JP2002353417A - Magnetoresistive effect element and magnetic memory device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To match the center of an operating point, when the magnetizing direction of the free layer of a magnetoresistive effect element is inverted to a zero magnetic field by removing its influence, even when Neel-coupling magnetic field is generated. SOLUTION: The magnetoresistive effect element 10 comprises the free layer 11 made of at least a ferromagnetic material, a nonmagnetic layer 12 made of a nonmagnetic material, and a laminated fixed layer 13 made of the ferromagnetic material. The element 10 is used for a magnetic memory device, in which information is recorded by utilizing the change of the magnetizing direction of the layer 11. In the element 10, an antiferromagnetic layer 15 made of an antiferromagnetic material is provided at the side of the layer 11, in which the layer 13 11 is not laminated, and the free layer 11 is connected to the layer 15 via a second nonmagnetic layer 16 made of the nonmagnetic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called MR (Ma
The present invention relates to a magnetoresistive element that generates a gnetoResistive effect and a magnetic memory device configured as a memory device that stores information using the magnetoresistive element.

[0002]

2. Description of the Related Art In recent years, an MRAM (Magnetic Rando) has been used as one of magnetic memory devices functioning as a memory device.
m Access Memory) has been proposed. The MRAM is a Giant Magnetoresistive (GMR) type or a Tunnel Magnetoresistiv.
(e; TMR) type magnetoresistive element, and stores information by utilizing the reversal of the magnetization direction in the magnetoresistive element.

A magnetoresistive element used in such an MRAM is, for example, a TMR type spin valve element configured as shown in FIGS. 10 (a) and 10 (b). That is, the free layer 71 and the fixed layer 72 made of a ferromagnetic material, the nonmagnetic layer 73 made of an insulator interposed therebetween, and the antiferromagnetic layer that directly or indirectly fixes the magnetization direction of the fixed layer 72. Layers 74 are sequentially laminated,
The resistance value of the tunnel current changes according to the magnetization direction in the free layer 71. Thereby, in the magnetoresistive effect element, it is possible to store information such as “1” when the magnetization is directed in one direction and “0” when the magnetization is directed in the other direction, according to the magnetization direction in the free layer 71. Become. Writing information to the magneto-resistance effect element is performed by applying a magnetic field having a value exceeding the magnetic field Hc necessary for reversing the magnetization direction of the free layer 71 from the outside and changing the magnetization direction of the free layer 71. Has become.

[0004]

By the way, in the magnetoresistive element, the free layer 7 when writing information is used.
It is desirable that the reversal operation of the magnetization direction of 1 be performed symmetrically with respect to the zero magnetic field. That is, the free layer 71
Regardless of the direction of magnetization, it is desirable that the operating point center at the time of the change be a zero magnetic field.

[0005] When the center of the operating point deviates from the zero magnetic field, due to the asymmetry, the operation for writing the information "1" to the magnetoresistive element and the operation for writing the information "0" to the magnetoresistive element. This is because there is a difference from the operation at the time. Such a difference causes an increase in a load on a circuit portion that generates an external magnetic field when writing information to the magnetoresistive element, and when a plurality of magnetoresistive elements are arranged close to each other in a matrix. In this case, it is not preferable because the operation margin of each magnetoresistive effect element is hindered.

However, in the magnetoresistive effect element, the effect of a magnetic field due to magnetostatic coupling between the free layer 71 and the fixed layer 72 (hereinafter referred to as a “static magnetic coupling magnetic field”)
The influence of a magnetic field (hereinafter, referred to as a “Neel coupling magnetic field”) generated due to unevenness at the interface is exerted. Such an effect on the free layer 71 causes a shift of the operation center point of the free layer 71 from the zero magnetic field, and therefore, should be suppressed as much as possible.

As shown in FIG. 11, the effect of the magnetostatic coupling magnetic field is caused by magnetic poles generated on the end face of the fixed layer 72 (see arrow A in the figure). Effect element size) and its magnetization amount. Therefore, if the element size is sufficiently large, the effect is reduced, and the above-mentioned problem of the shift of the operation center point can be solved. Also, even when the element dimensions are small,
For example, as disclosed in Japanese Patent Application Laid-Open No. 11-161919, if the net magnetization in the fixed layer 72 is made zero by using a laminated ferri-structure or the like, the effect of the magnetostatic coupling magnetic field on the free layer 71 is sufficiently reduced. It can be suppressed.

