阅读说明：本技术 多功能磁性随机存储单元、存储器及设备 (Multifunctional magnetic random access memory cell, memory and device ) 是由 王旻 王昭昊 王朝 赵巍胜 于 2020-12-31 设计创作，主要内容包括：本发明提供了一种多功能磁性随机存储单元、存储器及设备,多功能磁性随机存储单元包括自旋轨道耦合层、设于所述自旋轨道耦合层上的至少一个磁隧道结以及外加磁场,其中,所述至少一个磁隧道结的自由层受到DMI效应作用；当向所述自旋轨道耦合层输入第一自旋轨道矩电流时,所述磁隧道结的阻态与自旋轨道矩电流的方向对应；当向所述自旋轨道耦合层输入第二自旋轨道矩电流时,所述磁隧道结的阻态发生改变,本发明可使磁隧道结可以在不同自旋轨道矩电流输入条件下分别实现单极性翻转和双极性翻转。(The invention provides a multifunctional magnetic random storage unit, a memory and equipment, wherein the multifunctional magnetic random storage unit comprises a spin orbit coupling layer, at least one magnetic tunnel junction arranged on the spin orbit coupling layer and an external magnetic field, wherein the free layer of the at least one magnetic tunnel junction is subjected to the action of DMI effect; when a first spin orbit torque current is input to the spin orbit coupling layer, the resistance state of the magnetic tunnel junction corresponds to the direction of the spin orbit torque current; when the second spin orbit torque current is input to the spin orbit coupling layer, the resistance state of the magnetic tunnel junction is changed, and the invention can enable the magnetic tunnel junction to respectively realize unipolar turning and bipolar turning under different spin orbit torque current input conditions.)

1. A multifunctional magnetic random access memory unit is characterized by comprising a spin orbit coupling layer, at least one magnetic tunnel junction arranged on the spin orbit coupling layer and an external magnetic field, wherein the free layer of the at least one magnetic tunnel junction is subjected to the action of DMI effect;

when a first spin orbit torque current is input to the spin orbit coupling layer, the resistance state of the magnetic tunnel junction corresponds to the direction of the spin orbit torque current; when a second spin orbit torque current is input to the spin orbit coupling layer, the resistance state of the magnetic tunnel junction is changed.

2. The multi-functional magnetic random memory unit of claim 1, wherein the first spin orbit torque current is less than a first critical current, the second spin orbit torque current is greater than a first critical current and less than a second critical current, the first and second critical currents determined from the strength of the applied magnetic field and the strength of the DMI effect; alternatively, the first and second electrodes may be,

the first spin orbit torque current is larger than a second critical current, the second spin orbit torque current is larger than a first critical current and smaller than a second critical current, and the first critical current and the second critical current are determined according to the intensity of the externally-applied magnetic field and the intensity of the DMI effect; alternatively, the first and second electrodes may be,

the first spin orbit torque current is smaller than a first critical current or larger than a second critical current, the second spin orbit torque current is larger than the first critical current and smaller than the second critical current, and the first critical current and the second critical current are determined according to the intensity of the externally-applied magnetic field and the intensity of the DMI effect.

3. The multi-functional magnetic random access memory cell of claim 1 wherein the resistance state of the magnetic tunnel junction is a first resistance state when the spin-orbit coupling layer inputs a first spin-orbit torque current in a forward direction and a second resistance state when the spin-orbit coupling layer inputs a first spin-orbit torque current in a reverse direction.

4. The multi-functional magnetic random access memory cell of claim 1, wherein the magnetic tunnel junction is elliptical, and the first spin-orbit torque current comprises a first current input along a length or width direction of a spin-orbit coupling layer;

the second spin orbit torque current includes a second current input along the major or minor axis of the ellipse.

5. The multi-functional magnetic random access memory cell of claim 4 wherein the spin-orbit coupling layer length direction comprises a first direction and a second direction that face each other, and the width direction comprises a third direction and a fourth direction that face each other;

the second current is obtained by compounding the sub-current input along the first direction or the second direction and the sub-current input along the third direction or the fourth direction.

6. The multi-functional magnetic random access memory cell of claim 1,

the storage unit comprises a magnetic field generating device for providing the external magnetic field or equivalently providing the external magnetic field; alternatively, the first and second electrodes may be,

the magnetic tunnel junction comprises a fixed layer, a barrier layer and a free layer which are sequentially arranged from top to bottom, wherein the section of at least one of the fixed layer, the barrier layer and the free layer is trapezoidal and is used for providing the external magnetic field; alternatively, the first and second electrodes may be,

the spin orbit coupling layer is made of an antiferromagnetic material, and forms an exchange bias field with the free layer and is used for providing the external magnetic field; alternatively, the first and second electrodes may be,

the magnetic tunnel junction comprises a magnetic material layer for providing the externally applied magnetic field; alternatively, the first and second electrodes may be,

the magnetic tunnel junction has a shape capable of forming a shape anisotropy field for providing an equivalent magnetic field of the externally applied magnetic field; alternatively, the first and second electrodes may be,

the free layer has a perpendicular anisotropy of gradient for providing an equivalent magnetic field to the externally applied magnetic field.

