U.S. patent application number 11/892890 was filed with the patent office on 2008-04-03 for magneto-resistance effect element, magnetic head, magnetic recording/reproducing device and magnetic memory.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Hiromi Fuke, Susumu Hashimoto, Hitoshi Iwasaki, Masayuki Takagishi.
Application Number | 20080080098 11/892890 |
Document ID | / |
Family ID | 39256230 |
Filed Date | 2008-04-03 |
United States Patent
Application |
20080080098 |
Kind Code |
A1 |
Fuke; Hiromi ; et
al. |
April 3, 2008 |
Magneto-resistance effect element, magnetic head, magnetic
recording/reproducing device and magnetic memory
Abstract
A magneto-resistance effect element includes: a first
magnetization layer of which a magnetization is substantially fixed
in one direction; a second magnetization layer of which a
magnetization is rotated in accordance with an external magnetic
field; an intermediate layer which contains insulating portions and
magnetic metallic portions and which is provided between the the
first magnetic layer and the second magnetic layer; and a pair of
electrodes to flow current in a direction perpendicular to a film
surface of a multilayered film made of the first magnetic layer,
the intermediate layer and the second magnetic layer; wherein the
magnetic metallic portions of the intermediate layer contain
non-ferromagnetic metal.
Inventors: |
Fuke; Hiromi; (Yokohama-shi,
JP) ; Hashimoto; Susumu; (Nerima-ku, JP) ;
Takagishi; Masayuki; (Kunitachi-shi, JP) ; Iwasaki;
Hitoshi; (Yokosuka-shi, JP) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
Kabushiki Kaisha Toshiba
Tokyo
JP
TDK Corporation
Tokyo
JP
|
Family ID: |
39256230 |
Appl. No.: |
11/892890 |
Filed: |
August 28, 2007 |
Current U.S.
Class: |
360/314 ;
G9B/5.117; G9B/5.139 |
Current CPC
Class: |
G11B 5/3983 20130101;
H01F 10/3259 20130101; G11B 5/3906 20130101; G11B 5/398 20130101;
G11C 11/161 20130101; B82Y 40/00 20130101; G01R 33/093 20130101;
B82Y 25/00 20130101; H01L 43/08 20130101; H01F 10/3272 20130101;
H01F 41/305 20130101 |
Class at
Publication: |
360/314 |
International
Class: |
G11B 5/33 20060101
G11B005/33 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2006 |
JP |
P2006-265836 |
Claims
1. A magneto-resistance effect element, comprising: a first
magnetization layer of which a magnetization is substantially fixed
in one direction; a second magnetization layer of which a
magnetization is rotated in accordance with an external magnetic
field; an intermediate layer which contains insulating portions and
magnetic metallic portions and which is provided between the said
first magnetic layer and said second magnetic layer; and a pair of
electrodes to flow current in a direction perpendicular to a film
surface of a multilayered film made of said first magnetic layer,
said intermediate layer and said second magnetic layer, wherein
said magnetic metallic portions of said intermediate layer contain
non-ferromagnetic metal.
2. The magneto-resistance effect element as set forth in claim 1,
wherein said non-ferromagnetic metal is at least one selected from
the group consisting of Cu, Cr, V, Ta, Nb, Sc, Ti, Mn, Zn, Ga, Ge,
Zr, Y, Tc, Re, B, In, C, Si, Sn, Ca, Sr, Ba, Au, Ag, Pd, Pt, Ir,
Rh, Ru, Os and Hf.
3. The magneto-resistance effect element as set forth in claim 2,
wherein said non-ferromagnetic metal contains at least Cu.
4. The magneto-resistance effect element as set forth in claim 1,
wherein said insulating portions of said intermediate layer contain
a compound containing at least one of oxygen, nitrogen and
carbon.
5. The magneto-resistance effect element as set forth in claim 1,
wherein said magnetic metallic portions of said intermediate layer
contain at least one of Fe, Co and Ni.
6. The magneto-resistance effect element as set forth in claim 1,
wherein said first magnetic layer and said second magnetic layer
contain at least one of Fe, Co and Ni.
7. The magneto-resistance effect element as set forth in claim 1,
wherein said intermediate layer suppresses an interlayer-coupling
between said first magnetic layer and said second magnetic
layer.
8. The magneto-resistance effect element as set forth in claim 1,
wherein in said intermediate layer, magnetic domain walls formed in
said magnetic metallic portions are narrowed to enhance an MR
effect of said magneto-resistance effect element.
9. A magnetic head comprising a magneto-resistance effect element
as set forth in claim 1.
10. A magnetic recording/reproducing device comprising a magnetic
recording medium and a magnetic head as set forth in claim 1.
11. A magnetic memory comprising a magneto-resistance effect
element as set forth in claim 1.
12. A method for manufacturing a magneto-resistance effect element,
comprising: forming a first magnetization layer of which a
magnetization is substantially fixed in one direction; forming a
first metallic layer as magnetic metallic portions on said first
magnetization layer; forming a second metallic layer on said first
metallic layer; applying energy enough to excite atoms onto said
second metallic layer and then, oxidizing said second metallic
layer to convert said second metallic layer into insulating
portions, thereby forming an intermediate layer which contains said
insulating portions and said magnetic metallic portions; forming a
second magnetization layer of which a magnetization is rotated in
accordance with an external magnetic field; and forming a pair of
electrodes to flow current in a direction perpendicular to a film
surface of a multilayered film made of said first magnetic layer,
said intermediate layer and said second magnetic layer.
