JP2021061388A - Magnetic memory element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic memory element capable of increasing a writing speed while suppressing power consumption. SOLUTION: A magnetic memory element 10 is provided with a recording layer 11 made of a magnetic material and a three-layer spin Hall effect layer (third) which is provided in contact with the recording layer 11 or via a predetermined intervening layer and is made of different materials. A write control unit 12 that is asymmetric in the thickness direction and has a plurality of sets of units 120 having one spin Hall effect layer 121, a second spin Hall effect layer 122, and a third spin Hall effect layer 133) arranged in the thickness direction. Has. Since the write control unit 12 is asymmetric in the thickness direction, the Rashba interaction becomes large, and when a current parallel to the spin Hall effect layer is passed through the write control unit 12, it collects on the recording layer 11 side in the laminate. It is possible to increase the number of electrons having a spin in one direction. Therefore, the torque for rotating the magnetization of the magnetic material of the recording layer 11 can be increased, and the writing speed can be increased while suppressing the power consumption. [Selection diagram] Fig. 1

Description

The present invention relates to a magnetic memory element that records information on a magnetic material.

In recent years, with the dramatic increase in the amount of information, a memory capable of recording information at a high density has been required. As such a memory, a flash memory is currently widely used. However, since the electrons pass through the oxide film in principle, the flash memory has a drawback that the number of writable times is limited due to the deterioration of the oxide film and the writing speed becomes slow while the information is repeatedly written. ..

A magnetic memory element has been proposed as a next-generation memory that overcomes such drawbacks. In a magnetic memory element, a magnetic material such as a ferromagnetic material or an antiferromagnetic material is generally used for a recording unit, and data is written by magnetizing the magnetic material in a specific direction. Since the magnetic memory element is less likely to be deteriorated than the flash memory due to such an operating principle, it can be written more times and the writing speed is less likely to decrease even if information is repeatedly written. Have.

Patent Document 1 uses a NiFe layer made of an alloy of Ni (nickel) and Fe (iron), which is a magnetic material, as a recording unit, and includes a Pt (platinum) layer, which is a substance having a spin Hall effect, in contact with the NiFe layer. Magnetic memory elements are described. Here, the spin Hall effect refers to an electron having an upward spin due to a Rashba interaction, which is one of spin-orbit interactions, when an electric current is passed through an object made of a substance having free electrons such as a metal or a semiconductor. A phenomenon in which electrons having a downward spin are separated in a direction perpendicular to the current. Hereinafter, the platinum layer is referred to as a write control unit. In this magnetic memory element, an electron having a specific unidirectional spin (either an upward spin or a downward spin) is passed through the write control unit by passing a current in one direction parallel to the interface with the recording unit. Gather near the interface. Due to the spin of the electrons, a torque is generated to rotate the magnetization of the magnetic material in the recording unit, and the magnetization is directed in a predetermined direction. Then, when a current in a direction different from the one direction is passed through the writing control unit, the direction of magnetization of the magnetic material in the recording unit changes. In this way, by setting the direction of the current flowing through the write control unit to either of the two directions, the magnetization of the magnetic material in the recording unit can be set to one of the two directions different from each other, and binary information can be sent to the recording unit. Can be written.

International release WO2008 / 123023

Masamitsu Hayashi and 3 others, "Quantitative characterization of the spin-orbit torque using harmonic Hall voltage measurements", Physical Review B, (USA), published by the American Physical Society, April 29, 2014, Vol. 89, 144425

Rashba interaction occurs when the spatial symmetry of the object through which the current flows is broken with respect to the direction perpendicular to the direction in which the current flows. In the magnetic memory element described in Patent Document 1, the spatial symmetry of the Pt layer, which is the write control unit, is broken only in the vicinity of the interfaces on both sides in the thickness direction, so that the Rashba interaction should be sufficiently increased. I can't. Therefore, it is not possible to sufficiently increase the number of electrons having a specific unidirectional spin that gather near the interface with the recording unit in the write control unit. As a result, the torque for rotating the magnetization of the magnetic material in the recording unit becomes small, and the time required for rotating the magnetization becomes long, so that the writing speed becomes slow. If the current flowing through the write control unit is increased, the torque for rotating the magnetization of the magnetic material can be increased to some extent, but the power consumption is increased.

An object to be solved by the present invention is to provide a magnetic memory element capable of increasing the writing speed while suppressing power consumption.