7. The multifunctional magnetic random access memory cell of claim 1 wherein the DMI effect has a strength of 0.1-3mJ/m²。

8. The multi-functional magnetic random access memory cell of claim 1, further comprising a control circuit;

the control circuit is used for reading the resistance state of the magnetic tunnel junction, determining whether the resistance state of the magnetic tunnel junction needs to be changed or not according to the resistance state of the magnetic tunnel junction and the data to be written, and if yes, inputting a second current to the spin orbit coupling layer to change the resistance state of the magnetic tunnel junction so as to write the data to be written.

9. A multifunctional magnetic random access memory comprising a plurality of multifunctional magnetic random access memory cells of any of claims 1-8 arranged in an array.

10. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor,

the processor and/or the memory comprise a multifunctional magnetic random access memory unit according to any of claims 1-8.

Technical Field

The present invention relates to the field of semiconductor device technology, and more particularly, to a multifunctional magnetic random access memory cell, a memory and a device.

Background

With the continuous reduction of the semiconductor process size, moore's law is slowed down, and the increase of leakage current and interconnection delay become the bottleneck of the conventional CMOS memory. Magnetic Random Access Memory (MRAM) has the advantages of unlimited erasing and writing times, nonvolatility, high reading and writing speed, irradiation resistance and the like, is expected to become a universal memory, and is an ideal device for constructing a next-generation nonvolatile main memory and cache. The magnetic tunnel junction is a basic memory cell of the magnetic random access memory. The Spin-torque transfer magnetic random access memory (STT-MRAM) has the disadvantages of long incubation time, read-write interference and the like, and limits the further development of the STT-MRAM. Spin-orbit torque magnetic random access memory (Spin-orbit torque MRAM, SOT-MRAM) receives wide attention from the industry and academia due to its advantages of fast writing speed, separate read and write paths and low power consumption.

The current SOT-MRAM data writing based on spin orbit torque can be divided into two modes according to the path dependence, one mode is unipolar inversion, and the other mode is bipolar inversion. The unipolar switching means that the resistance state of the magnetic tunnel junction changes only by the spin orbit torque current, for example, the high resistance state changes to the low resistance state, and the low resistance state changes to the high resistance state. In the manner of unipolar inversion, in the conventional data writing, a corresponding pre-reading circuit needs to be designed, so that the complexity of each data writing operation is relatively high, but an efficient inversion operation can be realized in logic application. The final resistance state of the magnetic tunnel junction during bipolar switching is related to the current direction, so that the complexity of writing operation is relatively low. The common spin orbit torque data writing method using external magnetic field inversion is typical bipolar inversion, and the final resistance state of a magnetic tunnel junction is controlled by controlling the direction of current in the data writing process, so that the data writing is realized. The current spin orbit torque magnetic random memory can only realize one data writing mode of unipolar inversion or bipolar inversion, and the wide application of the magnetic random memory is limited.

Disclosure of Invention

The invention aims to provide a multifunctional magnetic random access memory unit, which can respectively realize unipolar switching and bipolar switching of a magnetic tunnel junction under different spin orbit torque current input conditions by combining an external magnetic field and a DMI effect. It is another object of the present invention to provide a multifunctional magnetic random access memory. It is a further object of the present invention to provide a computer apparatus.

In order to achieve the above object, the present invention discloses a multifunctional magnetic random access memory cell, including a spin-orbit coupling layer, at least one magnetic tunnel junction disposed on the spin-orbit coupling layer, and an external magnetic field, wherein a free layer of the at least one magnetic tunnel junction is subject to a DMI effect;

when a first spin orbit torque current is input to the spin orbit coupling layer, the resistance state of the magnetic tunnel junction corresponds to the direction of the spin orbit torque current; when a second spin orbit torque current is input to the spin orbit coupling layer, the resistance state of the magnetic tunnel junction is changed.

Preferably, the first spin orbit torque current is smaller than a first critical current, the second spin orbit torque current is larger than the first critical current and smaller than a second critical current, and the first critical current and the second critical current are determined according to the intensity of the externally-applied magnetic field and the intensity of the DMI effect; alternatively, the first and second electrodes may be,

the first spin orbit torque current is larger than a second critical current, the second spin orbit torque current is larger than a first critical current and smaller than a second critical current, and the first critical current and the second critical current are determined according to the intensity of the externally-applied magnetic field and the intensity of the DMI effect; alternatively, the first and second electrodes may be,

the first spin orbit torque current is smaller than a first critical current or larger than a second critical current, the second spin orbit torque current is larger than the first critical current and smaller than the second critical current, and the first critical current and the second critical current are determined according to the intensity of the externally-applied magnetic field and the intensity of the DMI effect.

Preferably, when the spin-orbit coupling layer inputs a first spin-orbit torque current in a forward direction, the resistance state of the magnetic tunnel junction is a first resistance state, and when the spin-orbit coupling layer inputs a first spin-orbit torque current in a reverse direction, the resistance state of the magnetic tunnel junction is a second resistance state.

Preferably, the magnetic tunnel junction is elliptical, and the first spin orbit torque current comprises a first current input along a length or width direction of the spin orbit coupling layer;

the second spin orbit torque current includes a second current input along the major or minor axis of the ellipse.

Preferably, the length direction of the spin-orbit coupling layer comprises a first direction and a second direction which are opposite, and the width direction comprises a third direction and a fourth direction which are opposite;

the second current is obtained by compounding the sub-current input along the first direction or the second direction and the sub-current input along the third direction or the fourth direction.