13. A method for manufacturing a magneto-resistance effect element,
comprising: forming a first magnetization layer of which a
magnetization is substantially fixed in one direction; forming a
first metallic layer as magnetic metallic portions on said first
magnetization layer; forming a second metallic layer on said first
metallic layer; oxidizing said second metallic layer to convert
said second metallic layer into insulating portions and then,
applying energy enough to excite atoms onto said insulating
portions, thereby forming an intermediate layer which contains said
insulating portions and said magnetic metallic portions; forming a
second magnetization layer of which a magnetization is rotated in
accordance with an external magnetic field; and forming a pair of
electrodes to flow current in a direction perpendicular to a film
surface of a multilayered film made of said first magnetic layer,
said intermediate layer and said second magnetic layer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No.
2006-265836, filed on Sep. 28, 2006; the entire contents of which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a magneto-resistance effect
element which is configured such that a current is flowed in the
direction perpendicular to the film surface thereof. The present
invention also relates to a magnetic head, a magnetic
recording/reproducing device and a magnetic memory which utilize
the magneto-resistance effect element according to the present
invention.
[0004] 2. Description of the Related Art
[0005] Recently, the performance of a magnetic device, particularly
such as a magnetic head is enhanced by means of Giant
Magneto-Resistance Effect (GMR) made of a multilayered magnetic
structure. Particularly, since a spin valve film (SV film) can
exhibit a larger GMR effect, the SV film has developed the magnetic
device such as a magnetic head and MRAM (Magnetic Random Access
Memory).
[0006] The "spin valve" film has such a structure as sandwiching a
non-magnetic metal spacer layer between two ferromagnetic layers
and is configured such that the magnetization of one ferromagnetic
layer (often called as a "pinning layer" or "fixed magnetization
layer) is fixed by the magnetization of an anti-ferromagnetic layer
and the magnetization of the other ferromagnetic layer (often
called as a "free layer" or "free magnetization layer") is rotated
in accordance with an external magnetic field. With the spin valve
film, the large MR effect can be obtained by the variation of the
relative angle in magnetization between the pinned layer and the
free layer.
[0007] A conventional spin valve film is employed for a CIP
(Current In plane)-GMR element. In the CIP-GMR element, a sense
current is flowed to the SV film in the direction parallel to the
film surface thereof. Recently, attention is paid to a CPP (Current
Perpendicular to Plane)-GMR element and a TMR (Tunneling Magneto
Resistance) element because the CPP-GMR element and the TMR element
can exhibit the respective large MR effect in comparison with the
CIP element. In the CPP-GMR element and the TMR element, a sense
current is flowed to the SV film in the direction almost
perpendicular to the film surface thereof.
[0008] Recently, it was confirmed that a large MR effect with high
MR-ratio can be obtained from the minute coupling of Ni wires
(Reference 1).
[0009] Then, the minute magnetic coupling is formed
three-dimensionally so as to realize a magneto-resistance effect
element with high MR ratio (Reference 2). In this case, the
three-dimensional minute magnetic coupling is carried out by means
of EB (Electron beam) irradiation, FIB (Focused Ion beam)
irradiation or AFM (Atomic Force Microscope).
[0010] [Reference 1] Phys. Rev. Lett. 82 2923(1999)
[0011] [Reference 2] JP-A 2003-204095 (KOKAI)
[0012] It is considered that the MR effect as described above is
originated from the rapid variation in magnetization at the minute
magnetic coupling point. Namely, if the magnetic domain to be
formed at the minute magnetic coupling point is narrowed, the large
MR effect can be obtained. The magnetic domain can be indirectly
narrowed by decreasing the size (diameter) of the minute magnetic
coupling point (the size (diameter) of the ferromagnetic metallic
portion of the complex spacer layer). However, too small size of
the minute magnetic coupling point may increase the resistance
thereof excessively.
[0013] On the other hand, if the size of the minute magnetic
coupling point is enlarged, the resistance of the minute magnetic
coupling point can be reduced, but too large size of the minute
magnetic coupling point may strengthen the magnetic coupling
between the pinned layer and the free layer via the minute magnetic
coupling so as to increase the interlayer-coupling. The increase of
the interlayer-coupling causes undesirably the shift of the
operating point toward the higher magnetic field at the magnetic
head containing the minute magnetic coupling.
BRIEF SUMMARY OF THE INVENTION
[0014] It is an object of the present invention to provide a new
magneto-resistance effect element which can exhibit a larger MR
effect without the shift of operating point due to the low
resistance and the high interlayer-coupling.
[0015] In order to achieve the above object, an aspect of the
present invention relates to a magneto-resistance effect element,
comprising: a first magnetization layer of which a magnetization is
substantially fixed in one direction; a second magnetization layer
of which a magnetization is rotated in accordance with an external
magnetic field; an intermediate layer which contains insulating
portions and magnetic metallic portions and which is provided
between the first magnetic layer and the second magnetic layer; and
a pair of electrodes to flow current in a direction perpendicular
to a film surface of a multilayered film made of the first magnetic
layer, the intermediate layer and the second magnetic layer;
wherein the magnetic metallic portions of the intermediate layer
contain non-ferromagnetic metal.
[0016] The inventors had intensely studied to achieve the above
object. As a result, according to the aspect of the present
invention, an intermediate layer containing insulating portions and
magnetic metallic portions is provided between the first magnetic
layer and the second magnetic layer to cause the magnetic coupling
via the magnetic metallic portions of the intermediate layer. Then,
non-ferromagnetic metal is contained in the magnetic metallic
portions of the intermediate layer so that the magnetization of the
magnetic metallic portions can be reduced.