On the other hand, the effect of the Neel coupling magnetic field is
It occurs as follows. Each layer 71 including the free layer 71
Normally, layers 74 to 74 are formed by using a thin film technique. When microscopically viewing the interface between these layers 71 to 74, as shown in FIG. Are formed. Therefore, positive or negative magnetic poles such as + or-are formed in the vicinity of the uneven wall portions of the free layer 71 and the fixed layer 72. This means that the free layer 71 whose magnetization direction can be freely reversed is affected. That is, due to the influence, a Neel coupling magnetic field is generated in the free layer 71 such that the center of the operating point when the magnetization direction is reversed is shifted in a certain direction.
As a result, the center of the operating point deviates from the zero magnetic field.

Such a Neel coupling magnetic field is generated in each of the layers 71-71.
It is conceivable to avoid the occurrence by removing the irregularities at the interface 74. However, with the current thin film technology, it is impossible to completely remove irregularities, and it is practical to allow some irregularities in consideration of the production efficiency and the production cost of the magnetoresistive element.

Accordingly, the present invention provides a magnetoresistive element capable of adjusting the center of the operating point when the magnetization direction is reversed to zero magnetic field by eliminating the influence of the Neel coupling magnetic field even when it occurs. And a magnetic memory device using the magnetoresistive element.

[0011]

SUMMARY OF THE INVENTION The present invention is directed to a magnetoresistive element devised to achieve the above object, wherein at least a free layer made of a ferromagnetic material, a nonmagnetic layer made of a nonmagnetic material, and a ferromagnetic material. A fixed layer made of a body is laminated, and used in a magnetic memory device that performs information recording by using a change in the magnetization direction in the free layer, wherein the free layer is provided on the side where the fixed layer is not laminated. An antiferromagnetic layer made of an antiferromagnetic material is provided, and the free layer and the antiferromagnetic layer are joined via a second nonmagnetic layer made of a nonmagnetic material. .

The present invention also provides a magnetic memory device devised to achieve the above object, wherein at least a free layer made of a ferromagnetic material, a nonmagnetic layer made of a nonmagnetic material, and a fixed layer made of a ferromagnetic material Wherein the magneto-resistance effect element is formed by laminating, and the information is recorded by using the change in the magnetization direction in the free layer of the magneto-resistance effect element. An antiferromagnetic layer made of an antiferromagnetic material is provided on the side where the layers are not stacked, and the free layer and the antiferromagnetic layer are joined via a second nonmagnetic layer made of a nonmagnetic material. It is characterized by having been done.

According to the magnetoresistive element and the magnetic memory device having the above-described structures, the antiferromagnetic layer is joined to the free layer via the second nonmagnetic layer. The effect is due to the exchange bias at the interface. Moreover,
The magnitude of the effect varies depending on the thickness of the second nonmagnetic layer. Therefore, for example, even if a Neel coupling magnetic field is generated due to the state of the interface between the layers constituting the magnetoresistive element, the effect of the exchange bias by the antiferromagnetic layer acts in a direction opposite to the direction in which the Neel coupling magnetic field operates. Also, if the antiferromagnetic layer and the second nonmagnetic layer are formed so that the absolute amounts of influence of the free layer on both sides are substantially equal, the operating point center when the magnetization direction of the free layer changes is The deviation of the center of the operating point is corrected so as to match the zero magnetic field.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnetoresistive element and a magnetic memory device according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of a schematic configuration of a magnetoresistive element according to the present invention. As shown in the drawing, the magnetoresistive element 10 includes a free layer 11 made of a ferromagnetic material.
A non-magnetic layer 12 made of a non-magnetic material, a fixed layer 13 made of a ferromagnetic material, and an antiferromagnetic layer 14 for directly or indirectly fixing the magnetization direction of the fixed layer 13. In other words, the information recording is performed using the change in the magnetization direction in the free layer 11.

Further, on the side of the free layer 11 where the fixed layer 13 is not laminated, an antiferromagnetic layer made of an antiferromagnetic material (hereinafter referred to as a “second antiferromagnetic layer”) is provided separately from the antiferromagnetic layer 14. 15) are provided. And these free layers 11
The second antiferromagnetic layer 15 and the second antiferromagnetic layer 15 are joined to each other via a nonmagnetic layer 16 made of a nonmagnetic material (hereinafter, referred to as a “second nonmagnetic layer”). Note that the direction of anisotropy in the second antiferromagnetic layer 15 is substantially parallel to the magnetization direction in the fixed layer 13. Thereby, the magnetoresistance effect element 10
Is suitable for use in a magnetic memory device (MRAM) described later.

