A spin logic device based on vertical exchange bias and its control method

Abstract

The present invention belongs to the field of magnetic devices, specifically a spin logic device based on perpendicular exchange bias and its control method. The present invention uses a ferromagnetic / antiferromagnetic bilayer perpendicular exchange bias structure to prepare a spin logic device. The spin-orbit moment effect is utilized to generate a spin-polarized current in the heavy metal layer by inputting a current, thereby modulating the exchange bias field in the ferromagnetic layer / antiferromagnetic bilayer film. By testing the anomalous Hall voltage in the structure and coordinating the change in the magnitude of the spin-orbit moment injection current along the long axis of the unit, AND gate, NAND gate, OR gate, NOR gate, and NOT gate logic are realized. The present invention not only realizes a new type of spin logic device based on antiferromagnetic materials, but also has the advantages of stronger resistance to external magnetic field interference, low switching current density, simple structure, and compatibility with MRAM process.

Description

Technical Field

[0001] The present invention belongs to the field of magnetic devices, specifically a spin logic device based on perpendicular exchange bias and a control method thereof, which utilizes the spin-orbit moment effect to modulate the exchange bias field in the ferromagnetic layer / antiferromagnetic bilayer film to realize AND gate, NAND gate, OR gate, NOR gate, and NOT gate logic units. Background Art

[0002] Based on the spin-orbit moment driving the magnetic moment reversal of the magnetic layer, this device has the advantages of fast writing speed, low power consumption, high durability, and non-volatility. It can be used as a random access memory (MRAM) and can also be used to implement logic devices. In the implementation process of this type of logic device, because it uses the electron spin effect, it is also called a spin logic device.

[0003] In current spin logic cells, a current is typically passed through a metal layer with strong spin-orbit coupling, generating a spin-polarized current perpendicular to the direction of the current. This current flows into the ferromagnetic layer, exerting a torque on the ferromagnetic layer, causing it to flip. This flipped state can be characterized by the potential difference between the two ends, perpendicular to the direction of the injected current. This principle exploits the anomalous Hall effect. Therefore, by controlling the magnetization direction through spin-orbit driven current and characterizing it with the anomalous Hall voltage, spin logic devices can be constructed using this principle.

[0004] Generally speaking, for a magnetic film with perpendicular anisotropy, two different anomalous Hall voltage values ​​can be obtained when the magnetic moment is oriented in the positive direction perpendicular to the film surface and in the negative direction perpendicular to the film surface. In general, when the magnetic moment perpendicular to the film surface is all along the positive direction, a maximum voltage V1 is obtained, and when the magnetic moment perpendicular to the film surface is all along the negative direction, a minimum voltage V2 is obtained. Generally, a judgment voltage V is set. th , When the abnormal Hall voltage value of the unit is greater than V th When the abnormal Hall voltage value of the unit is less than V th Based on this, the desired logic output can be achieved by simply changing the magnetic moment state when the input current of the gate device meets certain conditions and obtaining different anomalous Hall voltages.

[0005] Currently, most common spin logic devices use spin-orbit torque to drive the flipping of ferromagnetic materials. This method has disadvantages such as excessively high switching current density and weak resistance to external interference. Summary of the Invention

[0006] To address the aforementioned problems and shortcomings, and to address the issues of excessively high switching current density and low resistance to external interference in existing spin logic devices, the present invention provides a spin logic device based on perpendicular exchange bias and a control method thereof. Based on the spin-orbit moment effect, an input current generates a spin-polarized current in the heavy metal layer, thereby changing the exchange bias direction of the ferromagnetic / antiferromagnetic bilayer and ultimately driving the magnetic moment of the ferromagnetic layer to flip. By testing the anomalous Hall voltage in the structure and adjusting the magnitude of the spin-orbit moment injection current along the long axis of the cell (the X-axis), gate logic is ultimately achieved.

[0007] The spin-orbit torque-driven unit adopted in the present invention is a ferromagnetic / antiferromagnetic double-layer structure, which has a simple overall structure and is easy to prepare. The spin-orbit torque drives the magnetic moments of the ferromagnetic layer and the antiferromagnetic layer. Therefore, the logic storage method realized by this method will have a lower driving current density and anti-interference ability.

[0008] The technical solutions of the present invention are as follows:

[0009] A spin logic device based on perpendicular exchange bias has a structure from bottom to top of: injection polarization layer / ferromagnetic layer / antiferromagnetic layer / cover layer. The spin logic unit is a double-layer magnetic film of ferromagnetic layer / antiferromagnetic layer, and the exchange bias structure of the magnetic film exhibits out-of-plane anisotropy, that is, the magnetic moment of the magnetic film is oriented along the out-of-plane direction.

[0010] The injection polarization layer (ie, the spin-orbit moment current injection layer) is a cross-shaped thin film made of heavy metal materials with spin-orbit coupling, such as Ta, W, Pt, etc., and its thickness is less than the spin diffusion length of the injection polarization layer material.