[0017] As a result, since the width of the magnetic wall, which is
formed in the magnetic metallic portion of the intermediate layer,
is decreased in the thickness direction, the resistance change
ratio, that is, the MR effect can be enhanced and the
interlayer-coupling between the first magnetic layer and the second
magnetic layer, which sandwich the intermediate layer, can be
suppressed. Particularly, even though the diameter of the minute
magnetic coupling point is increased so as to decrease the element
resistance, the interlayer-coupling can be reduced.
[0018] The non-ferromagnetic metal may be at least one selected
from the group consisting of Cu, Cr, V, Ta, Nb, Sc, Ti, Mn, Zn, Ga,
Ge, Zr, Y, Tc, Re, B, In, C, Si, Sn, Ca, Sr, Ba, Au, Ag, Pd, Pt,
Ir, Rh, Ru, Os and Hf. Particularly, the non-ferromagnetic metal
may contain at least Cu.
[0019] Similarly, the magnetic metallic portions of the
intermediate layer may contain at least one of Fe, Co and Ni. Also,
the first magnetic layer and the second magnetic layer may contain
at least one of Fe, Co and Ni.
[0020] According to the aspects of the present invention can be
provided a new magneto-resistance effect element which can exhibit
a larger MR effect without the shift of operating point due to the
low resistance and the high interlayer-coupling.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0021] FIG. 1 is a structural view illustrating an embodiment of
the magneto-resistance effect element according to the present
invention.
[0022] FIG. 2 is an explanatory view schematically showing the
cross sectional state of the magnetization of the
magneto-resistance effect element in FIG. 1 in the vicinity of the
intermediate layer thereof.
[0023] FIG. 3 is a graph showing the dependence of the resistance
change ratio AR with the external magnetic field H in the
magneto-resistance effect element in FIG. 1.
[0024] FIG. 4 is an explanatory view schematically showing the
cross sectional state of the magnetization of a magneto-resistance
effect element which is different from the magneto-resistance
effect element in FIG. 1 and which does not contain a
non-ferromagnetic portion in the ferromagnetic portion of the
intermediate layer thereof.
[0025] FIG. 5 is a graph showing the dependence of the resistance
change ratio .DELTA.R with the external magnetic field H in the
magneto-resistance effect element in FIG. 4.
[0026] FIG. 6 is a perspective view illustrating a magnetic
recording/reproducing device according to the present
invention.
[0027] FIG. 7 is a perspective view illustrating the magnetic head
assembly of the magnetic recording/reproducing device in FIG.
6.
[0028] FIG. 8 is a view illustrating a magnetic memory matrix
according to the present invention.
[0029] FIG. 9 is a view illustrating another magnetic memory matrix
according to the present invention.
[0030] FIG. 10 is a cross sectional view illustrating an essential
part of the magnetic memory.
[0031] FIG. 11 is a cross sectional view of the magnetic memory
illustrated in FIG. 10, taken on line "A-A".
DETAILED DESCRIPTION OF THE INVENTION
[0032] Hereinafter, the present invention will be described in
detail with reference to the drawings.
(Magneto-Resistance Effect Element)
[0033] FIG. 1 is a perspective view illustrating a
magneto-resistance effect element according to an embodiment of the
present invention. Some or all components throughout the drawings
in the present application are schematically illustrated so that
the illustrated sizes (thickness) and thickness ratio for the
components is different from the real sizes and thickness ratio for
the components.
[0034] The magneto-resistance effect element 10 illustrated in FIG.
1 includes a bottom electrode LE and a top electrode UE which are
disposed so as to sandwich a plurality of layers composing the
magneto-resistance effect element 10. Concretely, the
magneto-resistance effect element 10 is configured such that an
underlayer 11, an antiferromagnetic layer 12, a complex pinned
layer 13, an intermediate layer 14, a free layer 15 and a
protective layer 16 are subsequently formed on the bottom electrode
LE. The complex pinned layer 13 is configured such that a magnetic
anti-parallel coupling layer 132 is sandwiched between a first
pinned layer 131 and a second pinned layer 132. The intermediate
layer 14 is composed of insulating portions 141 and magnetic
metallic portions 142 which are disposed alternately in the
intermediate layer 14.
[0035] In this embodiment, the complex pinned layer 13, the
intermediate layer 14 and the free layer 15 constitute the spin
valve film.
[0036] The complex pinned layer 13 corresponds to a first magnetic
layer, as defined in claims, of which the magnetization is
substantially fixed in one direction, and the free layer 15
corresponds to a second magnetic layer, as defined in claims, of
which the magnetization is rotated in accordance with an external
magnetic field. The intermediate layer 14 corresponds to an
intermediate layer as defined in claims. The first magnetic layer
may be made of a single magnetic layer instead of a multilayered
structure such as the complex magnetic layer 13.
[0037] The bottom electrode LE and the top electrode UE function as
flowing a sense current to the magneto-resistance effect element 10
in the direction perpendicular to the film surface of the spin
valve film. As a result, the magneto-resistance effect element 10
constitutes a CPP (Current Perpendicular to Plane) type
magneto-resistance effect element configured such that the sense
current is flowed in the direction perpendicular to the film
surface of the element.
[0038] The underlayer 11 maybe formed as a two-layered structure of
a buffer layer and a seed layer, for example. The buffer layer can
relax the surface roughness of the bottom electrode LE and be made
of Ta, Ti, W, Zr, Hf, Cr or an alloy thereof. The seed layer
functions as controlling the crystalline orientation of the spin
valve film and be made of Ru,
(Fe.sub.xNi.sub.100-x).sub.100-yX.sub.y (X.dbd.Cr, V, Nb, Hf, Zr,
Mo; 15<x<25, 20<y<45).