The first aspect of the magnetic memory element according to the present invention made to solve the above problems is
a) A recording layer with a magnetic material and
b) Asymmetrical in the thickness direction, in which a plurality of units having three spin Hall effect layers made of different substances, which are provided in contact with the recording layer or via a predetermined intervening layer, are arranged in the thickness direction. It is provided with a write control unit which is.

The spin Hall effect layer refers to a layer that exerts a spin Hall effect when an electric current is passed, that is, an effect that electrons having an upward spin and electrons having a downward spin are separated in a direction perpendicular to the current.

The unit has three spin Hall effect layers made of different materials. These three layers are the first spin Hall effect layer composed of the first substance (hereinafter, abbreviated as "A layer" depending on the necessity of simplification of display), and the second spin Hall effect composed of the second substance. Assuming that the layer (the same layer B) and the third spin Hall effect layer (the same layer C) are composed of the third substance, these three layers are "layer A, layer B, layer C" and "layer C" in the unit. "A layer, C layer, B layer", "B layer, A layer, C layer", "B layer, C layer, A layer", "C layer, A layer, B layer", "C layer, B layer," Multiple types of placement order can be taken, such as "A layer".

The plurality of sets of units of the write control unit have different arrangement orders for each layer (for example, units arranged in the order of "A layer, B layer, C layer" and "A layer, C layer, B". It may be (including units arranged in the order of "layers"). Further, the write control unit may have another spin Hall effect layer that does not belong to the unit as long as it has a plurality of such units. For example, a write control unit composed of "A layer, B layer, C layer, D layer, A layer, B layer, C layer" (D layer is a spin Hall effect layer composed of a fourth substance) is "A layer. It has two units consisting of ", B layer, C layer" and D layer that does not belong to the unit. In addition, the write control unit consisting of "A layer, B layer, C layer, A layer, B layer, A layer, B layer, C layer" is composed of two units consisting of "A layer, B layer, C layer". , Equipped with "A layer, B layer" that does not belong to the unit.

As a typical example of the write control unit, a unit in which layers A, B, and C are laminated in this order (in the same order) in each of a plurality of sets of units (hereinafter, referred to as "stacking order specifying unit") is used. be able to. In this case, the write control unit further comprises the plurality of sets of the stacking order specifying units (only) (specifically, "A layer, B layer, C layer, A layer, B layer, C layer, ... A". It has a structure of "layer, B layer, C layer").

"Asymmetric in the thickness direction" means that when the laminate is inverted in the thickness direction, it is not the same in the configuration in which the substance and the thickness are taken into consideration. For example, writing consisting of two sets of units in which A layer, B layer, and C layer are laminated in the thickness direction (in the order of "A layer, B layer, C layer, A layer, B layer, C layer"). If the control unit is inverted in the thickness direction, the arrangement order of each layer (in the order of "C layer, B layer, A layer, C layer, B layer, A layer") will be different from that before the inversion. Is asymmetrical. In addition, the A1 layer composed of substance A and the A2 layer, B layer, C layer and D layer having a thickness different from that of the A1 layer composed of substance A are referred to as "A1 layer, B layer, C layer, D layer, C layer, B layer". When the write control unit laminated in the order of "layer, A2 layer" is inverted in the thickness direction, the thickness of the uppermost layer and the lowermost layer will be different from those before the inversion, so that the writing control unit is asymmetrical in the thickness direction. Is.

In the magnetic memory element of the first aspect, since the write control unit is asymmetrical in the thickness direction, the spatial symmetry in the thickness direction is broken over the entire write control unit, and the Rashba interaction becomes large. As a result, it is possible to increase the number of electrons having a specific unidirectional spin that gathers on the recording layer side in the laminate when a current in a direction parallel to each spin Hall effect layer is passed through the laminate. Therefore, the torque for rotating the magnetization of the magnetic material of the recording layer can be increased without increasing the current flowing through the writing control unit, so that the writing speed can be increased while suppressing the power consumption.

The substance constituting each spin Hall effect layer is not particularly limited as long as it has a spin Hall effect. The substance may be a simple substance, an alloy or a compound.

The intervening layer refers to a layer that does not prevent the magnetization of the recording layer from being subjected to torque due to electron spins in a specific direction gathering on the recording layer side in the laminate (even if it is weakened to some extent).

