JP2001273760A - Magnetic memory and recording method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obviate the difficulty in the higher-scale integration of elements if current wires are arranged on one side or both sides of the elements with a magnetic memory using the megaro-magneto-resistive elements and tunnel magneto-resistive elements using perpendicularly magnetized films. SOLUTION: The upper parts or lower parts of the current wires 12 and 16 are provided with layers 11 and 17 consisting of high permeable magnetic materials and the elements at cross points are subjected to recording by the current wires arranged in the upper and lower parts of the extreme adjacent elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic memory using a magnetoresistive element composed of a magnetic layer having perpendicular magnetic anisotropy and a recording method thereof.

[0002]

2. Description of the Related Art A giant magnetoresistive (GMR) element or a tunnel magnetoresistive (TMR) element obtained by laminating a magnetic magnetic layer and a nonmagnetic layer is a conventional anisotropic magnetoresistive (AM) element.
R) High performance can be expected as a magnetic sensor because it has a larger magnetoresistance change rate than the element.

The GMR element has already been put to practical use as a reproducing magnetic head for a hard disk drive (HDD). On the other hand, since the TMR element has a higher magnetoresistance ratio than the GMR element, application to not only a magnetic head but also a magnetic memory is considered.

FIG. 1 shows an example disclosed in Japanese Patent Application Laid-Open No. 9-106514 as a basic configuration example of a conventional TMR element.
0 is shown.

[0005] As shown in FIG.
Magnetic layer 101, insulating layer 102, second magnetic layer 103,
The antiferromagnetic layer 104 is stacked. Here, the first
The magnetic layer 101 and the second magnetic layer 103 of Fe, C
a ferromagnetic material composed of o, Ni, or an alloy thereof;
The antiferromagnetic layer 104 is made of FeMn, NiMn, or the like, and the insulating layer 102 is made of Al ₂ O ₃ .

When the insulating layer 102 in FIG. 10 is replaced with a nonmagnetic layer having conductivity such as Cu, a GMR element is obtained.

In conventional GMR elements and TMR elements,
Since the magnetization of the magnetic layer portion is in the in-plane direction, when the element size is reduced as in a magnetic head having a narrow track width or a highly integrated magnetic memory, the magnetic field is strongly affected by a demagnetizing field generated at an end magnetic pole. . For this reason, the magnetization direction of the magnetic layer becomes unstable, and it becomes difficult to maintain uniform magnetization, which causes a malfunction of the magnetic head and the magnetic memory.

As a method for solving this problem, a magnetoresistive element using a magnetic layer having perpendicular magnetic anisotropy is disclosed in Japanese Unexamined Patent Publication No. Hei.
It is disclosed in Japanese Patent Application Laid-Open No. 1-213650. FIG. 11 shows the element structure of this publication.

In FIG. 11, a magnetoresistive element has a first magnetic layer 11 composed of a perpendicular magnetization film having a low coercive force.
1 and a second magnetic layer 113 made of a perpendicular magnetization film having a high coercive force. The first magnetic layer and the second magnetic layer have a ferrimagnetic film of a rare earth-transition element alloy, a garnet film,
Co, PdCo, or the like is used.

In this case, since the end magnetic poles are formed on the surface of the magnetic film, an increase in the demagnetizing field due to miniaturization of the element can be suppressed. Therefore, if the perpendicular magnetic anisotropy energy of the magnetic film is sufficiently larger than the demagnetizing field energy by the end pole, the magnetization can be stabilized in the vertical direction regardless of the dimensions of the element.

On the other hand, a recording method for a magnetic memory using a perpendicular magnetization film will be described with reference to a method disclosed in Japanese Patent Application Laid-Open No. 11-213650. FIG. 12 shows the arrangement of the magnetoresistive element and the write line in the publication.

The structure of the device shown in FIG. 12 is similar to that of FIG.
It is composed of a magnetic layer 121, a non-magnetic layer 122, and a second magnetic layer 123. When the first magnetic layer 121 is a memory layer, information is recorded on the element by applying current to recording current lines 124 and 125 provided on both sides of the element, and by a magnetic field generated from the current line. This is performed by reversing the magnetization of the first magnetic layer 121. For example, when the direction of magnetization of the first magnetic layer 121 is desired to be above the element, the recording current line 124 is used.
A current is caused to flow upward in the drawing, and to the recording current line 125 downward in the drawing. Since the combined component of the magnetic field generated from these two current lines is above the element, the magnetization of the first magnetic layer 121 can be arranged above the element.