[0039] The antiferromagnetic layer 12 may be made of
antiferromagnetic material (e.g., PtMn, PdPtMn, IrMn, RuRhMn) which
applies unidirectional anisotropy to the complex pinned layer 13 so
as to fix the magnetization of the complex pinned layer 13.
[0040] The first pinned layer 131 and the second pinned layer 132
of the complex pinned layer 13 may be made of, e.g., Fe, Co, Ni,
FeCo alloy or FeNi alloy. The magnetic anti-parallel coupling layer
132 functions as coupling in antiferromagnetism the first pinned
layer 131 and the second pinned layer 132 and may be made of Ru, Ir
or Rh.
[0041] The insulating portion 141 of the intermediate layer 14 may
be made of an oxide, a nitride, an oxynitride or a carbide
containing at least one selected from the group consisting of Al,
Mg, Li, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Se, Sr,
Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Sb, Ba, Ka, Hf, Ta, W, Re, Pt,
Hg, Pb, Bi and lanthanoid. The insulating portion 141 may be made
of another electrically insulating material.
[0042] The magnetic metallic portion 142 of the intermediate layer
14 functions as an electric current path to flow current
therethrough in the direction perpendicular to the film surface of
the intermediate layer 14 and may be made of single ferromagnetic
material such as Fe, Co, Ni or ferromagnetic alloy material. When a
magnetic field directed at the direction opposite to the direction
of the magnetization of the second pinned layer 132 is applied to
the free layer 15 so that the direction of the magnetization of the
free layer 15 is aligned in the direction of the magnetic field,
the direction of the magnetization of the second pinned layer 133
becomes anti-parallel to the direction of the magnetization of the
free layer 15. In this case, since the magnetic metallic portion
142 is sandwiched between the ferromagnetic layers (complex pinned
layer 13 and the free layer 15) with the respective different
directions of magnetization, a magnetic domain wall DW is formed in
the magnetic metallic portion 142.
[0043] In this embodiment, the diameter "d" of the magnetic
metallic portion 142 is not constant in the thickness direction as
shown in FIG. 1 (In FIG. 1, the top width of the metallic portion
142 becomes larger than the bottom width of the metallic portion
142). In this case, the typical diameter "d" can be defined by the
average diameter in thickness direction.
[0044] In this embodiment, non-ferromagnetic metal is incorporated
in the magnetic metallic portion 142 of the intermediate layer 14.
The non-ferromagnetic metal can be selected from the group
consisting of Cu, Cr, V, Ta, Nb, Sc, Ti, Mn, Zn, Ga, Ge, Zr, Y, Tc,
Re, B, In, C, Si, Sn, Ca, Sr, Ba, Au, Ag, Pd, Pt, Ir, Rh, Ru, Os,
Hf. Preferably, the non-magnetic metal is Cu. In this case, the
interlayer-coupling between the complex pinned layer 13 (second
pinned layer 133) and the free layer 15 can be suppressed even
though the diameter of the minute magnetic coupling point, that is,
the magnetic metallic portion 142 is enlarged so as to decrease the
resistance between the complex pinned layer 13 and the free layer
15.
[0045] The free layer (free magnetization layer) 15 may be made of
ferromagnetic material (e.g., Fe, Co, Ni, FeCo alloy, FeNi alloy)
so that the magnetization of the free layer 15 can be rotated in
accordance with an external magnetic field. In this embodiment, the
free layer 15 is formed as a single-layered structure, but may be
formed as a multilayered structure composed of a plurality of
layers stacked.
[0046] The protective layer 16 functions as protecting the spin
valve film. The protective layer 16 may be formed as a two-layered
structure of Cu/Ru or a three-layered structure of Cu/Ta/Ru.
[0047] FIG. 2 is an explanatory view schematically showing the
cross sectional state of the magnetization of the
magneto-resistance effect element 10 in the vicinity of the
intermediate layer 14. FIG. 3 is a graph showing the R--H
characteristic of the magneto-resistance effect element 10.
[0048] In the magneto-resistance effect element 10 of this
embodiment, as shown in FIG. 2, since the non-ferromagnetic metal
as described above is incorporated in the magnetic metallic portion
142 of the intermediate layer 14, the magnetization (Ms) of the
magnetic metallic portion 142 is reduced. Therefore, the
interlayer-coupling between the complex pinned layer 13 (second
pinned layer 133) and the free layer 15 can be suppressed and the
width of the magnetic domain wall DW, which is formed in the
magnetic metallic portion 142, is decreased in the thickness
direction so as to enhance the resistance change ratio, that is,
the MR effect.
[0049] In real, in the magneto-resistance effect element 10 of this
embodiment, as shown in FIG. 3, the shift of the R--H curve by the
external magnetic field, which is originated from the
interlayer-coupling, can not be almost recognized, and the
resistance change .DELTA.R becomes high.
[0050] FIG. 4 is an explanatory view schematically showing the
cross sectional state of the magnetization of a magneto-resistance
effect element which is different from the magneto-resistance
effect element 10 and which does not contain the non-ferromagnetic
metal in the magnetic metallic portion 142 of the intermediate
layer 14. FIG. 5 is a graph showing the R--H characteristic of the
magneto-resistance effect element in FIG. 4.
[0051] In the case that the non-ferromagnetic metal is not
incorporated in the magnetic metallic portion 142 of the
intermediate layer 14, the width of the magnetic domain wall DW in
the magnetic metallic portion 142 becomes almost equal to the
diameter of the magnetic domain wall DW and becomes larger than the
width of the insulating portion 141. Therefore, the
interlayer-coupling between the complex pinned layer 13 (second
pinned layer 133) and the free layer 15 is increased so as to
reduce the resistance change .DELTA.R.