Preferably, the first and second liquid crystal materials are,

the storage unit comprises a magnetic field generating device for providing the external magnetic field or equivalently providing the external magnetic field; alternatively, the first and second electrodes may be,

the magnetic tunnel junction comprises a fixed layer, a barrier layer and a free layer which are sequentially arranged from top to bottom, wherein the section of at least one of the fixed layer, the barrier layer and the free layer is trapezoidal and is used for providing the external magnetic field; alternatively, the first and second electrodes may be,

the spin orbit coupling layer is made of an antiferromagnetic material, and forms an exchange bias field with the free layer and is used for providing the external magnetic field; alternatively, the first and second electrodes may be,

the magnetic tunnel junction comprises a magnetic material layer for providing the externally applied magnetic field; alternatively, the first and second electrodes may be,

the magnetic tunnel junction has a shape capable of forming a shape anisotropy field for providing an equivalent magnetic field of the externally applied magnetic field; alternatively, the free layer has a perpendicular anisotropy of gradient for providing an equivalent magnetic field to the externally applied magnetic field.

Preferably, the DMI effect has an intensity of 0.1-3mJ/m²。

Preferably, the device further comprises a control circuit;

the control circuit is used for reading the resistance state of the magnetic tunnel junction, determining whether the resistance state of the magnetic tunnel junction needs to be changed or not according to the resistance state of the magnetic tunnel junction and the data to be written, and if yes, inputting a second current to the spin orbit coupling layer to change the resistance state of the magnetic tunnel junction so as to write the data to be written.

The invention also discloses a multifunctional magnetic random access memory which comprises a plurality of multifunctional magnetic random access memory units arranged in an array.

The invention also discloses a computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor,

the processor and/or the memory comprise a multifunctional magnetic random access memory unit as described above.

The invention sets an external magnetic field in the multifunctional magnetic random access memory and enables the free layer of the magnetic tunnel junction to be under the action of DMI effect. Under the input condition of spin orbit torque currents with different current densities (current magnitudes), the spin orbit coupling layer A1 is subjected to main effects of different effects, when a first spin orbit torque current is input, the effect of an external magnetic field applied to the magnetic tunnel junction is larger than the effect of a DMI effect or due to asymmetry of writing, the magnetic tunnel junction can realize bipolar inversion of a free layer under the effect of the first spin orbit torque currents in different directions, and the magnetic tunnel junction can be used for a data writing process. When the spin orbit coupling layer inputs the second spin orbit torque current, the action of an external magnetic field applied to the magnetic tunnel junction is smaller than the action of the DMI effect, and unipolar inversion of the free layer can be realized under the action of the second spin orbit torque current, so that the spin orbit coupling layer can be applied to the logic operation process.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a block diagram of one embodiment of a multi-functional magnetic random access memory cell of the present invention;

FIG. 2 illustrates a resistance state change diagram of a magnetic tunnel junction as a function of current density for one embodiment of the multi-functional magnetic random access memory cell of the present invention;

FIG. 3 is a schematic diagram of the input spin orbit torque current along the length or width of the spin orbit coupling layer for one embodiment of the multi-functional magnetic random access memory cell of the present invention;

FIG. 4 is a diagram illustrating the input of spin orbit torque current along the minor axis of an ellipse for one embodiment of the multi-functional MRAM cell of the present invention;

FIG. 5 is a schematic diagram of an elliptical magnetic tunnel junction in accordance with one embodiment of the present invention;

FIG. 6 illustrates a schematic block diagram of a computer device suitable for use in implementing embodiments of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In accordance with one aspect of the present invention, the present embodiment discloses a multifunctional magnetic random access memory cell. As shown in fig. 1, in this embodiment, the multifunctional Magnetic random access memory cell includes a spin-orbit coupling layer a1, at least one Magnetic Tunnel Junction (MTJ) disposed on the spin-orbit coupling layer a1, and an applied Magnetic field, wherein a free layer B1 of the at least one MTJ is subject to a DMI (dzyalshinskii-moriyan interaction) effect.

It should be noted that the DMI effect is an interface effect, and can cause non-parallel alignment of magnetic moments, i.e., cause non-uniform distribution of magnetic moments. In practical production, the free layer B1 can be affected by the DMI effect by controlling the process of the magnetic tunnel junction free layer B1 and providing an insertion layer, resulting in an uneven distribution of magnetic moment. Wherein the upper surface and/or the lower surface of the free layer B1 may be subject to the DMI effect. Specifically, the lower surface of the free layer B1 in contact with the spin-orbit coupling layer a1 may be subjected to the DMI effect, and the upper surface of the free layer B1 in contact with the barrier layer B2 or the insertion layer may also be subjected to the DMI effect. For example, the free layer B1 may be affected by the DMI effect by controlling the annealing temperatures of the top and bottom surfaces of the free layer B1 or by adding Mg insertion layers. In practical applications, the DMI effect to which the free layer B1 is subjected can be set by those skilled in the art according to practical requirements, and will not be described herein again.

When a first spin orbit torque current is input into the spin orbit coupling layer A1, the action of an external magnetic field applied to the magnetic tunnel junction is greater than the action of a DMI effect, and the resistance state of the magnetic tunnel junction corresponds to the direction of the spin orbit torque current; when a second spin orbit torque current is input to the spin orbit coupling layer a1, the magnetic tunnel junction is subjected to an applied magnetic field less than the DMI effect, and the resistance state of the magnetic tunnel junction changes.