Next, a description will be given of a schematic configuration of a magnetic memory device constituted by using the magnetoresistive element 10 having the above-described structure, that is, the entire magnetic memory device according to the present invention. FIG. 2 is a schematic diagram illustrating a basic configuration example of a magnetic memory device called an MRAM.

As shown in FIG. 2A, in the MRAM,
A plurality of magnetoresistive elements 10 are arranged in a matrix. Furthermore, a word write line 20 and a bit write line 30 that intersect each other so as to correspond to each of the rows and columns where the magnetoresistive elements 10 are arranged.
Are provided so as to cross each group of the magnetoresistive elements 10 vertically and horizontally. Each of the magnetoresistive elements 10 is arranged so as to be sandwiched between the word write line 20 and the bit write line 30 from above and below, and to be located in an intersection region therebetween. One of the word write line 20 and the bit write line 30 is disposed substantially parallel to the easy axis direction of the free layer 11, and the other is disposed substantially parallel to the hard axis direction. For example, it is conceivable that the bit write line 30 is substantially parallel to the easy axis direction of the free layer 11.

In each of the magnetoresistive element portions, as shown in FIG. 2B, a gate region 42, a source region 43 and a drain region 44 are formed on a semiconductor substrate 41.
, A word write line 20, a magnetoresistive element 10, and a bit write line 30 are sequentially arranged above the field effect transistor 40. The free layer 11 in the magnetoresistive element 10
The information recorded in each magnetoresistive element 10 is read out by utilizing the fact that the current resistance value changes depending on the magnetization direction of the element.

On the other hand, information is written into each of the magneto-resistance effect elements 10 by using a combined current magnetic field generated by flowing a current through both the word write line 20 and the bit write line 30. Is performed by controlling the magnetization direction of the free layer 11 in the above. That is, the magnetic field for reversing the magnetization direction of the free layer 11 is
It is given by combining current magnetic fields flowing through the word write line 20 and the bit write line 30. As a result, the magnetization direction of only the selected magnetoresistive element 10 is inverted, and information is recorded. For the unselected magnetoresistive element 10, only the current magnetic field of one of the word write line 20 and the bit write line 30 is applied, so that the reversal magnetic field becomes insufficient and no information is written.

The combined current magnetic field required for this case is given by the asteroid curve ^{Hx (2/3) + Hy (2} /3) = Hk (2/3). Hk is the anisotropic magnetic field of the free layer 11. FIG. 3 is an asteroid diagram showing an example of a magnetic field response of the magnetoresistance effect element in the MRAM. The asteroid curve in the figure indicates the threshold value for reversing the magnetization direction of the magnetoresistive element 10. That is, when a combined current magnetic field corresponding to the outside of the asteroid curve is generated, the magnetization direction of the magnetoresistive element 10 is inverted. However, in the synthesized current magnetic field inside the asteroid, the magnetization direction of the magnetoresistance effect element 10 is not reversed from one of the current bistable states.

Incidentally, the magnetoresistive element 10 includes a free layer 11, a non-magnetic layer 12, a fixed layer 13, and an anti-ferromagnetic layer 1.
4 are stacked, so that each layer 1
There is a possibility that a Neel coupling magnetic field is generated due to the unevenness at the interface of Nos. 1 to 14, and the center of the operating point when the magnetization direction of the free layer 11 is reversed is shifted from the zero magnetic field. When such a shift of the center of the operating point from the zero magnetic field occurs, the center of the asteroid curve shifts in a certain direction from the origin on the Hx-Hy plane, and the operating margin in each magnetoresistive element 10 decreases, It is conceivable that the load on a pulse current generating circuit that applies a current to the word write line 20 or the like increases.

As described above, the free layer 11 is affected not only by the Neel coupling magnetic field but also by the magnetostatic coupling magnetic field. At this time, the effect of the magnetostatic coupling magnetic field depends on the size of the element and the like, and is applied to the free layer 11 in a direction opposite to the direction of the magnetization direction in the fixed layer 13. On the other hand, the effect of the Neel coupling magnetic field is applied to the free layer 11 in the same direction as the magnetization direction of the interface of the fixed layer 13 on the free layer 11 side without depending on the element size. Therefore, if the magnetoresistive effect element 10 is determined, the free layer 1 is set by setting the magnetization amount in the fixed layer 13 so that the effect of the magnetostatic coupling magnetic field and the effect of the Neel coupling magnetic field cancel each other.
It is also possible to adjust the operating point center at 1 to zero magnetic field.