[0052] In real, in the magneto-resistance effect element 10 of this
embodiment, as shown in FIG. 5, the shift of the R--H curve by the
external magnetic field, which is originated from the
interlayer-coupling, is observed, and the resistance change
.DELTA.R becomes low.
(Method for Manufacturing a Magneto-Resistance Effect Element)
[0053] Then, the method for manufacturing the magneto-resistance
effect element will be schematically described. First of all, on
the substrate are subsequently formed the bottom electrode LE, the
underlayer 11, the antiferromagnetic layer 12, the complex pinned
layer 13, the intermediate layer 14, the free layer 15, the
protective layer 16 and the top electrode UE. Normally, each layer
is formed under depressurized atmosphere. Hereinafter, the forming
process of each layer will be described.
(1) Formation of Bottom Electrode LE through Antiferromagnetic
Layer 12
[0054] The bottom electrode 11 is formed on the (not shown)
substrate by means of micro-process in advance. Then, the
underlayer 11 and the antiferromagnetic layer 12 are formed.
(2) Formation of Complex Pinned Layer 13
[0055] Then, the first pinned layer 131, the magnetic anti-parallel
coupling layer 132 and the second pinned layer 133 are subsequently
formed. In this case, a non-ferromagnetic metallic layer may be
formed on the second pinned layer 133. Also, an alloy layer made of
the material constituting the pinned layer and the material
constituting the non-ferromagnetic metallic layer may be formed on
the second pinned layer 133.
(3) Formation of Intermediate Layer 14
[0056] Then, the formation of the intermediate layer 14 will be
described. The intermediate layer 14 is composed of the insulating
portions 141 made of Al.sub.2O.sub.3 and the magnetic metallic
portions 142 made of a mixture of main Fe component and Cu
component added to the main Fe component.
[0057] First of all, the first metallic layer is formed on the
second pinned layer 133. The first metallic layer contains the main
Fe component as a supplier for the magnetic metallic layer 142 and
the Cu component. Then, the second metallic layer (e.g., Al), which
is to be converted into the insulating portions 141, is formed on
the first metallic layer. Then, ion beams of inert gas (e.g., Ar)
are irradiated onto the second metallic layer so that the
pre-treatment (ion treatment) can be carried out for the second
metallic layer. According to the ion treatment, the elements of the
first metallic layer are partially infiltrated into the second
metallic layer. Instead of the ion treatment, another energy
applying means may be employed. For example, the plasma treatment
or the thermal treatment can be exemplified, but the energy
applying means is not limited to the above-listed ones only if the
elements of the first metallic layer are partially infiltrated into
the second metallic layer.
[0058] Then, an oxidizing gas (e.g., an inert gas containing oxygen
gas) is supplied so that the second metallic layer can be oxidized
to form the insulating portions 141. In this case, the oxidizing
condition is determined so that some elements of the first metallic
layer infiltrated into the second metallic layer are unlikely to be
oxidized. According to the oxidizing treatment, the second metallic
layer is converted into the insulating portions made of
Al.sub.2O.sub.3, and the elements of the first metallic layer forms
the magnetic metallic portions 142.
[0059] Herein, the oxidizing method is not restricted only if the
magnetic metallic portions 142 are not oxidized and remains.
Concretely, ion beam oxidizing method, plasma oxidizing method or
ion assisted oxidizing method may be employed. Instead of the
oxidizing treatment, nitriding treatment or carbonizing treatment
can be employed.
[0060] The intermediate layer 14 can be formed as follows. First of
all, the first metallic layer as the supplier of the magnetic
metallic portions 142 is formed on or as the second pinned layer
133. Thereafter, the second metallic layer (e.g., Al) to be
converted into the insulating portions 141 is formed on the first
metallic layer. After the second metallic layer is formed, an
oxidizing gas (e.g., an inert gas containing oxygen gas) is
supplied so that the second metallic layer can be oxidized to form
the insulating layer. Concretely, ion beam oxidizing method, plasma
oxidizing method or ion assisted oxidizing method may be employed
as the oxidizing treatment. Instead of the oxidizing treatment,
nitriding treatment or carbonizing treatment can be employed.
[0061] Then, ion beams of inert gas (e.g., Ar) are irradiated onto
the insulating portions so that the post-treatment (ion treatment)
can be carried out for the insulating portions. According to the
ion treatment, the elements of the first metallic layer are
infiltrated into the insulating layer to form the intermediate
layer 14 containing the insulating portions 141 made of
Al.sub.2O.sub.3 and the magnetic metallic portions 142. Instead of
the ion treatment, the plasma treatment or the thermal treatment
may be employed.
(4) Formation of Free Layer 15, Protective Layer 16 and Top
Electrode UE
[0062] Then, the free layer 15 is formed on the intermediate layer
14, and the protective layer 16 and the top electrode UE are formed
on the free layer 15, thereby forming the magneto-resistance effect
element 10.
(5) Thermally Treatment
[0063] The magneto-resistance effect element 10 is thermally
treated under magnetic field so that the direction of the
magnetization of the first pinned layer 131 is fixed.
(Magnetic Head and Magnetic Recording/Reproducing Device)
[0064] The magneto-resistance effect element is installed in
advance in an all-in-one magnetic head assembly allowing both the
recording/reproducing, and mounted as the head assembly at the
magnetic recording/reproducing device.
[0065] FIG. 6 is a perspective view illustrating the schematic
structure of the magnetic recording/reproducing device. The
magnetic recording/reproducing device 150 illustrated in FIG. 6
constitutes a rotary actuator type magnetic recording/reproducing
device. In FIG. 6, a magnetic recording disk 200 is mounted to a
spindle 152 to be turned in the direction designated by the arrow A
by a motor (not shown) which is driven in response to control
signals from a drive unit controller (not shown). In FIG. 6, the
magnetic recording/reproducing apparatus 150 may be that provided
with a single magnetic recording disk 200, but with a plurality of
magnetic recording disks 200.