The invention sets an external magnetic field in the multifunctional magnetic random access memory and leads the free layer B1 of the magnetic tunnel junction to be subjected to the action of DMI effect. Under the input condition of spin orbit torque currents with different current densities (current magnitudes), the spin orbit coupling layer A1 is subjected to main effects of different effects, when a first spin orbit torque current is input, the effect of an external magnetic field applied to the magnetic tunnel junction is larger than the effect of a DMI effect, or due to the asymmetry of writing critical currents corresponding to different resistance states of the magnetic tunnel junction, the magnetic tunnel junction can realize the bipolar inversion of the free layer B1 under the effect of the first spin orbit torque currents in different directions, and the magnetic tunnel junction can be used for a data writing process. In the process, the external magnetic field plays a main role in the magnetic moment overturning of the magnetic tunnel junction. When the spin orbit coupling layer A1 inputs the second spin orbit torque current, the action of the external magnetic field applied to the magnetic tunnel junction is smaller than the action of the DMI effect, and the unipolar inversion of the free layer B1 can be realized under the action of the second spin orbit torque current, so that the free layer B1 can be applied to the logic operation process. In this process, the DMI effect plays a major role in the magnetic moment flipping of the magnetic tunnel junction.

In a preferred embodiment, the first spin orbit torque current is less than a first critical current, the second spin orbit torque current is greater than a first critical current and less than a second critical current, and the first critical current and the second critical current are determined according to the strength of the applied magnetic field and the strength of the DMI effect.

It is understood that, as shown in fig. 2, it is experimentally verified that the effect of the applied magnetic field and the DMI effect on the magnetic tunnel junction free layer B1 is different as the current density of the spin orbit torque current is increased. Therefore, the first critical current and the second critical current can be determined according to the change condition of the resistance state of the magnetic tunnel junction under the input condition of the spin orbit torque current with different current densities. When the first spin orbit torque current input into the spin orbit coupling layer a1 is smaller than the first critical current, due to the asymmetry of the critical current written by different initial data, or the action of an external magnetic field applied to the magnetic tunnel junction is larger than the action of the DMI effect, the magnetic tunnel junction can realize bipolar inversion at the moment, so that the final resistance state of the magnetic tunnel junction corresponds to the direction of the first spin orbit torque current, the writing of deterministic data can be realized, and the complexity of the writing operation is reduced.

However, when the second spin orbit torque current input to the spin orbit coupling layer a1 is greater than the first critical current and less than the second critical current, the effect of the applied magnetic field applied to the magnetic tunnel junction is less than the effect of the DMI effect, so that the magnetic tunnel junction can only perform unipolar switching at this time, and the resistance state of the magnetic tunnel junction changes when the second spin orbit torque current is input. That is, if the original resistance state of the magnetic tunnel junction is a high resistance state, the resistance state of the magnetic tunnel junction is changed into a low resistance state after the second spin orbit torque current is input; if the original resistance state of the magnetic tunnel junction is a low resistance state, the resistance state of the magnetic tunnel junction is changed into a high resistance state after the second spin orbit torque current is input. Therefore, when the second spin orbit torque current is input, the resistance state change of the magnetic tunnel junction can be realized, namely, one-time 'NOT' logic operation is performed on the data stored in the magnetic tunnel junction, so that the magnetic tunnel junction can be applied to various logic operations and used as a logic device. In summary, by determining the first critical current and the second critical current of the multifunctional mram, different requirements of unipolar inversion and bipolar inversion can be achieved by controlling the current direction and the current density of the spin-orbit torque current input to the spin-orbit coupling layer a1, so that the mram can be applied to various application scenarios such as data writing and logic operation.

In a preferred embodiment, the first spin orbit torque current is greater than a second critical current, the second spin orbit torque current is greater than a first critical current and less than a second critical current, and the first critical current and the second critical current are determined according to the strength of the applied magnetic field and the strength of the DMI effect.

It is to be understood that, referring again to the experimental verification result of fig. 2, when the current density of the spin orbit torque current input to the spin orbit coupling layer a1 is greater than the second critical current, the bipolar switching of the magnetic tunnel junction can be also achieved, so that in the preferred embodiment, the deterministic writing of data can also be achieved by making the input first spin orbit torque current greater than the second critical current. In practical applications, the first spin orbit torque current may be selected from a current density range smaller than the first critical current, and may also be selected from a current density range larger than the second critical current, which can be determined by those skilled in the art according to practical requirements, and the present invention is not limited thereto.

It is understood that the first spin orbit torque current is less than a first critical current or greater than a second critical current, the second spin orbit torque current is greater than the first critical current and less than the second critical current, and the first critical current and the second critical current are determined according to the strength of the applied magnetic field and the strength of the DMI effect. Referring again to the experimental verification results of fig. 2, the first spin orbit torque current input to the spin orbit coupling layer a1 can be selected in a current range smaller than the first critical current and larger than the second critical current based on a similar principle.

In a preferred embodiment, as shown in fig. 1, when the spin orbit coupling layer a1 inputs the first spin orbit torque current in the forward direction, the resistance state of the magnetic tunnel junction is the first resistance state, and when the spin orbit coupling layer a1 inputs the first spin orbit torque current in the reverse direction, the resistance state of the magnetic tunnel junction is the second resistance state.