The substance of at least one of the three spin Hall effect layers is a substance having a large spin Hall effect, such as Hf (hafnium), Ta (tantalum), W (tungsten), Re (rhenium), and Os (osnium). ), Ir (iridium), Pt (platinum), Au (gold).

In order to increase the Rashba interaction, it is desirable that the thickness of at least one of the three spin Hall effect layers is small, for example, 0.1 to 2 nm (1 to 20 Å).

The second aspect of the magnetic memory element according to the present invention is
a) A recording layer with a magnetic material and
b) A laminated body in which three or more spin Hall effect layers made of substances different from each other are asymmetrically laminated in the thickness direction, which are provided in contact with the recording layer or via a predetermined intervening layer. It is provided with a write control unit which is.

In the magnetic memory element of the second aspect, the write control unit is a laminated body in which three or more spin Hall effect layers made of different substances are asymmetrically laminated in the thickness direction between adjacent layers. Spatial symmetry in the thickness direction is broken throughout the laminate, increasing the Rashba interaction. As a result, it is possible to increase the number of electrons having a specific unidirectional spin that gathers on the recording layer side in the laminate when a current in a direction parallel to each spin Hall effect layer is passed through the laminate. Therefore, the torque for rotating the magnetization of the magnetic material of the recording layer can be increased without increasing the current flowing through the writing control unit, so that the writing speed can be increased while suppressing the power consumption.

In the second aspect as well, as in the first aspect, the substance constituting each spin Hall effect layer is not particularly limited as long as it has a spin Hall effect. The substance may be a simple substance, an alloy or a compound. Further, the laminate in the second aspect has a spin Hall effect layer made of the same substance as long as it has three or more spin Hall effect layers made of different substances between adjacent layers. You may. Further, the intervening layer in the second aspect gives torque due to electron spins in a specific direction gathering on the recording layer side in the laminated body to the magnetization of the recording layer (even if it weakens to some extent), as in the first aspect. A layer that does not prevent things from happening.

In the second aspect, the substance of at least one of the three or more spin Hall effect layers is a substance having a large spin Hall effect, such as Hf, Ta, W, Re, Os, Ir, Pt, and Au. It is desirable to be one of them.

In the second aspect, it is desirable that at least one of the three or more spin Hall effect layers has a small thickness, for example, 0.1 to 2 nm (1 to 20 Å).

According to the magnetic memory element according to the present invention, the writing speed can be increased while suppressing the power consumption.

A vertical sectional view (a) and a bottom view (b) showing an embodiment of the magnetic memory element according to the present invention. It is a vertical cross-sectional view which shows the operation of the magnetic memory element of this embodiment, (a) "0" writing, (b) "1" writing, (c) "0" reading, and (d) " The figure which shows the reading of "1". The graph which shows the result of having measured the Hall angle ζ in the case of a plurality of cases where the thickness of the 3rd spin Hall effect layer (W layer) is different in the write control part in the magnetic memory element of this embodiment. Another graph showing the result of measuring the Hall angle ζ in the case where the thickness of the first spin Hall effect layer (Pt layer) is different in the write control unit of the magnetic memory element of the present embodiment. Another graph showing the result of measuring the hole angle ζ in the case where the number of stacking order specifying units is different in the write control unit of the magnetic memory element of the present embodiment. The vertical sectional view which shows the modification of the magnetic memory element of this embodiment. The vertical sectional view which shows the other modification of the magnetic memory element of this embodiment. The vertical sectional view which shows the other modification of the magnetic memory element of this embodiment.

An embodiment of the magnetic memory element according to the present invention will be described with reference to FIGS. 1 to 8.

(1) Configuration of Magnetic Memory Element of the Present Embodiment The configuration of the magnetic memory element 10 of the present embodiment will be described. The magnetic memory element 10 satisfies both the constituent requirements of the magnetic memory element of the first aspect and the constituent requirements of the magnetic memory element of the second aspect. The magnetic memory element 10 has a recording layer 11 and a write control unit 12.

The recording layer 11 is a layered member having a magnetic material. As the material of the recording layer 11, a ferromagnet composed of Fe, Ni, an alloy thereof, or the like can be used. Instead of the ferromagnetic material, a magnetic material such as an antiferromagnetic material, a ferrimagnetic material, or a weak ferromagnetic material may be used. In the present embodiment, as described later, a magnetic material having conductivity is used to measure the direction of magnetization of the recording layer 11, but depending on the method of measuring the direction of magnetization, a magnetic material having no conductivity is used. May be good.