[0066] A head slider 153 recording/reproducing information to be
stored in the magnetic recording disk 200 is mounted on a tip of a
suspension 154 of a thin film type. The head slider 153 mounts at
the tip the magnetic head containing the magnetic resistance effect
element as described in above embodiments.
[0067] When the magnetic recording disk 200 is rotated, such a
surface (ABS) of the head slider 153 as being opposite to the
magnetic recording disk 200 is floated from on the main surface of
the magnetic recording disk 200. Alternatively, the slider may
constitute a so-called "contact running type" slider such that the
slider is in contact with the magnetic recording disk 200.
[0068] The suspension 154 is connected to one edge of the actuator
arm 155 with a bobbin portion supporting a driving coil (not shown)
and the like. A voice coil motor 156 being a kind of a linear motor
is provided at the other edge of the actuator arm 155. The voice
coil motor 156 is composed of the driving coil (not shown) wound
around the bobbin portion of the actuator arm 155 and a magnetic
circuit with a permanent magnet and a counter yoke which are
disposed opposite to one another so as to sandwich the driving
coil.
[0069] The actuator arm 155 is supported by ball bearings (not
shown) provided at the upper portion and the lower portion of the
spindle 157 so as to be rotated and slid freely by the voice coil
motor 156.
[0070] FIG. 7 is an enlarged perspective view illustrating a
portion of the magnetic head assembly positioned at the tip side
thereof from the actuator arm 155, as viewed from the side of the
magnetic recording disk 200. As illustrated in FIG. 7, the magnetic
head assembly 160 has the actuator arm 155 with the bobbin portion
supporting the driving coil and the like. The suspension 154 is
connected with the one edge of the actuator arm 155.
[0071] Then, the head slider 153 with the magnetic head containing
the magneto-resistance effect element as defined in
above-embodiments is attached to the tip of the suspension 154. The
suspension 154 includes a lead wire 164 for writing/reading
signals, where the lead wire 164 is electrically connected with the
respective electrodes of the magnetic head embedded in the head
slider 153. In the drawing, reference numeral "165" denotes an
electrode pad of the assembly 160.
[0072] In the magnetic recording/reproducing device illustrated in
FIGS. 6 and 7, since the magneto-resistance effect element as
described in the above embodiments is installed, the information
magnetically recorded in the magnetic recording disk 200 under
higher density recording than normal recording can be read out
properly.
(Magnetic Memory)
[0073] The magneto-resistance effect element as described above can
constitute a magnetic memory such as a magnetic random access
memory (MRAM) where memory cells are arranged in matrix.
[0074] FIG. 8 is a view illustrating an embodiment of the magnetic
memory matrix according to the present invention. This drawing
shows a circuit configuration when the memory cells are arranged in
an array. In order to select one bit in the array, a column decoder
350 and a line decoder 351 are provided, where a switching
transistor 330 is turned ON by a bit line 334 and a word line 332
and to be selected uniquely, so that the bit information recorded
in a magnetic recording layer (free layer) in the
magneto-resistance effect film 10 can be read out by being detected
by a sense amplifier 352. In order to write the bit information, a
writing current is flowed in a specific write word line 323 and a
bit line 322 to generate a magnetic field for writing.
[0075] FIG. 9 is a view illustrating another embodiment of the
magnetic memory matrix according to the present invention. In this
case, a bit line 322 and a word line 334 which are arranged in
matrix are selected by decoders 360, 361, respectively, so that a
specific memory cell in the array is selected. Each memory cell is
configured such that the magneto-resistance effect film 10 and a
diode D is connected in series. Here, the diode D plays a role of
preventing a sense current from detouring in the memory cell other
than the selected magneto-resistance effect film 10. A writing is
performed by a magnetic field generated by flowing the writing
current in the specific bit line 322 and the word line 323,
respectively.
[0076] FIG. 10 is a cross sectional view illustrating a substantial
portion of the magnetic memory in an embodiment according to the
present invention. FIG. 11 is a cross sectional view of the
magnetic memory illustrated in FIG. 10, taken on line "A-A". The
configuration shown in these drawings corresponds to a 1-bit memory
cell included in the magnetic memory shown in FIG. 8 or FIG. 9.
This memory cell includes a memory element part 311 and an address
selection transistor part 312.
[0077] The memory element part 311 includes the magneto-resistance
effect film 10 and a pair of wirings 322, 324 connected to the
magneto-resistance effect film 10. The magneto-resistance effect
film 10 is the magneto-resistance effect element (CCP-CPP element)
as described in the above embodiments.
[0078] Meanwhile, in the address selection transistor part 312, a
transistor 330 having connection therewith via a via 326 and an
embedded wiring 328 is provided. The transistor 330 performs
switching operations in accordance with voltages applied to a gate
332 to control the opening/closing of the current confining path
between the magneto-resistance effect film 10 and the wiring
334.
[0079] Further, below the magneto-resistance effect film 10, a
write wiring 323 is provided in the direction substantially
orthogonal to the wiring 322. These write wirings 322, 323 can be
formed of, for example, aluminum (Al), copper (Cu), tungsten (W),
tantalnum (Ta) or an alloy containing any of these elements.
[0080] In the memory cell of such a configuration, when writing bit
information into the magneto-resistance effect element 10, a
writing pulse current is flowed in the wirings 322, 323, and a
synthetic magnetic field induced by the writing current is applied
to appropriately invert the magnetization of a recording layer of
the magneto-resistance effect element 10.