However, in this case, when the element size changes, the amount of magnetization of the fixed layer 13 also needs to be changed correspondingly. Therefore, the versatility of the magnetoresistive effect element 10 and the flexibility in changing the design are improved. There is difficulty. In order to ensure versatility and flexibility, as described above, the dimensions are made sufficiently large, or the fixed layer 1 is formed using a laminated ferri-structure.
It is preferable to reduce the influence of the magnetostatic coupling magnetic field on the shift of the center of the operating point by setting the net magnetization of No. 3 to zero. However, for this purpose, it is necessary to correct the deviation of the operating point center due to the Neel coupling magnetic field separately from the influence of the magnetostatic coupling magnetic field.

Therefore, in each of the magnetoresistive elements 10, the exchange bias between the free layer 11 and the second antiferromagnetic layer 15 is used to determine the center of the operating point when the magnetization direction of the free layer 11 changes. The second antiferromagnetic layer 15 and the second nonmagnetic layer 16 are formed so as to have a zero magnetic field.

More specifically, as shown in FIG. 1, in each magnetoresistive element 10, the second antiferromagnetic layer 15 is provided. 1
5, the effect of the exchange bias at the interface between the layers, ie, a magnetic field in a certain direction acts (for example, NJ Gokenmeijer,
T. Ambrose and CLChein: J. Appl. Phys., 81, 4999 (19
97)). This is for substantially the same reason that the antiferromagnetic layer 14 directly or indirectly fixes the magnetization direction in the fixed layer 13.

Further, the second antiferromagnetic layer 15 is joined to the free layer 11 via the second nonmagnetic layer 16. Therefore, the magnitude of the influence of the exchange bias on the free layer 11 varies depending on the thickness of the second nonmagnetic layer 16. That is, as the second nonmagnetic layer 16 is thicker, the influence of the exchange bias on the free layer 11 by the second nonmagnetic layer 16 becomes smaller.

Therefore, in each magnetoresistive element 10, even if a Neel coupling magnetic field is generated, an exchange bias acts in a direction opposite to the direction in which the Neel coupling magnetic field acts, and the influence of the Neel coupling magnetic field and the exchange bias. By setting the amount of magnetization in the second antiferromagnetic layer 15 and the thickness of the second nonmagnetic layer 16 so that the absolute amounts of the two layers are substantially equal, the magnetization of the free layer 11 is independent of the element size. When the direction is changed, the center of the operating point matches the zero magnetic field, and the shift of the center of the operating point is corrected.

Here, the configuration of the magnetoresistive element 10 having the above features will be described in more detail with reference to specific examples. First, the magnetoresistive element 10 has a TMR
A spin valve element (hereinafter simply referred to as “TMR element”) will be described as an example.

FIG. 4 is a schematic view showing a specific example of the film configuration of the magnetoresistive element according to the present invention. As shown in the example,
The TMR element described here includes a 3 nm thick Ta film 21, a 2 nm thick Cu film 22, a 13 nm thick PtMn film 23, and a 1.5 nm thick CoFe film 24 a on a substrate 20.
And a 0.8 nm thick Ru film 24b and a 2 nm thick CoF
e film 24c, 1 nm thick Al-Ox film 25, 2 nm
Thick CoFe film 26 and a tnm thick Cu film 27 described later.
And a 13 nm thick PtMn film 28 and a 5 nm thick Ta film 29 are sequentially laminated. In addition, each film thickness is only an example, and is not limited to this.

Of these, the CoFe film 26 serves as the free layer 11, the Al-Ox film 25 serves as the nonmagnetic layer 12, and the PtM
The n films 23 function as the antiferromagnetic layers 14, respectively. Further, the laminated ferrimagnetic structure 24 in which the two CoFe films 24a and 24c are laminated via the Ru film 24b which is a nonmagnetic layer has a function as the fixed layer 13. Further, the PtMn film 28 serves as the second antiferromagnetic layer 15, and the Cu film 27 serves as the second nonmagnetic layer 16.
Each one works. The Ta film 2
Reference numerals 1 and 29 function as protective films, and the Cu film 22 functions as an insulating film.