It is understood that the final resistance state of the magnetic tunnel junction is deterministically changed by controlling the difference in direction of the first spin orbit torque current. That is, in the preferred embodiment, when the first spin orbit torque current in the forward direction is input to the spin orbit coupling layer a1, the resistance state of the magnetic tunnel junction changes to the first resistance state, and when the first spin orbit torque current in the reverse direction is input to the spin orbit coupling layer a1, the resistance state of the magnetic tunnel junction changes to the second resistance state. According to different structures of the magnetic tunnel junction, the first resistance state can be a high resistance state, and the corresponding second resistance state is a low resistance state; the first resistance state may also be a low resistance state, and the corresponding second resistance state is a high resistance state. In practical application, the correspondence between the direction of the first spin orbit torque current and the resistance state of the magnetic tunnel junction can be realized by changing the structure of the magnetic tunnel junction, adding a peripheral circuit and the like, which is not limited by the invention.

In a preferred embodiment, the magnetic tunnel junction is circular, as shown in FIG. 1. Wherein, Hex is the field intensity direction of the external magnetic field. The spin-orbit coupling layer has a length direction including a first direction and a second direction opposite to each other, such as a C3, C5 node shown in fig. 5, and a width direction including a third direction and a fourth direction opposite to each other, such as a C2, C4 node shown in fig. 5. The first spin orbit torque current includes a first current input in a length or width direction of the spin orbit coupling layer. The second spin orbit torque current includes a second current input in a length or width direction of the spin orbit coupling layer.

It is understood that when the spin-orbit coupling layer inputs the first spin-orbit torque current, the magnetic moment of the free layer of the magnetic tunnel junction is subjected to bipolar switching. That is, assuming that the first spin orbit torque current is input to the spin orbit coupling layer along the first direction C3 or the third direction C2, the resistance state of the magnetic tunnel junction is finally the first resistance state. When the first spin-orbit torque current is input to the spin-orbit coupling layer along the second direction C5 or the fourth direction C4, the resistance state of the magnetic tunnel junction is finally the second resistance state, so that the bipolar inversion can be realized. Specifically, the current directions of the first sub-current of the first direction and the second sub-current of the second direction input to the spin orbit coupling layer a1 are opposite, so that it is assumed that the final resistance state of the magnetic tunnel junction is the first resistance state when the first sub-current is input to the spin orbit coupling layer a1 in the first direction. The final resistance state of the magnetic tunnel junction is the second resistance state when the first sub-current is input to the spin orbit coupling layer a1 in the second direction opposite to the first direction. Similarly, the current directions of the second sub-current of the third direction and the second sub-current of the fourth direction input to the spin orbit coupling layer a1 are opposite, so that it is assumed that the final resistance state of the magnetic tunnel junction is the first resistance state when the second sub-current is input to the spin orbit coupling layer a1 in the third direction. Then when a second sub-current is input to the spin-orbit coupling layer a1 in a fourth direction opposite to the third direction, the final resistance state of the magnetic tunnel junction is the second resistance state, and bipolar switching can be achieved.

When the spin orbit coupling layer inputs second spin orbit torque current, the magnetic torque of the free layer of the magnetic tunnel junction is subjected to unipolar overturning. That is, when the second spin orbit torque current is input to the spin orbit coupling layer along the first direction C3, the third direction C2, the second direction C5, or the fourth direction C4, the resistance state of the magnetic tunnel junction changes to the second resistance state, and unipolar switching can be achieved.

It will be appreciated that the externally applied magnetic field needs to be collinear with the first spin orbit torque current in order to achieve deterministic writing of data. The direction of the magnetic field can be determined by a person skilled in the art on the basis of common general knowledge, and the invention will not be described in detail here.

In a preferred embodiment, the magnetic tunnel junction is elliptical, as shown in FIG. 5. The length direction of the spin orbit coupling layer comprises a first direction and a second direction which are opposite, such as a C3 node and a C5 node, and the width direction comprises a third direction and a fourth direction which are opposite, such as a C2 node and a C4 node. The first spin orbit torque current includes a first current input in a length or width direction of the spin orbit coupling layer a 1. The second spin orbit torque current includes a second current along both ends of the major or minor axis of the ellipse.

It is to be understood that, in general, the first spin orbit torque current and the second spin orbit torque current may be input in the length or width direction of the spin orbit coupling layer a 1. And when the magnetic tunnel junction is a tilted non-fully symmetric structure, such as an ellipse, as shown in fig. 3, a single polarity inversion of the magnetic tunnel junction can be achieved by applying a unidirectional current, i.e., a second spin orbit torque current, along the major or minor axis of the ellipse, and this unidirectional current can be achieved by a combination of a first sub-current input along the first or second direction and a second sub-current input along the third or fourth direction. As shown in fig. 4, the first spin orbit torque current may select one of the first sub-current input in the first direction or the second direction and the second sub-current input in the third direction or the fourth direction to be input to the spin orbit coupling layer a 1. For example, as shown in fig. 3, when a sub-current is input to the spin orbit coupling layer a1 through the first direction and the second direction, the final resistance state of the magnetic tunnel junction is the first resistance state. Then, when a sub-current is input to the spin orbit coupling layer a1 through the third direction and the fourth direction, the final resistance state of the magnetic tunnel junction is the second resistance state.