[0013]

However, if the recording current line is arranged beside the magnetoresistive element, it is disadvantageous for high integration of the element. When the recording current lines are arranged on both sides of the element as shown in FIG. 12, the distance between adjacent elements is 4F when the wiring rule (F) is used. On the other hand, in a normal arrangement pattern in which a recording current line does not exist between elements, the distance between adjacent elements is 2F. In consideration of the importance of high integration of elements in memory creation, the magnetic memory shown in FIG. 12 is disadvantageous for high integration of elements.

Further, in the wiring pattern shown in FIG. 12, the information is not recorded on the element located at the side of the selected element, but is located in the depth direction of the selected element (upward or downward on the paper). Recording is performed on the element that performs the recording.
As a result, it is not possible to select the cross points of the elements arranged in a matrix.

In view of the above problems, the present invention provides a magnetic memory and a recording method which have a higher degree of integration than before and can record information at cross points of elements arranged in a matrix.

[0016]

The first invention of the present invention comprises at least a first magnetic layer, a non-magnetic layer, and a second magnetic layer, wherein the first and second magnetic layers are perpendicular magnetic layers. A magnetic memory using a magnetoresistive element having anisotropy, wherein a layer made of a high magnetic permeability material is laminated on a current line for recording information on the magnetoresistive element, and the current line is A magnetic memory, wherein the magnetic memory is arranged on upper and lower planes of an effect element.

According to a second aspect of the present invention, there is provided a magnetoresistive effect comprising at least a first magnetic layer, a nonmagnetic layer, and a second magnetic layer, wherein the first and second magnetic layers have perpendicular magnetic anisotropy. A method for recording a magnetic memory, comprising laminating a layer made of a high magnetic permeability material on an element and recording information by current lines arranged on upper and lower planes of the magnetoresistive element.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

<Embodiment 1> FIG. 1 shows a schematic configuration diagram of a magnetic memory according to the present embodiment. The magnetic memory according to the present embodiment includes a magnetoresistive element including a magnetic layer 13, a nonmagnetic layer 14, and a magnetic layer 15, and current lines 12 and 16 disposed above or below the element.

The current line 12 located above the element
And a lower portion of the current line 16 located below the element, are provided with high permeability layers 11 and 17, respectively. By providing the high magnetic permeability layers 11 and 17 above or below the current lines 12 and 16, the magnetic field generated from the current lines is concentrated on the recording layer of the magnetoresistive element, and efficient recording is performed. be able to.

In the magnetic memory of this embodiment, the nearest neighbor element interval is 2F using the minimum wiring rule F. In a magnetic memory in which a recording current line is arranged beside a device as in the prior art, the distance between the devices is reduced to half compared to the case where the space between adjacent devices is 4F. This means that the realization has been realized.

The current lines 12 and 16 are made of a conductive non-magnetic material such as Al or Cu, and have a high magnetic permeability layer 11 or 1 provided above the current line 12 or below the current line 16.
As a material of No. 7, NiFe, CoZrNb, or the like is used.

First magnetic layer 12 and second magnetic layer 14
Are rare earth metals (RE) and iron group transition metals (T
M) An amorphous alloy perpendicular magnetic film or a crystalline alloy perpendicular magnetic film such as a CoCr alloy.

When the first magnetic layer 13 is a recording layer, the first magnetic layer has a coercive force Hc capable of reversing magnetization by a magnetic field generated from the current line, and has a perpendicular magnetic anisotropy. Need to be. As a material of the first magnetic layer 13 satisfying such characteristics, a rare earth-transition metal binary alloy (CeC) containing a light rare earth metal such as Ce or Pr is used.
o, PrCo) or a ternary alloy composed of the above-mentioned light rare earth metal-heavy rare earth metal-transition metal (PrGdFe, P
rGdCo, PrTbFe, PrTbCo, PrFeC
o etc.).