In the TMR element having such a film structure, Cu
When the thickness t of the film 27 is changed, the magnitude of the influence of the exchange bias by the PtMn film 28 as the second antiferromagnetic layer 15 changes. Moreover, for example, when the element size of the TMR element is 10
If it is mm square, because of its very large element size,
The CoFe film 26 is hardly affected by the magnetostatic coupling magnetic field from the laminated ferri-structure portion 24 that is the fixed layer 13. Therefore, in this case, the shift amount of the operation center point in the CoFe film 26 serving as the free layer 11 is mainly determined by the influence of the Neel coupling magnetic field and the Pt that changes according to the thickness t of the Cu film 27.
It is determined by the exchange bias by the Mn film 28.

FIG. 5 is an explanatory diagram showing a specific example of the relationship between the thickness of the Cu film and the shift amount of the center of the operating point in the free layer. In the figure, the shift amount due to the influence of the Neel coupling magnetic field is positive. The shift amount of the operation center point in the CoFe film 26 is:
Since it is determined by the influence of the Neel coupling magnetic field and the exchange bias by the PtMn film 28, as shown in FIG.
It can be seen that by adjusting the thickness t of the Cu film 27, it is possible to realize a state where the shift amount of the operation center point becomes zero.

With the above-described film structure, in the TMR element, even if the influence of the Neel coupling magnetic field affects the CoFe film 26, the PtM that exerts an exchange bias on the CoFe film 26 is formed.
An n film 28 is provided, and Cu
By appropriately setting the thickness t of the film 27, the influence of the Neel coupling magnetic field can be eliminated, and the operating point center when the magnetization direction of the CoFe film 26 is reversed can be adjusted to zero magnetic field. Therefore, even when used in an MRAM, it is possible to avoid a decrease in the operation margin of each element, an increase in the load on the pulse current generation circuit, and the like. In addition, since the thickness does not depend on the element size, the thickness of each layer can be set for the element alone, and versatility of the TMR element and flexibility for design change can be secured.

The setting of the thickness t of the Cu film 27 may be performed based on a reference specified in advance, for example, a correspondence relationship as shown in FIG. However, it is assumed that the reference is empirically specified in advance, for example, from actual measurement results. Also, C
Since the exchange bias applied to the CoFe film 26 varies depending not only on the thickness t of the u film 27 but also on the magnetization amount in the PtMn film 28, it is needless to say that the magnetization amount needs to be taken into consideration.

In this case, CoFe is used as the magnetic material constituting the free layer 11 and the fixed layer 13.
Any of Co, Ni, Fe, an alloy containing at least one of these, or a stacked film thereof may be used. Further, PtMn is used as an antiferromagnetic material constituting the antiferromagnetic layer 14 and the second antiferromagnetic layer 15, but NiMn of an ordered alloy and Ir of an disordered alloy are also used.
Mn, RhMn, FeMn, oxide NiO, α-F
e2O3 may be used.

Further, here, a so-called bottom type TMR element in which the fixed layer 13 is laminated (below) the free layer 11 before the free layer 11 has been described as a specific example.
The present invention can be applied to a so-called top-type TMR element in which the free layer 11 is laminated (below) the fixed layer 13 as shown in FIG. In the illustrated example, the CoFe film 35 is used as the free layer 11 as Al.
The PtMn film 38 is formed by the Ox film 36 as the nonmagnetic layer 12, the laminated ferri-structure portion 37 in which the two CoFe films 37 a and 37 c are stacked via the Ru film 37 b as the fixed layer 13.
, The PtMn film 33 functions as the second antiferromagnetic layer 15, and the Cu film 34 functions as the second nonmagnetic layer 16.

Further, not only the TMR element but also a GMR type element in which the nonmagnetic layer 12 between the free layer 11 and the fixed layer 13 is made of Cu or the like as shown in FIG. It goes without saying that the same is true. In the illustrated example, the CoFe film 46 serves as the free layer 11 and the Cu film 45
Are two non-magnetic layers 12 through the Ru film 44b.
The laminated ferri-structure portion 44 in which the oFe films 44a and 44c are laminated is the fixed layer 13, the PtMn film 43 is the antiferromagnetic layer 14, the PtMn film 48 is the second antiferromagnetic layer 15, and the Cu film 47 is the second Each functions as the non-magnetic layer 16.