The write control unit 12 is parallel to the layered recording layer 11 and is laminated in the order of the first spin Hall effect layer 121, the second spin Hall effect layer 122, and the third spin Hall effect layer 123 (in order from the recording layer 11). It is a laminated body in which a plurality of sets (for example, 10 sets) are repeatedly laminated with one set of the stacking order specifying unit 120). The first spin Hall effect layer 121, the second spin Hall effect layer 122, and the third spin Hall effect layer 123 have a spin Hall effect and are made of different substances. In the present embodiment, Pt is used for the first spin Hall effect layer 121, Co is used for the second spin Hall effect layer 122, and W is used for the third spin Hall effect layer 123. Hereinafter, the individual spin Hall effect layers (first spin Hall effect layer 121, second spin Hall effect layer 122, and third spin Hall effect layer 123) are collectively referred to as "spin Hall effect layer 12X".

When the laminated body of the write control unit 12 is inverted in the thickness direction, the stacking order of each spin Hall effect layer 12X is the first spin Hall effect layer 121, the second spin Hall effect layer 122, and the third spin Hall effect layer 123. Since the order changes in the order of the third spin Hall effect layer 123, the second spin Hall effect layer 122, and the first spin Hall effect layer 121, it is asymmetric in the thickness direction. Therefore, in this laminated body, the spatial symmetry is broken in the thickness direction.

In the present embodiment, each spin Hall effect layer 120 is set to 0.1 to 2 nm (1 to 20 Å) so that the thickness per layer is 10 atoms or less in order to increase the Rashba interaction. In the present embodiment, as described above, the thickness of each spin Hall effect layer 120 is the same because the laminated body of the write control unit 12 can be made asymmetric in the thickness direction due to the difference in the substance of each spin Hall effect layer 120. May be. Further, the thickness may be different for each spin Hall effect layer 120.

An information writing unit 13 is connected to the writing control unit 12. The information writing unit 13 passes a current in one direction parallel to each spin Hall effect layer 120 (a direction perpendicular to the paper surface in FIG. 1 (a); a lateral direction in (b)), and sets the direction of the current. It has a mechanism for reversing. In FIG. 1, the current from the front to the back (from the top to the bottom of (b)) in (a) is "+ I", and the current from the back to the front (from the bottom to the top in (b)) in FIG. 1 (a) is. It is written as "-I".

An information reading unit 14 is connected to the recording layer 11. The information reading unit 14 reads out the information recorded in the recording layer 11 as described later by measuring the electrical resistance in the direction parallel to the current flowing through the writing control unit 12 by the information writing unit 13.

(2) Operation of Magnetic Memory Element 10 of the Present Embodiment The operation of the magnetic memory element 10 of the present embodiment will be described with reference to the vertical cross-sectional view of FIG. In the example shown in FIG. 2, the magnetic memory element 10 is oriented to the right when the magnetization M of the magnetic material of the recording layer 11 is directed to the left in FIG. 2 (see FIGS. 2 (a) and 2 (c)). (See (b) and (d)), different binary values are recorded. Here, the case where the magnetization M is directed to the left in FIG. 2 is defined as “0”, and the case where the magnetization M is directed to the right is defined as “1”.

(2-1) Writing "0" (Fig. 2 (a))
When writing "0" to the recording layer 11, the information writing unit 13 causes the writing control unit 12 to pass a current "-I" from the back to the front of FIG. As a result, in the write control unit 12, due to the spin Hall effect, electrons having spin S pointing to the left in FIG. 2 are unevenly distributed near the interface on the recording layer 11 side, and electrons having spin S'in the opposite direction are unevenly distributed near the interface. It is unevenly distributed near the interface on the opposite side of the recording layer 11. Then, the magnetization M of the magnetic material of the recording layer 11 receives torque from the spins S of electrons unevenly distributed near the interface on the recording layer 11 side of the writing control unit 12, and faces the left direction in FIG. In this way, the information indicating "0" is written to the recording layer 11.

(2-2) Writing "1" (Fig. 2 (b))
When writing "1" to the recording layer 11, the information writing unit 13 causes the writing control unit 12 to pass a current "+ I" from the front to the back of FIG. As a result, in the write control unit 12, due to the spin Hall effect, the electrons having the spin S pointing to the right in FIG. 2 are unevenly distributed near the interface on the recording layer 11 side, and the electrons having the spin S'in the opposite direction are unevenly distributed near the interface. It is unevenly distributed near the interface on the opposite side of the recording layer 11. Then, the magnetization M of the magnetic material of the recording layer 11 receives torque from the spins S of electrons unevenly distributed near the interface on the recording layer 11 side of the writing control unit 12, and faces the right direction in FIG. In this way, the information indicating "1" is written in the recording layer 11.