On the other hand, the second magnetic layer 15 needs to have a coercive force of such a magnitude that the magnetization is not sufficiently reversed by the magnetic field generated from the current line while maintaining the perpendicular magnetic anisotropy. Materials suitable for the second magnetic layer 15 satisfying such characteristics include mainly rare earth metals such as Tb,
Binary alloys composed of heavy rare earth metals such as Gd and transition metals (T
bFe, TbCo, GdFe, GdCo, etc.) or a ternary alloy composed of heavy rare earth metal-transition metal (GdTbF
e, GdTbCo, TbFeCo, etc.)
Ferromagnetic materials having perpendicular magnetic anisotropy, such as r and CoPt, may be mentioned.

The thickness of the first and second magnetic layers is desirably 50 ° or more in consideration of superparamagnetism by thinning and 5000 ° or less in consideration of difficulty in fine processing by thickening.

The non-magnetic layer 14 may be made of a conductive non-magnetic material such as Cu used in a conventional GMR element, or an Al ₂ O ₃ film used in a TMR element. Considering the danger of the rare earth metal of the magnetic layer being oxidized, the insulating nonmagnetic layer may be made of AlN,
Nitride film such as BN, or Si, diamond, D
It is desirable to use an insulating film having a covalent bond such as LC (diamond-like carbon).

In the case of a TMR element, if the thickness of the non-magnetic layer is less than 5 °, there is a possibility that an electrical short circuit may occur between the magnetic layers, and if the thickness is more than 30 °, Since the electron tunneling phenomenon is less likely to occur, the angle is preferably 5 ° or more and 30 ° or less. On the other hand, in the case of the GMR element, when the film thickness is large, the element resistance becomes too small and the magnetoresistance change rate is also reduced.

Although not shown in the figure, an insulating film is provided between the current line and the magnetoresistive element to prevent the current line from being connected to the magnetoresistive element. This is necessary, for example, to prevent the current flowing through the magnetic thin film element from leaking to the recording current line at the time of reproduction to prevent the reproduction signal from deteriorating.

Next, the arrangement of the elements and the arrangement of the current lines will be described with reference to FIG. In this embodiment, an element processed into a cylindrical shape is used in order to stably maintain the magnetization state inside the magnetic layer.

As described above, the magnetoresistance effect elements 21 to 2
5 and the current lines 26a to 27c exist on different planes. Here, the current lines 26a, 26b, 26c exist on the upper plane of the elements 24, 22, 25, respectively, and the current lines 2
7a, 27b and 27c are elements 21, 22, and 23, respectively.
Exists on the lower plane of.

A method for selecting the elements 22 existing at the cross points when the elements are arranged in a matrix as shown in FIG. 2 will be described.

An electric current is applied to the recording current lines 26a and 26c to select an element in the column direction. However, it is not possible to select the element in the row direction only by this (element 2
1, 22, and 23 are all selected), so that the cross point 22 can be selected by applying a current to the other recording current lines 27a and 27c.

As described with reference to FIG. 1, the upper portion of the recording current lines 26a, 26b, 26c or the current line 27
Below the layers a, 27b and 27c, a layer made of a high magnetic permeability material is provided.

As shown in FIG. 3, in a magnetoresistive effect element including a first magnetic layer 31, a nonmagnetic layer 32, and a second magnetic layer 33, a recording layer representing magnetization information of "0" and "1". Is recorded according to whether the magnetization direction of the recording layer (first magnetic layer 31) is either (a) upward or (b) downward.

On the other hand, when reading recorded information, "0" or "1" is identified by a difference in resistance value depending on the relative direction of magnetization of the first magnetic layer 31 and the second magnetic layer 33. .
That is, when the magnetization directions of the first magnetic layer 31 and the second magnetic layer 33 are parallel as shown in FIG. The first magnetic layer 31 and the second
When the direction of magnetization of the magnetic layer 33 is antiparallel, a high resistance value is exhibited.

Next, the details of the recording method according to the present invention will be described with reference to FIGS.