[0081] Further, when reading out the bit information, a sense
current is flowed through the magneto-resistance effect element 10
including the magnetic recording layer and a lower electrode 324 to
measure a resistance value of or a fluctuation in the resistance
values of the magneto-resistance effect element 10.
[0082] The magnetic memory according to the embodiment can assure
writing and reading by surely controlling the magnetic domain of
the recording layer even though the cell is miniaturized in size,
with the use of the magneto-resistance effect element according to
the above-described embodiment.
EXAMPLES
[0083] The present invention will be described in detail in view of
Examples.
Example 1
[0084] Example 1 relating to the magneto-resistance effect element
10 will be described. In Example 1, the magneto-resistance effect
element 10 was formed as follows: [0085] Underlayer 11: Ta 5
nm/NiFeCr 7 nm [0086] Antiferromagnetic layer 12: PtMn 15 nm [0087]
First pinned layer 131: Co.sub.9Fe.sub.1 3.3 nm [0088] Magnetic
antiparallel coupling layer 132: Ru 0.9 nm [0089] Second pinned
layer 132: Fe.sub.5Co.sub.5 2.5 nm/Cu 0.1 nm
[0090] The underlayer 11 through the second pinned layer 132 were
subsequently formed. Then, the Al layer with a thickness of 0.9 nm
was formed and oxidized under Ar ion atmosphere. Then, the ion
treatment was carried out to form the multilayered structure of the
intermediate layer 14: the Al oxide/FeCo--Cu metallic layer. Then,
[0091] Free layer 15: Fe.sub.5Co.sub.5 2.5 nm [0092] Protective
layer 16: Cu 1 nm/Ta 2 nm/Ru 15 nm were formed.
[0093] The thus obtained magneto-resistance effect element 10 was
thermally treated at 270.degree. C. during ten hours under magnetic
field. As a result, in Example 1, the RA of the magneto-resistance
effect element 10 was 0.5 .OMEGA..mu.m.sup.2. Then, the MR value
was 200%, and the interlayer-coupling between the complex pinned
layer 133 and the free layer 15 was 20 Oe.
Example 2
[0094] Example 2 relating to the magneto-resistance effect element
10 will be described. In Example 2, the magneto-resistance effect
element 10 was formed as follows: [0095] Underlayer 11: Ta 5 nm/Ru
2 nm [0096] Antiferromagnetic layer 12: PtMn 15 nm [0097] First
pinned layer 131: Co.sub.9Fe.sub.1 3.3 nm [0098] Magnetic
antiparallel coupling layer 132: Ru 0.9 nm [0099] Second pinned
layer 132: Fe.sub.5Co.sub.5 2.5 nm/Cu 0.1 nm
[0100] The underlayer 11 through the second pinned layer 132 were
subsequently formed. Then, the Al layer with a thickness of 0.9 nm
was formed and oxidized under Ar ion atmosphere. Then, the ion
treatment was carried out to form the multilayered structure of the
intermediate layer 14: the Al oxide/FeCo--Cu metallic layer. Then,
[0101] Free layer 15: Fe.sub.5Co.sub.5 2.5 nm [0102] Protective
layer 16: Cu 1 nm/Ta 2 nm/Ru 15 nm were formed.
[0103] The thus obtained magneto-resistance effect element 10 was
thermally treated at 270.degree. C. during ten hours under magnetic
field. As a result, in Example 2, the RA of the magneto-resistance
effect element 10 was 0.3 .OMEGA..mu.m.sup.2. Then, the MR value
was 150%, and the interlayer-coupling between the complex pinned
layer 133 and the free layer 15 was 25 Oe.
Example 3
[0104] Example 3 relating to the magneto-resistance effect element
10 will be described. In Example 3, the magneto-resistance effect
element 10 was formed as follows: [0105] Underlayer 11: Ta 5
nm/NiFeCr 7 nm [0106] Antiferromagnetic layer 12: PtMn 15 nm [0107]
First pinned layer 131: Co.sub.9Fe.sub.1 3.3 nm [0108] Magnetic
antiparallel coupling layer 132: Ru 0.9 nm [0109] Second pinned
layer 132: Fe.sub.5Co.sub.5 2.5 nm/Zr 0.1 nm
[0110] The underlayer 11 through the second pinned layer 132 were
subsequently formed. Then, the Al layer with a thickness of 0.9 nm
was formed and oxidized under Ar ion atmosphere. Then, the ion
treatment was carried out to form the multilayered structure of the
intermediate layer 14: the Al oxide/FeCo--Zr metallic layer. Then,
[0111] Free layer 15: Fe.sub.5Co.sub.5 2.5 nm [0112] Protective
layer 16: Cu 1 nm/Ta 2 nm/Ru 15 nm were formed.
[0113] The thus obtained magneto-resistance effect element 10 was
thermally treated at 270.degree. C. during ten hours under magnetic
field. As a result, in Example 3, the RA of the magneto-resistance
effect element 10 was 0.5 .OMEGA..mu.m.sup.2. Then, the MR value
was 180%, and the interlayer-coupling between the complex pinned
layer 133 and the free layer 15 was 23 Oe.