It is understood that the inhomogeneous demagnetizing field in the elliptical structure, i.e. the shape anisotropy field, can be used as an equivalent magnetic field, and thus no other means for applying a magnetic field is required. It is understood that in the bipolar writing section in the present embodiment, the effect of the equivalent magnetic field due to the inhomogeneous demagnetizing field still needs to be larger than that of the DMI effect, that is, in line with the foregoing analysis. When the effect of the equivalent magnetic field due to the inhomogeneous demagnetizing field is smaller than that of the DMI effect, unipolar writing can still occur in the magnetic tunnel junction. It is understood that in the unipolar writing scheme in the present embodiment, the inhomogeneous demagnetizing field is not effective for the composite current along the major and minor axes, and the DMI effect plays a major role at this time, and thus is a unipolar writing scheme.

It is understood that, for the oval magnetic tunnel junction, the second current forming the second spin orbit torque current may be formed by recombination of sub-currents input in the length or width direction of the spin orbit coupling layer a 1. Specifically, the length and width directions of the spin-orbit coupling layer a1 include four input directions from the first direction to the fourth direction, and the sub-currents in two adjacent directions can be combined to form an oblique current along the central line direction of the two directions, so that the first sub-current to the fourth sub-current can be combined to form a second current input along the major axis and the minor axis of the ellipse.

In alternative embodiments, the externally applied magnetic field in the multi-functional magnetic random access memory cell can be achieved in a variety of ways. Specifically, the externally applied magnetic field may be formed by at least one of the following:

the storage unit comprises a magnetic field generating device for providing the external magnetic field or equivalently providing the external magnetic field;

the magnetic tunnel junction comprises a fixed layer B3, a barrier layer B2 and a free layer B1 which are sequentially arranged from top to bottom, wherein the section of at least one of the fixed layer B3, the barrier layer B2 and the free layer B1 is trapezoidal, and the fixed layer B3, the barrier layer B2 and the free layer B1 are used for providing the external magnetic field;

the spin-orbit coupling layer A1 is made of antiferromagnetic material, the spin-orbit coupling layer A1 forms an exchange bias field with the free layer B1 for providing the externally applied magnetic field;

the magnetic tunnel junction includes a layer of magnetic material (e.g., a Co layer) for providing the externally applied magnetic field;

the magnetic tunnel junction has a shape capable of forming a shape anisotropy field (inhomogeneous demagnetization field) for providing the external magnetic field. In some embodiments, the magnetic tunnel junction may have a rectangular shape, an elliptical shape, an isosceles right-angle shape, etc., and taking the elliptical shape as an example, the demagnetization field in the major axis direction is weak and in the minor axis direction, and the demagnetization field may be equivalent to an external magnetic field;

the free layer B1 has a perpendicular anisotropy of gradient to provide a magnetic field equivalent to the externally applied magnetic field. Specifically, when the magnetic tunnel junction is manufactured, the concentration of the target material can be adjusted, so that the free layer B1 has the vertical anisotropy of the gradient, the symmetry of the magnetic moment distribution is further broken, and the magnetic tunnel junction can be used for providing an equivalent external magnetic field. At this time, the free layer B1 can still be affected by interface interaction such as DMI effect and other applied magnetic fields.

It should be noted that the magnetic field generating device or the equivalent device capable of forming the external magnetic field is a conventional technical means in the art, and those skilled in the art can flexibly set the device according to the needs, and details are not described herein. In addition, an applied magnetic field may be provided by forming at least one of the pinned layer B3, the barrier layer B2, and the free layer B1 to have a trapezoidal cross section, forming an exchange bias field with the free layer B1 using an antiferromagnetic material, providing a magnetic material layer, or the like. In practical applications, the applied magnetic field may be formed by other feasible manners, which is not limited by the present invention.

In a preferred embodiment, the magnetic tunnel junction includes a fixed layer B3, a barrier layer B2, and a free layer B1, which are sequentially disposed from top to bottom. The bottom surface of the free layer B1 is fixedly connected to the spin-orbit coupling layer A1. It is understood that the resistance of the magnetic tunnel junction depends on the magnetization directions of the pinned layer B3 and the free layer B1, while the magnetization directions of the free layer B1 and the pinned layer B3 are determined by the magnetic moment directions. When the magnetic moment directions of the pinned layer B3 and the free layer B1 are the same, the magnetic tunnel junction is in a low resistance state (low resistance state), and when the magnetic moment directions of the pinned layer B3 and the free layer B1 are opposite, the magnetic tunnel junction is in a high resistance state (high resistance state). The high resistance state and the low resistance state of the magnetic tunnel junction may be respectively associated with different data in advance, for example, it is preset that the high resistance state corresponds to data "1" and the low resistance state corresponds to data "0", a current or a voltage is input to the magnetic tunnel junction through the read circuit, the resistance state of the magnetic tunnel junction may be determined to be the resistance state of the high resistance state or the low resistance state according to a change in the current or the voltage, and the data stored in the magnetic tunnel junction may be determined to be "1" or "0" according to the resistance state of the magnetic tunnel junction. The ranges of the high resistance state and the low resistance state are determined by common technical means in the art, and those skilled in the art can determine the resistance ranges of the high resistance state and the low resistance state of the magnetic tunnel junction according to common knowledge, which is not described herein again.