(2-3) Reading information (Fig. 2 (c), (d))
When reading the information recorded on the recording layer 11, the information reading unit 14 measures the electrical resistance of the recording layer 11 in the left-right direction of FIG. Electrical resistance, the left-right direction to the current in FIG. 2 (this current is referred to as "resistance measurement current") while flowing I _r by measuring the voltage across the recording layer 11 with a voltmeter, dividing the voltage value by the current value Can be obtained by When information recorded on the recording layer 11 is "0", whereas the magnetization M of the recording layer 11 is a resistance measurement current I _r in the opposite direction (FIG. 2 (c)), recorded in the recording layer 11 it is when it has information of "1" which is a magnetization M resistance measurement current I _r in the same direction as the recording layer 11 (Figure 2 (d)). Therefore, when information is the time of "0" and "1", different in size of the electronic undergoes scattering of the electron resistance measurement from the spin current I _r in the recording layer 11 to form a magnetization M, the information read The electrical resistance measured by unit 14 is also different. Due to this difference in electrical resistance, it is possible to read whether the information recorded on the recording layer 11 is "0" or "1".

(3) Experiment for confirming the characteristics of the write control unit in the magnetic memory element of the present embodiment In order to confirm the characteristics of the write control unit 12, the current and spin current (charge) in the laminate constituting the write control unit 12 are described below. The spin Hall angle ζ, which is a parameter indicating the conversion efficiency of the spin flow that moves independently of the above, was measured by the method described in Non-Patent Document 1.

The number of stacking order specifying units 120 is 12, the thickness of the first spin Hall effect layer (Pt layer) 121 is 1.0 nm, and the thickness of the second spin Hall effect layer (Co layer) 122 is 0.6 nm. FIG. 3 shows the results of obtaining the values of the spin Hall angle ζ for each of a plurality of samples in which the thickness of the third spin Hall effect layer (W layer) 123 differs within the range of 0.2 to 1.0 nm. Further, the thickness of the second spin Hall effect layer (Co layer) 122 is 0.6 nm, the thickness of the third spin Hall effect layer (W layer) 123 is 0.6 nm, and the thickness of the first spin Hall effect layer (Pt layer) is 0.6 nm. ) The results of obtaining the values of the spin Hall angle ζ for each of a plurality of samples having a thickness of 121 different in the range of 1.0 to 4.0 nm are shown in FIG. The sample having a W layer thickness of 0.6 nm in FIG. 3 and the sample having a Pt layer thickness of 1.0 nm in FIG. 4 are the same sample. These FIGS. 3 and 4 show two data described as "FL" and "DL", respectively. "FL" is an abbreviation of "Field Like", and indicates a case where a torque in a direction parallel to a magnetic field that precesses a spin by the obtained spin current is applied to the spin. "DL" is an abbreviation of "Damping Like", and the magnetic field that precesses the spin by the obtained spin current and the torque in the direction perpendicular to the spin (the direction of the magnetic field and the outer product of the spin) are applied to the spin. Indicates the case where it is done.

The thickness of the first spin Hall effect layer (Pt layer) 121 is 1.0 nm, the thickness of the second spin Hall effect layer (Co layer) 122 is 0.6 nm, and the thickness of the third spin Hall effect layer (W layer) 123. FIG. 5 shows the results of obtaining the values of the spin Hall angle ζ for each of a plurality of samples in which the value is 0.6 nm and the number of stacking order specifying units 120 is different within the range of 6 to 15. The sample in which the number of stacking order specifying units 120 is 12 is from the same wafer as the sample in which the thickness of the W layer 123 in FIG. 3 is 0.6 nm (the sample in which the thickness of the Pt layer is 1.0 nm in FIG. 4). This is another sample prepared. The spin Hall angle increases as the number of stacking order specifying units 120 increases, except when the number of stacking order specifying units 120 is 15. It is considered that the decrease in the spin Hall angle when the number of stacking order specifying units 120 is 15, is due to the accuracy of sample preparation.