Recording on the magnetoresistive effect element of the present invention is performed by using a current line 43 disposed above the elements (44 to 46) shown in FIG.
a and 43b, or the elements shown in FIG.
5) This is performed by using a composite component of the magnetic field generated from the current lines 56a and 56c arranged below.

Here, currents flow in the current lines 43a and 43b, and in the current lines 56a and 56b in opposite directions.

The magnetic field generated from the current line 43a and the current line 43b or the current line 56a and the current line 56b is applied to the high magnetic permeability layer (42a, 42a,
42c, 57a, 57c) form an ellipse.

When a high magnetic permeability material is disposed above or below the current line, the magnetic field generated from the current line is shielded on the high magnetic permeability layer side. Therefore, the magnetic field around the current line becomes asymmetric, and a stronger magnetic field is applied to the element side. As a result, it is possible to efficiently reverse the magnetization of the recording layer as compared with the case where the high magnetic permeability material is not provided.

Here, the recording method in the case where the magnetization directions of the recording layers 44 and 53 of the magnetoresistive element are directed to the upper side of the element is shown. 4 and FIG. 5, the recording current line 43a, the current line 43b, the current line 56a,
The direction of the current flowing through the current line 56b may be reversed.

When the element is used as a magnetic memory, a current line for reading is required. The current line for reading needs to be connected to the upper and lower parts of the element, and wiring can be provided separately from the current line for recording. However, by connecting the current line for recording to the element, the current line for recording It is also possible to double as a current line.

On the other hand, when the device is used as a magnetic memory, a structure in which the element is stacked on a transistor has been considered. In this case, the transistor must be connected to the lower part of the element. Therefore, when the element is stacked on the transistor, the recording current line above the element can also serve as the reading current line, but the recording current line below the element exists independently.

<Embodiment 2> FIG. 6 shows a schematic configuration diagram of a magnetic memory according to the present embodiment. The magnetic memory according to the present embodiment is located on a plane different from the magnetoresistive effect element including the magnetic layer 63 / nonmagnetic layer 64 / magnetic layer 65, and is disposed between the element and an adjacent element. It consists of current lines 62 and 66.

High magnetic permeability layers 61 and 67 are provided above the current line 62 located above the magnetoresistive element and below the current line 66 located below the element, respectively. By providing the high magnetic permeability layers 61 and 67 above or below the current lines 62 and 66, the magnetic field generated from the current lines is concentrated on the recording layer of the magnetoresistive element, and efficient recording is performed. be able to.

In the magnetic memory of the present invention, as in the case of the first embodiment, the nearest neighbor element interval is set to 2 using the minimum wiring rule F.
F, and in the case of this embodiment, the distance between the elements is reduced to half in comparison with the adjacent element interval 4F in the prior art.

Next, the element arrangement and the arrangement of the recording current lines will be described with reference to FIG. In this embodiment, in order to stably maintain the magnetization state inside the magnetic layer, an element processed into a cylindrical shape as in the first embodiment is used.

As shown in FIG. 6, as shown in FIG.
1 to 75 and the recording current lines 76 to 79 exist on different planes. Here, the recording current lines 76 and 77 are
75, and the current line 76 is
And 74, and the current line 77 is equidistant from the elements 72 and 75. On the other hand, the current lines 78 and 79
75, the current line 78 is equidistant from the elements 71 and 72, and the current line 79 is equidistant from the elements 72 and 73.

A method of selecting the elements 72 present at the cross points when the elements are arranged in a matrix as shown in FIG. 7 will be described.

A current is supplied to the current lines 76 and 77 to select an element in the column direction. However, it is not possible to select an element in the row direction only by this (elements 71, 72, 73).
Are selected), the other recording current line 7
8 and 79, the cross point 72
Can be selected.

As described with reference to FIG. 6, a layer made of a high magnetic permeability material is provided above the recording current lines 76 and 77 or below the current lines 78 and 79.

The element structure in this embodiment and the materials used for the magnetic memory are the same as those in the first embodiment.

FIG. 8 shows details of the recording method in this embodiment.
This will be described with reference to FIG. Recording on the magnetoresistive effect element of the present invention is performed by using a recording current line 8 arranged above the element shown in FIG.
3, or by using a composite component of a magnetic field generated from the recording current line 96 arranged below the element shown in FIG. Here, currents flow in opposite directions in adjacent current lines.