Next, another specific example in which the magnetoresistive element 10 is a TMR element will be described. FIG. 8 is a schematic view showing another specific example of the film configuration of the magnetoresistance effect element according to the present invention. As shown in the figure, the TMR described here
The element differs from the above-described specific example in that both the free layer 11 and the fixed layer 13 have a laminated ferri structure. That is, the laminated ferrimagnetic structure 56 in which the two CoFe films 56a and 56c are laminated via the Ru film 56b which is a non-magnetic layer functions as the free layer 11, and the two ferri-structures 56 via the Ru film 54b which is a non-magnetic layer. CoFe films 54a and 54c
Are laminated to function as the fixed layer 13. Further, as the second antiferromagnetic layer 15 corresponding to the laminated ferrimagnetic structure 56, IrMn
A film 58 is provided. The Al-Ox film 55 functions as the nonmagnetic layer 12, the PtMn film 53 functions as the antiferromagnetic layer 14, and the Cu film 57 functions as the second nonmagnetic layer 16, which is substantially the same as the specific example described above. It is.

In the TMR element having the above film configuration, since both the free layer 11 and the fixed layer 13 have a laminated ferrimagnetic structure, the PtMn as the second antiferromagnetic layer 15 is used.
It is necessary to reverse the direction of the magnetic field exerted by the exchange bias from the film 58 to the laminated ferri-structure portion 56, which is the free layer 11, in the above-described specific example. Therefore, the antiferromagnetic layer 14 and the second antiferromagnetic layer 15 are formed using different types of antiferromagnetic materials such as the PtMn film 53 and the IrMn film 58. The antiferromagnetic materials may be used in reverse.

The difference between these antiferromagnetic materials lies in the difference in their blocking temperatures. That is, if antiferromagnetic materials having different blocking temperatures are used for the antiferromagnetic layer 14 and the second antiferromagnetic layer 15, heat treatment in a magnetic field can be performed on both of them at a temperature at which one magnetization direction is not reversed.
Only the other magnetization direction can be fixed in the opposite direction. Therefore, even if both the free layer 11 and the fixed layer 13 have a laminated ferrimagnetic structure, the antiferromagnetic layer 14 and the second antiferromagnetic layer 15 can be oriented in opposite directions, thereby achieving the Neel coupling. Eliminating the effects of the magnetic field, Co
The operating point center when the magnetization direction of the Fe film 56a is reversed can be adjusted to zero magnetic field.

This means that the free layer 11 and the fixed layer 13
The same can be said not only when both have a laminated ferri structure, but also when both have a single-layer structure as shown in FIG. 9, for example. In the illustrated example, the CoFe film 66 serves as the free layer 11, the Cu film 65 serves as the nonmagnetic layer 12, the CoFe film 64 serves as the fixed layer 13, the PtMn film 63 serves as the antiferromagnetic layer 14, and the IrMn
The film 68 functions as the second antiferromagnetic layer 15, and the Cu film 67 functions as the second nonmagnetic layer 16.

That is, the antiferromagnetic layer 14 and the second nonmagnetic layer 1
6 is formed of the same antiferromagnetic material, if the fixed layer 13 has a laminated ferri structure as in the specific example described above, the operation center of the free layer 11 is controlled by the second nonmagnetic layer 16. It is possible to cancel the point shift. However, at this time, the laminated ferristructure is used for the fixed layer 13.
The present invention is not limited to this, and any one of the free layer 11 and the fixed layer 13 may be used. On the other hand, when both the free layer 11 and the fixed layer 13 have a laminated ferrimagnetic structure or a single-layer structure as in a specific example described later, the antiferromagnetic layer 14 and the second nonmagnetic layer 16 and 16 may be formed of different types of antiferromagnetic materials. Thereby, the antiferromagnetic layer 14
Since the magnetization directions of the free layer 11 and the second nonmagnetic layer 16 are opposite to each other, it is possible to cancel the shift of the operation center point in the free layer 11 in the second nonmagnetic layer 16.

[0044]

As described above, according to the magnetoresistive element and the magnetic memory device of the present invention, even when a Neel coupling magnetic field is generated, for example, the direction is opposite to the direction in which the Neel coupling magnetic field acts. Since the exchange bias by the antiferromagnetic layer acts in the direction, the reversal operation of the magnetization direction in the free layer is performed symmetrically with respect to the zero magnetic field in the positive and negative directions. As a result, the operation margin in each magnetoresistive element is secured. Is assured. In addition, by reducing the effect of the magnetostatic coupling magnetic field on the free layer, it is possible to realize a positive / negative symmetric inversion operation centered on the zero magnetic field without depending on the element size.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a schematic configuration of a magnetoresistive element according to the present invention.