In a single spin Hall effect layer, which is a write control unit in a conventional magnetic memory element, the value of the spin Hall angle ζ is usually 0.1 and a maximum of 0.3 in the case of tungsten, which is known as a substance having a large spin Hall effect. Degree. On the other hand, in the present embodiment, the number of stacking order specifying units 120 is 12, the thickness of the first spin Hall effect layer (Pt layer) 121 is 1.0 nm, and the second and third spin Hall effect layers (Co layer, W). When the thickness of layers 122 and 123 is 0.6 nm, the maximum spin Hall angle ζ is 0.4 (in the case of DL) and 0.6 (in the case of FL), which are high values not found in a single spin Hall effect layer. Obtained. The value of the spin Hall angle ζ of 0.6 is that the write control unit in the magnetic memory element of the present embodiment can obtain a spin current 5 to 10 times larger than that of the conventional write control unit composed of a single spin Hall effect layer. Means. Therefore, according to the magnetic memory element 10 of the present embodiment, the torque for rotating the magnetization of the magnetic material of the recording layer 11 can be increased without increasing the current flowing through the write control unit 12, so that the power consumption is increased. The writing speed can be increased while suppressing the pressure.

In the write control unit 12 of the present embodiment, a single spin Hall effect layer made of tungsten depends on the number of stacking order specifying units 120 and the thickness of the first to third pinhole effect layers 121 to 123. Some have a spin Hall angle ζ similar to that of the write control unit using the above (referred to as “tungsten single write control unit”). For example, the number of stacking order specifying units 120 is 6, the thickness of the first spin Hall effect layer (Pt layer) 121 is 1.0 nm, and the thickness of the second and third spin Hall effect layers (Co layer, W layer) 122 and 123. When the value is 0.6 nm, the spin Hall angle ζ is about 0.1 (both DL and FL). Even in such a case, as described below, the write control unit in the present embodiment has a feature that the electric resistance can be made smaller than that of the tungsten single write control unit. That is, in order for the tungsten single write control unit to have an electrical resistivity of 100 to 300 μΩ · cm and a spin Hall angle ζ of 0.1 to 0.3, it is about one layer of the spin Hall effect layer in the present embodiment. Must be the thickness of. On the other hand, the write control unit 12 in the present embodiment can obtain an electrical resistivity of 80 to 100 μΩ · cm, which is lower than that of the tungsten single write control unit. Further, the write control unit 12 has a plurality of spin Hall effect layers laminated on top of each other, and is thicker than the tungsten single write control unit. Therefore, the electric resistance of the write control unit 12 in the present embodiment can be made lower than the electric resistance of the tungsten single write control unit.

The present invention is not limited to the above embodiment, and various modifications are possible.

In the above embodiment, Pt, Co, and W are used as substances that are the materials of each of the three types of spin Hall effect layers, but the substances are not limited to these substances, and any substance having a spin Hall effect can be used. it can. Further, the material of each spin Hall effect layer may be composed of a single element, or may be an alloy or a compound. The material of each spin Hall effect layer is preferably one of Hf, Ta, W, Re, Os, Ir, Pt, Au) in that the spin Hall effect is large. On the other hand, even if a material other than these materials (for example, Co in the above embodiment) is used, a sufficient spin Hall effect can be obtained by appropriately combining spin Hall effect layers made of different materials (substances). The material may be determined in consideration of cost and the like.

The stacking order of the first spin Hall effect layer 121, the second spin Hall effect layer 122, and the third spin Hall effect layer 123 is not limited to the above example, and can be arbitrarily changed. Further, in the second aspect, these three types of layers may be randomly laminated.

The magnetic memory element 10A of the modified example shown in FIG. 6 has a plurality of types of units 120A and 120B in which the stacking order of the first spin Hall effect layer 121, the second spin Hall effect layer 122, and the third spin Hall effect layer 123 is different. The writing control unit 12A in which 120C ... Is arranged in the thickness direction is provided. In the unit 120A, the first spin Hall effect layer 121, the second spin Hall effect layer 122, and the third spin Hall effect layer 123 are laminated in order from the recording layer 11. In the unit 120B, each spin Hall effect layer is laminated in the order of the second spin Hall effect layer 122, the first spin Hall effect layer 121, and the third spin Hall effect layer 123 from the upper side. In the unit 120C, each spin Hall effect layer is laminated in the order of the first spin Hall effect layer 121, the third spin Hall effect layer 123, and the second spin Hall effect layer 122 from the upper side. The entire write control unit 12A is asymmetrical in the thickness direction. Although three types of units 120A, 120B, and 120C are shown in FIG. 6, the writing control unit may include units having a stacking order of spin Hall effect layers other than these.