The magnetic field generated from the recording current line 83 or 96 becomes elliptical due to the high magnetic permeability layer provided above or below the current line. When the high magnetic permeability material is disposed above or below the recording current line, the magnetic field generated from the recording current line is shielded on the high magnetic permeability layer side. Therefore, the magnetic field around the current line becomes asymmetric, and a stronger magnetic field is applied to the element side. As a result, it is possible to efficiently reverse the magnetization of the recording layer as compared with the case where the high magnetic permeability material is not provided.

Here, the recording method in the case where the magnetization directions of the recording layers 84 and 93 of the magnetoresistive element are directed to the upper side of the element is shown. The direction of the current flowing through the recording current lines 83 and 96 in FIGS. 8 and 9 may be reversed.

When the element is used as a magnetic memory, a current line for reading is required. The current line for reading needs to be connected to the upper and lower parts of the element, and wiring can be provided separately from the current line for recording. However, by connecting the current line for recording to the element, the current line for recording It is also possible to double as a current line.

On the other hand, when using as a magnetic memory, a structure in which the element is stacked on a transistor has been considered. In this case, the transistor must be connected to the lower part of the element. Therefore, when the element is stacked on the transistor, the recording current line above the element can also serve as the reading current line, but the recording current line below the element exists independently.

[0059]

As described above, according to the present invention, it is possible to provide a magnetic memory having a higher degree of integration and higher efficiency of recording than before, and a method of recording on the magnetic memory.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a magnetic memory according to a first embodiment.

FIG. 2 is a diagram showing an arrangement diagram of a magnetoresistive element and a current line in Example 1.

FIG. 3 is a diagram showing magnetization states of “0” and “1” in a magnetoresistance effect element.

FIG. 4 is a diagram illustrating a recording method according to the first embodiment.

FIG. 5 is a diagram illustrating a recording method according to the first embodiment.

FIG. 6 is a schematic structural diagram of a magnetic memory according to a second embodiment.

FIG. 7 is a diagram showing a layout diagram of a magnetoresistive element and a current line in Example 2.

FIG. 8 is a diagram illustrating a recording method according to a second embodiment.

FIG. 9 is a diagram illustrating a recording method according to a second embodiment.

FIG. 10 is a diagram showing a conventional magnetoresistance effect element.

FIG. 11 is a view showing a conventional magnetoresistance effect element.

FIG. 12 is a diagram showing a conventional recording method for a magnetoresistive element.

[Explanation of symbols]

11, 17, 42a to 42c, 48, 51, 57a to 5
7c, 61, 67, 81, 88, 91, 98
High permeability layer 12, 16, 26a-26c, 27a-27c, 43a
To 43c, 47, 52, 56a to 56c, 62, 66,
76 to 79, 83, 87, 92, 96 Current lines for recording 13, 31, 44, 53, 63, 84, 93
First magnetic layers 14, 32, 45, 54, 64, 85, 94,
Non-magnetic layer 15, 33, 46, 55, 65, 86, 95
Second magnetic layer 21-25, 71-75
Magnetoresistance effect element 41, 58, 82, 97
Generated magnetic field

Continued on the front page (72) Inventor Shoji Michishima 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 5F083 FZ10 GA09 JA36 JA37

Claims (2)

[Claims] 1. A magnetic device comprising a magnetoresistive element comprising at least a first magnetic layer, a nonmagnetic layer, and a second magnetic layer, wherein the first and second magnetic layers have perpendicular magnetic anisotropy. A memory, wherein a layer made of a high magnetic permeability material is laminated on a current line for recording information on the magnetoresistive element, and the current lines are arranged on upper and lower planes of the magnetoresistive element. Magnetic memory. 2. A high-permeability magnetoresistive element comprising at least a first magnetic layer, a nonmagnetic layer, and a second magnetic layer, wherein the first and second magnetic layers have perpendicular magnetic anisotropy. A recording method for a magnetic memory, comprising laminating layers made of a magnetic susceptibility material, and recording information by current lines arranged on upper and lower planes of the magnetoresistive element.