2A and 2B are schematic diagrams illustrating a basic configuration example of a magnetic memory device called an MRAM, in which FIG. 2A is a diagram illustrating the overall schematic configuration, and FIG. 2B is a cross-sectional configuration of a single storage element portion. FIG.

FIG. 3 is an asteroid diagram showing an example of a magnetic field response of a magnetoresistive element in an MRAM.

FIG. 4 is a schematic view showing a specific example of a film configuration of a magnetoresistive element according to the present invention.

FIG. 5 is an explanatory diagram showing a specific example of a relationship between a thickness of a nonmagnetic layer between a free layer and an antiferromagnetic layer and a shift amount of an operating point center in the free layer.

FIG. 6 is a schematic diagram (part 1) illustrating a modification of the film configuration of the magnetoresistive element in FIG. 4;

FIG. 7 is a schematic view (part 2) illustrating a modification of the film configuration of the magnetoresistive element in FIG. 4;

FIG. 8 is a schematic diagram showing another specific example of the film configuration of the magnetoresistance effect element according to the present invention.

FIG. 9 is a schematic view showing a modification of the film configuration of the magnetoresistive element in FIG.

FIGS. 10A and 10B are schematic diagrams illustrating a configuration example of a general magnetoresistive element, and FIGS. 10A and 10B are diagrams illustrating an outline of an information storage state.

FIG. 11 is a schematic diagram showing an outline of a magnetostatic coupling magnetic field generated in a magnetoresistive element.

FIG. 12 is a schematic diagram showing an example of a state of an interface of each surface constituting the magnetoresistance effect element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Magnetoresistance effect element, 11 ... Free layer, 12 ... Nonmagnetic layer, 13 ... Fixed layer, 14 ... Antiferromagnetic layer, 15 ... Second antiferromagnetic layer, 16 ... Second nonmagnetic layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 43/08 G01R 33/06 R

Claims (7)

[Claims] At least a free layer made of a ferromagnetic material, a nonmagnetic layer made of a nonmagnetic material, and a fixed layer made of a ferromagnetic material are laminated, and information recording is performed by utilizing a change in a magnetization direction in the free layer. In the magnetoresistive effect element used in the magnetic memory device that performs the above, an antiferromagnetic layer made of an antiferromagnetic material is provided on a side of the free layer where the fixed layer is not stacked, and the free layer and the free layer A magnetoresistive element, wherein an antiferromagnetic layer is joined via a second nonmagnetic layer made of a nonmagnetic material. 2. The magnetoresistive element according to claim 1, wherein the magnetization direction of the fixed layer and the anisotropic direction of the antiferromagnetic layer are substantially parallel. 3. The semiconductor device according to claim 1, wherein one of the free layer and the pinned layer has a laminated ferrimagnetic structure in which two ferromagnetic materials are laminated via a nonmagnetic material. Magnetoresistive effect element. 4. When both the free layer and the fixed layer have a laminated ferri structure in which two ferromagnetic materials are stacked via a non-magnetic material or a single-layer structure made of one ferromagnetic material. The antiferromagnetic layer is formed of an antiferromagnetic material different in type from an antiferromagnetic layer provided for fixing the magnetization direction of the fixed layer on the side of the fixed layer where the free layer is not stacked. 2. The method according to claim 1, wherein
Or the magnetoresistive element according to 2. 5. The magnetoresistive element according to claim 1, wherein the magnetoresistive element is applied to a giant magnetoresistive element. 6. The magnetoresistive element according to claim 1, wherein the magnetoresistive element is applied to a tunnel magnetoresistive element. 7. A magneto-resistance effect element comprising at least a free layer made of a ferromagnetic material, a non-magnetic layer made of a non-magnetic material, and a fixed layer made of a ferro-magnetic material. In a magnetic memory device that performs information recording by using a change in magnetization direction in a layer, the magnetoresistive element includes an antiferromagnetic layer made of an antiferromagnetic material on a side of the free layer where the fixed layer is not stacked. And the free layer and the antiferromagnetic layer are joined via a second nonmagnetic layer made of a nonmagnetic material.