The magnetic memory element 10B of the modified example shown in FIG. 7 is composed of a first spin Hall effect layer 121, a second spin Hall effect layer 122, a third spin Hall effect layer 123, and a fourth material different from these three layers. A write control unit 12B having a structure in which the spin Hall effect layer 124 is repeatedly laminated in this order is provided. This configuration corresponds to the stacking order specifying unit 120 in the magnetic memory element 10 with the fourth spin Hall effect layer 124 added. The entire write control unit 12B is asymmetric in the thickness direction.

The magnetic memory element 10C of the modified example shown in FIG. 8 has a configuration in which one of the plurality of third spin Hall effect layers 123 is omitted from the magnetic memory element 10 described above. The write control unit 12C in the magnetic memory element 10C has the first spin Hall effect layer 121A of the first layer and the second spin Hall effect layer 122A of the first layer remaining due to the omission of the third spin Hall effect layer 123 of the first layer. At the same time, it has a plurality of sets of stacking order specifying units 120. The entire write control unit 12C is asymmetrical in the thickness direction.

In the present embodiment, the write control unit 12 is provided so as to be in contact with the recording layer 11, but is gathered between the recording layer 11 and the write control unit 12 on the recording layer 11 side in the laminated body, for example, a conductive member or the like. An intervening layer may be provided that does not prevent the torque due to the electron spin in a specific direction from being applied to the magnetization of the recording layer 11 (even if it is weakened to some extent).

In the above embodiment, as a configuration for writing information to the recording layer 11, a device having a mechanism for passing a current in one direction parallel to each spin Hall effect layer 120 and reversing the direction of the current is used. Instead, a current may be used in one direction parallel to each spin Hall effect layer 120 and in a direction parallel to the spin Hall effect layer 120 and perpendicular to the one direction. In this case, binary information can be recorded by directing the magnetization of the recording layer 11 to any of the directions 90 ° different from each other due to the difference in the direction of the current, and the write control unit 12 can record the difference in the direction of the magnetization. Information can be read out by the difference in electrical resistance that occurs. Such a configuration in which the magnetization of the recording layer 11 is directed to any of the directions 90 ° different from each other can be preferably used particularly when the recording layer 11 has an antiferromagnetic material.

10 ... Magnetic memory element 11 ... Recording layer 12 ... Write control unit 120 ... Stacking order specifying units 120A, 120B, 120C ... Units 12X ... Spin Hall effect layers 121, 121A ... First Spin Hall effect layers 122, 122A ... 2nd spin Hall effect layer 123 ... 3rd spin Hall effect layer 124 ... 4th spin Hall effect layer 13 ... Information writing unit 14 ... Information reading unit

Claims (8)

a) A recording layer with a magnetic material and
b) Asymmetric in the thickness direction, in which a plurality of units having three spin Hall effect layers made of different substances, which are provided in contact with the recording layer or via a predetermined intervening layer, are arranged in the thickness direction. A magnetic memory element including a write control unit. Each of the units is a stacking order specifying unit in which the first spin Hall effect layer, the second spin Hall effect layer, and the third spin Hall effect layer made of different substances are laminated in this order. The magnetic memory element according to claim 1. The magnetic memory element according to claim 2, wherein the write control unit includes the plurality of sets of the stacking order specifying units. Any one of claims 1 to 3, wherein the substance of at least one of the three spin Hall effect layers is any of Hf, Ta, W, Re, Os, Ir, Pt, and Au. The magnetic memory element described in 1. The magnetic memory element according to any one of claims 1 to 4, wherein at least one of the three spin Hall effect layers has a thickness of 0.1 to 2 nm. a) A recording layer with a magnetic material and
b) A laminated body in which three or more spin Hall effect layers made of substances different from each other are asymmetrically laminated in the thickness direction, which are provided in contact with the recording layer or via a predetermined intervening layer. A magnetic memory element including a write control unit. The magnetic memory device according to claim 6, wherein the substance of at least one of the three or more spin Hall effect layers is any one of Hf, Ta, W, Re, Os, Ir, Pt, and Au. .. The magnetic memory element according to claim 6 or 7, wherein at least one of the three or more spin Hall effect layers has a thickness of 0.1 to 2 nm.

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