Mn, such as FeMn, IrMn, etc., and ferromagnetic layers which are exchange-coupled via the antiferromagnetic layer, at a temperature of 250° C. or higher, Mn is diffused, and as a result, characteristics of the magnetoresistance effect device deteriorate.
In order to eliminate such a problem, there is an attempt to form a pinned layer so as to have a structure, ferromagnetic layers
on-magnetic layer for exchange-coupling/ferromagnetic layers, wherein the two ferromagnetic layers are antiferromagnetically exchange-coupled via the non-magnetic layer for exchange-coupling containing Ru, Ir, Rh, etc. In such a structure, diffusion of Mn is prevented by Ru, Ir, Rh, etc.
However, in this case, the thickness of the non-magnetic layer for exchange-coupling is about 0.6-0.8 nm, and thus, at 300° C. or higher, diffusion is caused in an interface of the non-magnetic layer for exchange-coupling, whereby characteristics of such a magnetoresistance effect device deteriorate. That is, the above problem cannot be eliminated.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a magnetoresistance effect device includes: a free layer whose magnetization direction is easily rotated by an external magnetic field; a non-magnetization layer; and a pinned layer whose magnetization direction is not easily rotated by an external magnetic field, the pinned layer being provided on a face of the non-magnetization layer which is opposite to a face on which the free layer is formed, wherein the pinned layer includes: a first non-magnetic film for exchange-coupling; and first and second magnetic films which are antiferromagnetically exchange-coupled to each other via the first non-magnetic film, and the first non-magnetic film includes one of the oxides of Ru, Ir, Rh, and Re.
In one embodiment of the present invention, the magnetoresistance effect device is a tunneling-type magnetoresistance effect device.
In another embodiment of the present invention, the magnetoresistance effect device further includes an antiferromagnetic film which is magnetically exchange-coupled to the pinned layer.
In still another embodiment of the present invention, the free layer includes a second non-magnetic layer for exchange-coupling, and third and fourth magnetic films which are antiferromagnetically exchange-coupled to each other via the second non-magnetic film; the second non-magnetic film for exchange-coupling includes one of the oxides of Ru, Ir, Rh, and Re; and the third magnetic film has an intensity of magnetization M
1
and a thickness t
1
and the fourth magnetic film has an intensity of magnetization M
2
and a thickness t
2
, and a product (M
1
×t
1
) is substantially different from a product (M
2
×t
2
).
In still another embodiment of the present invention, at least one of the first through fourth magnetic films mainly contains cobalt (Co) and also contains boron (B).
In still another embodiment of the present invention, at least one of the first and second magnetic films mainly contains cobalt (Co) and also contains boron (B).
In still another embodiment of the present invention, the magnetoresistance effect device further includes: an antiferromagnetic layer which is magnetically exchange-coupled to the pinned layer; and an underlying layer mainly containing NiFeCr, the underlying layer being provided on a face of the antiferromagnetic layer which is opposite to a face on which the pinned layer is formed.
According to another aspect of the present invention, a magnetoresistance effect device includes: a free layer whose magnetization direction is easily rotated by an external magnetic field; a non-magnetization layer; and a pinned layer whose magnetization direction is not easily rotated by an external magnetic field, the pinned layer being provided on a face of the non-magnetization layer which is opposite to a face on which the free layer is formed, wherein the free layer includes: a first non-magnetic layer for exchange-coupling; and first and second magnetic films which are antiferromagnetically exchange-coupled to each other via the first non-magnetic film, the first non-magnetic film includes one of the oxides of Ru, Ir, Rh, and Re, and the first magnetic film has an intensity of magnetization M
1
and a thickness t
1
and the second magnetic film has an intensity of magnetization M
2
and a thickness t
2
, and a product (M
1
×t
1
) is substantially different from a product (M
2
×t
2
).
In one embodiment of the present invention, the magnetoresistance effect device is a tunneling-type magnetoresistance effect device.
In another embodiment of the present invention, the magnetoresistance effect device further includes: an antiferromagnetic layer which is magnetically exchange-coupled to the pinned layer; and an underlying layer mainly containing NiFeCr, the underlying layer being provided on a face of the antiferromagnetic layer which is opposite to a face on which the pinned layer is formed.
According to still another aspect of the present invention, a magnetic head for detecting a signal magnetic field from a recording medium includes: two shield sections each including a magnetic substance; and the magnetoresistance effect device of the present invention provided in a gap between the two shield sections.
According to still another aspect of the present invention, a magnetic head includes: a magnetic flux guiding section including a magnetic substance; and the magnetoresistance effect device of the present invention for detecting a signal magnetic field introduced by the magnetic flux guiding section.
According to still another aspect of the present invention, a magnetic recording medium includes: the magnetic head of the present invention for recording a signal in a recording medium; an arm on which the magnetic head is mounted; a driving section for driving the arm; and a signal processing section for processing the signal and supplying the processed signal to the magnetic head.
According to still another aspect of the present invention, a magnetoresistance effect memory device includes: a magnetoresistance effect device including a free layer whose magnetization direction is easily rotated by an external magnetic field, a non-magnetization layer, and a pinned layer whose magnetization direction is not easily rotated by an external magnetic field, the pinned layer being provided on a face of the non-magnetization layer which is opposite to a face on
Kawawake Yasuhiro
Sakakima Hiroshi
Sugita Yasunari
Heinz A. J.
Matsushita Electric - Industrial Co., Ltd.
Renner Otto Boisselle & Sklar
LandOfFree
MAGNETORESISTANCE EFFECT DEVICE UTILIZING AN OXIDE FILM TO... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with MAGNETORESISTANCE EFFECT DEVICE UTILIZING AN OXIDE FILM TO..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and MAGNETORESISTANCE EFFECT DEVICE UTILIZING AN OXIDE FILM TO... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3079766