[0011] The center point of the cross-shaped injection polarization flow layer is the origin of the coordinate system. The direction perpendicular to the film surface is the positive Z-axis, and the two mutually perpendicular sides of the cross are the X-axis and Y-axis, respectively. Two current pulse input terminals A and B are set in the negative direction of the X-axis, and an output terminal is set in the positive direction of the X-axis, with current flowing from the negative direction of the X-axis to the positive direction of the X-axis. Positive and negative test points for the anomalous Hall voltage are set in the positive and negative directions of the Y-axis of the injection polarization flow layer.

[0012] The magnetic film (ferromagnetic layer / antiferromagnetic layer) is positioned on the X-axis such that its physical center overlaps the origin of the injection polarization layer. The long axis of the magnetic film is along the X-axis, and the short axis is along the Y-axis. The width of the magnetic film is consistent with the X-axis width of the injection polarization layer. The Y-axis width of the injection polarization layer is ≤ its length ≤ its X-axis length.

[0013] The ferromagnetic layer material is selected from CoFeB, CoFe and / or Co.

[0014] The antiferromagnetic material is selected from IrMn, FeMn and / or PtMn.

[0015] The cover layer is disposed on the magnetic film in a completely covering manner to protect the spin logic unit, and Ta or Cu may be used.

[0016] The methods for controlling the magnetic moment of the above-mentioned spin logic device are:

[0017] In order to achieve the control of the magnetic moment of the device, the polarization layer is injected with a current pulse along the positive direction of the X axis. In the present invention, two current pulses I A and I B As the two inputs of the gate device, they correspond to input terminal A and input terminal B (such as Figure 1 When realizing the corresponding gate logic device, it is necessary to apply the corresponding auxiliary magnetic field H in the X axis (the long axis direction of the entire magnetic film). f ; Among them H f A positive value indicates that the magnetic field is along the positive direction of the X axis, H f Negative indicates that the magnetic field is in the negative direction of the X axis, H f The positive or negative value of is determined by the selected injection polarization flow layer material; when the spin Hall angle of the selected heavy metal material is positive, such as Pt, the selected H f <0; When the spin Hall angle of the selected heavy metal material is negative, such as Ta, W, etc., the selected H f >0; to meet the requirement of spin-orbit torque driving the reversal of the perpendicular magnetic moment of ferromagnetic and antiferromagnetic materials.

[0018] The two input logic states of the gate circuit "1" and "0" correspond to the input of a large current pulse I L and a small current pulse I S (I L >I S , determined by the selected material and structure), I L and I S Size and H f The direction and magnitude of the spin-orbit moment need to be determined according to the following rules for the magnetization reversal of the ferromagnetic layer / antiferromagnetic layer: V th is the set judgment voltage.

[0019] Rule 1: If the initial orientation of the magnetic moment of the magnetic film is along the negative direction of the Z axis (the anomalous Hall voltage output at the output end is V2), the applied auxiliary magnetic field H f Along the X-axis, and |H f |<|H i |, where H i The applied current is I L +I SThe magnetic field required for half of the magnetic moments of the ferromagnetic layer and the antiferromagnetic layer to flip when the sum of

[0020] The currents input to terminals A and B are:

[0021] For two I S The sum of the two logic inputs A and B is "0" and an I L , an I S The sum of the two logic inputs A and B (one is "1" and the other is "0") can only flip the magnetic moment of a small part of the antiferromagnetic layer and drive the magnetic moment of a small part of the ferromagnetic layer to flip. At this time, the output terminal V AHE The abnormal Hall voltage value V out1 is a small value, and V out1 <V th , the output is judged to be "0".

[0022] The two I L The sum of the two (corresponding to A and B inputs are "1") can make most of the antiferromagnetic layer magnetic moment flip, and drive most of the ferromagnetic layer magnetic moment flip, then the output terminal V AHE The abnormal Hall voltage value V out2 is a large value, and V out2 >V th , recorded as output "1".

[0023] Rule 2: If the initial orientation of the magnetic moment of the magnetic film is along the negative direction of the Z axis, the anomalous Hall voltage output at the output end is V2. When the auxiliary magnetic field H is applied, f Along the X-axis, and |H i |<|H f |time.

[0024] The currents input to terminals A and B are:

[0025] For two I S The sum of the two logic inputs A and B (corresponding to "0" at both logic input terminals A and B) can only flip the magnetic moment of a small part of the antiferromagnetic layer and drive the magnetic moment of a small part of the ferromagnetic layer to flip. At this time, the output terminal V AHE The abnormal Hall voltage value V out1 is a small value, namely V out1 <V th , recorded as output "0".

[0026] And an I L , an I S The sum of the two logic terminals A and B (one is "1" and the other is "0") and the two I LThe sum of the two logic inputs A and B (corresponding to "1") can flip the magnetic moment of most antiferromagnetic layers and drive the magnetic moment of most ferromagnetic layers to flip. At this time, the output terminal V AHE The abnormal Hall voltage value V out2 is a large value, namely V out2 >V th , recorded as output "1".