In a preferred embodiment, the magnetic tunnel junction may further include at least one of layer structures of an insertion layer, a pinning layer, a seed layer, and a capping layer in order to adjust characteristics of perpendicular anisotropy of the magnetic tunnel junction, smoothness of each layer, and a DMI effect, etc. One or more layers of structures can be arranged according to actual requirements, and a person skilled in the art can arrange the magnetic tunnel junction structures in a top-down arrangement order according to the requirements, which is not limited in the present invention. For example, in one specific example, a 0.1nm-1nm Mg layer may be interposed between the free layer B1 and the spin-orbit coupling layer A1, or a 0.1nm-1nm Mg layer may be interposed between the free layer B1 and the barrier layer B2 to increase the strength of the DMI effect to which the free layer B1 is subjected.

In a preferred embodiment, the strength of the DMI effect to which the free layer B1 is subjected can be set to 0.1 to 3mJ/m by controlling the process conditions of the free layer B1 or providing an insertion layer, etc²Within the range of (1). In order to better realize the multiple functions of random number generation and data writing of the multifunctional magnetic random memory cell of the invention, the strength of the DMI effect to which the magnetic tunnel junction free layer B1 is subjected is preferably 0.1-2mJ/m²Within the range to prevent oscillation effects caused by excessive DMI effects. More preferably, the strength of the DMI effect to which the magnetic tunnel junction free layer B1 is subjected is 0.1-1.5mJ/m²Within the range.

Alternatively, the shape of the magnetic tunnel junction on the spin orbit coupling layer a1 may be any one of a cube, a cylinder, a cube, or an elliptical cylinder. The bottom surface shape of at least one magnetic tunnel junction provided on the spin orbit coupling layer a1, that is, the lower surface of the free layer B1 is coupled with the spin orbit coupling layer a 1.

Preferably, the spin orbit coupling layer a1 may be selected to have a rectangular shape such that the top surface area of the spin orbit coupling layer a1 is larger than the area occupied by the at least one magnetic tunnel junction provided on the spin orbit coupling layer a1, even though the at least one magnetic tunnel junction may be provided on the spin orbit coupling layer a1 with the outer edge of the at least one magnetic tunnel junction located inside the outer edge of the spin orbit coupling layer a 1. Among them, the spin orbit coupling layer a1 can be preferably selected from a heavy metal strip film or an antiferromagnetic strip film.

It should be noted that, one or more magnetic tunnel junctions on the spin-orbit coupling layer a1 may be provided, and preferably, a plurality of magnetic tunnel junctions may be provided on the same spin-orbit coupling layer a1, so that one-time data writing operation to the plurality of magnetic tunnel junctions can be realized, the number of control transistors to which the first current or the second current is input can be reduced, and thus, the integration level is improved and the power consumption of the circuit is reduced.

In a preferred embodiment, the magnetic random access memory cell can be input with current to the spin-orbit coupling layer A1 and the magnetic tunnel junction by placing electrodes on the spin-orbit coupling layer A1 and the magnetic tunnel junction, such as a top electrode on top of the magnetic tunnel junction and an input electrode and an output electrode on opposite sides of the spin-orbit coupling layer A1, respectively. Among them, the material of the electrode is preferably tantalum Ta, aluminum Al, gold Au, or copper Cu.

Preferably, the material of the free layer B1 and the fixed layer B3 may be ferromagnetic metal, and the material of the barrier layer B2 may be oxide. The magnetic tunnel junction has perpendicular magnetic anisotropy, which means that the magnetization directions of the free layer B1 and the pinned layer B3 forming the magnetic tunnel junction are in the perpendicular direction. The ferromagnetic metal can be a mixed metal material formed by at least one of cobalt iron CoFe, cobalt iron boron CoFeB or nickel iron NiFe, and the proportion of the mixed metal materials can be the same or different. The oxide can be magnesium oxide MgO or aluminum oxide Al₂O₃And one of the oxides is used for generating tunneling magnetoresistance effect. In practical applications, the ferromagnetic metal and the oxide may be made of other feasible materials, and the invention is not limited to this.

The free layer B1 of the magnetic tunnel junction is fixedly contacted with the spin orbit coupling layer A1, each layer of the magnetic tunnel junction and the spin orbit coupling layer A1 can be sequentially plated on the substrate from bottom to top by the traditional methods of ion beam epitaxy, atomic layer deposition or magnetron sputtering and the like, and then a plurality of magnetic tunnel junctions are prepared and formed by the traditional nanometer device processing technologies of photoetching, etching and the like.

In a preferred embodiment, the spin-orbit coupling layer a1 is a spin-orbit coupling layer a1 made of a heavy metal film, an antiferromagnetic film, or other material. The heavy metal film or the antiferromagnetic film can be made into a rectangle, the top area of the heavy metal film or the antiferromagnetic film is preferably larger than the bottom area of the outline formed by all the magnetic tunnel junctions so as to be capable of arranging one or more magnetic tunnel junctions, and the bottom shapes of the magnetic tunnel junctions are completely embedded into the top shapes of the heavy metal film or the antiferromagnetic film. Preferably, the material of the spin-orbit coupling layer a1 may be one of platinum Pt, tantalum Ta, or tungsten W. In practical applications, the spin-orbit coupling layer a1 may be formed by other feasible materials, which is not limited by the invention.