Example 4
[0114] Example 4 relating to the magneto-resistance effect element
10 will be described. In Example 4, the magneto-resistance effect
element 10 was formed as follows: [0115] Underlayer 11: Ta 5 nm/Ru
2 nm [0116] Antiferromagnetic layer 12: PtMn 15 nm [0117] First
pinned layer 131: Co.sub.9Fe.sub.1 3.3 nm [0118] Magnetic
antiparallel coupling layer 132: Ru 0.9 nm [0119] Second pinned
layer 132: Fe.sub.5Co.sub.5 2.5 nm/Zr 0.1 nm
[0120] The underlayer 11 through the second pinned layer 132 were
subsequently formed. Then, the Al layer with a thickness of 0.9 nm
was formed and oxidized under Ar ion atmosphere. Then, the ion
treatment was carried out to form the multilayered structure of the
intermediate layer 14: the Al oxide/FeCo--Zr metallic layer. Then,
[0121] Free layer 15: Fe.sub.5Co.sub.5 2.5 nm [0122] Protective
layer 16: Cu 1 nm/Ta 2 nm/Ru 15 nm were formed.
[0123] The thus obtained magneto-resistance effect element 10 was
thermally treated at 270.degree. C. during ten hours under magnetic
field. As a result, in Example 4, the RA of the magneto-resistance
effect element 10 was 0.4 .OMEGA..mu.m.sup.2. Then, the MR value
was 120%, and the interlayer-coupling between the complex pinned
layer 133 and the free layer 15 was 28 Oe.
Example 5
[0124] Example 5 relating to the magneto-resistance effect element
10 will be described. In Example 5, the magneto-resistance effect
element 10 was formed as follows: [0125] Underlayer 11: Ta 5
nm/NiFeCr 7 nm [0126] Antiferromagnetic layer 12: PtMn 15 nm [0127]
First pinned layer 131: Co.sub.9Fe.sub.1 3.3 nm [0128] Magnetic
antiparallel coupling layer 132: Ru 0.9 nm [0129] Second pinned
layer 132: Fe.sub.5Co.sub.5 2.5 nm/Cu 0.2 nm
[0130] The underlayer 11 through the second pinned layer 132 were
subsequently formed. Then, the Al layer with a thickness of 0.9 nm
was formed and oxidized under Ar ion atmosphere. Then, the ion
treatment was carried out to form the multilayered structure of the
intermediate layer 14: the Al oxide/FeCo--Cu metallic layer. Then,
[0131] Free layer 15: Fe.sub.5Co.sub.5 2.5 nm [0132] Protective
layer 16: Cu 1 nm/Ta 2 nm/Ru 15 nm were formed.
[0133] The thus obtained magneto-resistance effect element 10 was
thermally treated at 270.degree. C. during ten hours under magnetic
field. As a result, in Example 5, the RA of the magneto-resistance
effect element 10 was 0.5 .OMEGA..mu.m.sup.2. Then, the MR value
was 220%, and the interlayer-coupling between the complex pinned
layer 133 and the free layer 15 was 15 Oe.
Example 6
[0134] Example 6 relating to the magneto-resistance effect element
10 will be described. In Example 6, the magneto-resistance effect
element 10 was formed as follows: [0135] Underlayer 11: Ta 5
nm/NiFeCr 7 nm [0136] Antiferromagnetic layer 12: PtMn 15 nm [0137]
First pinned layer 131: Co.sub.9Fe.sub.1 3.3 nm [0138] Magnetic
antiparallel coupling layer 132: Ru 0.9 nm [0139] Second pinned
layer 132: (Fe.sub.5CO.sub.5).sub.0.9Cu.sub.0.1 2.5 nm
[0140] The underlayer 11 through the second pinned layer 132 were
subsequently formed. Then, the Al layer with a thickness of 0.9 nm
was formed and oxidized under Ar ion atmosphere. Then, the ion
treatment was carried out to form the multilayered structure of the
intermediate layer 14: the Al oxide/FeCo--Cu metallic layer. Then,
[0141] Free layer 15: Fe.sub.5Co.sub.5 2.5 nm [0142] Protective
layer 16: Cu 1 nm/Ta 2 nm/Ru 15 nm were formed.
[0143] The thus obtained magneto-resistance effect element 10 was
thermally treated at 270.degree. C. during ten hours under magnetic
field. As a result, in Example 6, the RA of the magneto-resistance
effect element 10 was 0.5 .OMEGA..mu.m.sup.2. Then, the MR value
was 230%, and the interlayer-coupling between the complex pinned
layer 133 and the free layer 15 was 18 Oe.
[0144] In Examples, the second pinned layer 133 contains Cu or Zr,
but may contain another non-magnetic metal such as Cr, V, Ta, Nb,
Sc, Ti, Mn, Zn, Ga, Ge, Y, Tc, Re, B, In, C, Si, Sn, Ca, Sr, Ba,
Au, Ag, Pd, Pt, Ir, Rh, Ru, Os or Hf. In these cases using the
non-magnetic metal except Cu or Zr, the same effects as in Examples
were obtained. Namely, according to the magneto-resistance effect
element of to the present invention, the interlayer-coupling
between the complex pinned layer and the free layer can be
suppressed and the relatively large MR value can be obtained.
[0145] Although the present invention was described in detail with
reference to the above examples, this invention is not limited to
the above disclosure and every kind of variation and modification
may be made without departing from the scope of the present
invention.
[0146] In the application of the magneto-resistance effect element
to a reproducing magnetic head, if a top and bottom shields are
added to the magneto-resistance effect element, the detecting
resolution of the magnetic head can be defined.
[0147] Moreover, the magneto-resistance effect element can be
applied for both of a longitudinal magnetic recording type magnetic
head and a vertical magnetic recording type magnetic recording type
magnetic head. Also, the magneto-resistance effect element can be
applied for both of a longitudinal magnetic recording/reproducing
device and a vertical magnetic recording/reproducing device.
[0148] The magnetic recording/reproducing device may be a so-called
stationary type magnetic device where a specific recording medium
is installed therein or a so-called removable type magnetic device
where a recording medium can be replaced.
* * * * *