In this embodiment, the magnetic tunnel junction includes a top pinned layer B3, a free layer B1 in contact with the spin-orbit coupling layer a1, and a barrier layer B2 disposed between the pinned layer B3 and the free layer B1, and is a three-layer structure including only one free layer B1. In other embodiments, the free layer B1 may be provided in plurality, i.e., two or more free layers B1. The magnetic tunnel junction includes a top fixed layer B3, a plurality of free layers B1, and a barrier layer B2 disposed between each adjacent two layers, the lowermost free layer B1 being disposed in contact with the spin-orbit coupling layer a 1. For example, in a specific example, when two free layers B1 are included, the magnetic memory cell structure may include a spin-orbit coupling layer a1, a second free layer B1, a barrier layer B2, a first free layer B1, a barrier layer B2, and a fixed layer B3, which are sequentially disposed on the spin-orbit coupling layer a 1.

In a preferred embodiment, the multi-functional magnetic random access memory cell further comprises a control circuit. The control circuit is used for reading the resistance state of the magnetic tunnel junction, determining whether the resistance state of the magnetic tunnel junction needs to be changed or not according to the resistance state of the magnetic tunnel junction and the data to be written, and if yes, inputting a second current to the spin orbit coupling layer to change the resistance state of the magnetic tunnel junction so as to write the data to be written. Wherein the control circuit can read the resistance state of the magnetic tunnel junction through the terminal C1.

It will be appreciated that when the spin orbit coupling layer inputs the second spin orbit torque current, the resistance state of the magnetic tunnel junction changes, i.e., the resistance state in the magnetic tunnel junction changes to the opposite resistance state, causing the data stored in the magnetic tunnel junction to change from one data to another. For example, when the resistance state of the magnetic tunnel junction is a high resistance state or a low resistance state, it indicates that two data "1" and "0" are stored in the magnetic tunnel junction, respectively. Then the resistance state of the magnetic tunnel junction becomes to represent that the stored data is "0" through the writing of the second spin orbit torque current when the resistance state of the magnetic tunnel junction represents that the stored data is "1". Vice versa, when the resistance state of the magnetic tunnel junction indicates that the stored data is "0", the resistance state of the magnetic tunnel junction changes to indicate that the stored data is "1" through writing by the second spin orbit torque current. Therefore, when data writing is performed, it is preferable that the resistance state of the magnetic tunnel junction be determined first by the control circuit to determine the data stored in the magnetic tunnel junction. Further, whether the data stored in each magnetic tunnel junction needs to be changed or not can be determined according to the data to be written and the data stored in the current magnetic tunnel junction so as to determine whether the resistance state of the magnetic tunnel junction is changed by inputting the second spin orbit torque current or not, and the data stored in the magnetic tunnel junction is the data to be written. It should be noted that the specific circuit structure design of the control circuit is a conventional technical means in the art, and those skilled in the art can implement the function of the control circuit by using different circuit structures according to actual needs, which is not described herein again.

Based on the same principle, the embodiment also discloses a multifunctional magnetic random access memory. The multi-functional magnetic random access memory comprises a plurality of multi-functional magnetic random access memory cells arranged in an array.

Multifunctional magnetic random access memory, including permanent and non-permanent, removable and non-removable media, may implement any method or technology for storing information. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of applications for the multifunction magnetic random access memory include, but are not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device.

The problem solving principle of the multifunctional magnetic random access memory is similar to that of the multifunctional magnetic random access memory unit, so the implementation of the multifunctional magnetic random access memory can refer to the implementation of the multifunctional magnetic random access memory unit, and is not described herein again.

Based on the same principle, the embodiment also discloses a computer device which comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor.

The processor and/or the memory comprise a multifunctional magnetic random access memory unit as described in this embodiment.

The multifunctional magnetic random access memory unit illustrated in the above embodiments may be specifically configured in a product device having a certain function. A typical implementation device is a computer device, which may be, for example, a personal computer, a laptop computer, a cellular telephone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

In a typical example the computer arrangement comprises in particular a memory, a processor and a computer program stored on the memory and executable on the processor, said processor and/or said memory comprising a multifunctional magnetic random access memory unit as described in the present embodiment.

Referring now to FIG. 6, shown is a schematic diagram of a computer device 600 suitable for use in implementing embodiments of the present application.

As shown in fig. 6, the computer apparatus 600 includes a Central Processing Unit (CPU)601 which can perform various appropriate works and processes according to a program stored in a Read Only Memory (ROM)602 or a program loaded from a storage section 608 into a Random Access Memory (RAM)) 603. In the RAM603, various programs and data necessary for the operation of the system 600 are also stored. The CPU601, ROM602, and RAM603 are connected to each other via a bus 604. An input/output (I/O) interface 605 is also connected to bus 604.

The following components are connected to the I/O interface 605: an input portion 606 including a keyboard, a mouse, and the like; an output section 607 including a Cathode Ray Tube (CRT), a liquid crystal feedback (LCD), and the like, and a speaker and the like; a storage section 608 including a hard disk and the like; and a communication section 609 including a network interface card such as a LAN card, a modem, or the like. The communication section 609 performs communication processing via a network such as the internet. The driver 610 is also connected to the I/O interface 605 as needed. A removable medium 611 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like is mounted on the drive 610 as necessary, so that a computer program read out therefrom is mounted as necessary on the storage section 608.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The application may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The application may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.