[0027] Rule 3: If the initial orientation of the magnetic moment of the magnetic film is along the positive direction of the Z axis (the anomalous Hall voltage output at the output end is V1), the applied auxiliary magnetic field H f Along the X-axis, and |H f |<|H i |time.

[0028] The currents input to terminals A and B are:

[0029] For two I S The sum of (corresponding to both A and B inputs being "0") and an I L , an I S The sum of the two (corresponding to A and B, one is "1" and the other is "0") can only flip the magnetic moment of a small part of the antiferromagnetic layer and drive the magnetic moment of a small part of the ferromagnetic layer to flip. At this time, the output terminal V AHE The abnormal Hall voltage value V out1 is a large value, namely V out1 >V th , the output is judged to be "1".

[0030] The two I L The sum of the two (corresponding to A and B inputs are "1") can make most of the antiferromagnetic layer magnetic moment flip, and drive most of the ferromagnetic layer magnetic moment flip, then the output terminal V AHE The abnormal Hall voltage value V out2 is a small value, namely V out2 <V th , recorded as output "0".

[0031] Rule 4: If the initial orientation of the magnetic moment of the magnetic film is along the positive direction of the Z axis (the anomalous Hall voltage output at the output end is V1), when the auxiliary magnetic field H is applied f Along the X-axis, and |H i |<|H f |time.

[0032] The currents input to terminals A and B are:

[0033] For two I S The sum of the two (corresponding to the two input terminals A and B are "0") can only make a small part of the antiferromagnetic layer magnetic moment flip, and drive a small part of the ferromagnetic layer magnetic moment flip, then the output terminal VAHE The abnormal Hall voltage value V out1 is a large value, namely V out1 >V th , recorded as output "1".

[0034] And an I L , an I S The sum of (corresponding to the two inputs A and B, one is "1" and the other is "0") and the two I L The sum of the two (corresponding to both inputs A and B being "1") can flip the magnetic moment of most antiferromagnetic layers and drive the magnetic moment of most ferromagnetic layers to flip. At this time, the abnormal Hall voltage value V obtained at the output end out2 is a small value, namely V out2 <V th , recorded as output "0".

[0035] The above-mentioned control method of the spin logic device based on perpendicular exchange bias can realize AND gate, OR gate, NAND gate, NOR gate, and NOT gate logic based on the ferromagnetic / antiferromagnetic bilayer magnetic film according to rules 1-4. The specific control method is as follows:

[0036] (1) Unit reset (Reset) and set (Set):

[0037] Before implementing the logic functions of the AND gate or OR gate (using gate devices of Rule 1 or Rule 2), the unit needs to be reset so that the initial magnetic moment of the unit is along the negative direction of the Z axis.

[0038] The reset operation steps are as follows: Apply a magnitude corresponding to the rule in the X-axis direction. f |Size is consistent, direction is consistent with the corresponding rules H f An opposite magnetic field (the positive or negative of the magnetic field is determined by the selected injection polarization flow layer material. When the spin Hall angle of the selected heavy metal material is positive, such as Pt, it is positive; when the spin Hall angle of the selected heavy metal material is negative, such as Ta, W, it is negative) is applied along the positive direction of the X axis at the same time. L The pulse current is large or small. At this time, no matter what the magnetic moment orientation of the ferromagnetic / antiferromagnetic bilayer film is before, the spin-orbit moment will make the magnetic moment oriented along the negative direction of the Z axis. The anomalous Hall voltage value obtained at the output end is a small value, which is recorded as the output "0". At this time, the reset operation is completed.

[0039] Before realizing the logic functions of NAND gate, NOR gate, and NOT gate (gate devices using rule 3 or rule 4), the unit needs to be set (Set) so that the initial magnetic moment of the unit is along the positive direction of the Z axis.

[0040] The steps of setting are as follows: Apply a size corresponding to the rule |H along the X-axis direction f|Size is consistent, direction is consistent with the corresponding rules H f An opposite magnetic field (the positive or negative of the magnetic field is determined by the selected injection polarization flow layer material. When the spin Hall angle of the selected heavy metal material is positive, such as Pt, it is negative; when the spin Hall angle of the selected heavy metal material is negative, such as Ta, W, etc., it is positive) is applied along the positive direction of the X axis at the same time. L The pulse current is large or small. At this time, no matter what the magnetic moment orientation of the ferromagnetic / antiferromagnetic bilayer film is, the spin-orbit moment will make the magnetic moment oriented along the positive direction of the Z axis. The anomalous Hall voltage value obtained at the output end is a large value, which is recorded as the output "1". At this time, the set operation is completed.

[0041] (2) Implementation of AND gate:

[0042] After resetting the unit, inject the corresponding current into the input terminals A and B as shown in Table 1, and apply an auxiliary magnetic field H along the X-axis. f , and |H f |<|H i |, at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 1, the output end can obtain the AND gate logic rule shown in Table 1 below.

[0043] Table 1 AND gate logic rule truth table

[0044]

[0045] (3) Implementation of OR gate:

[0046] After resetting the unit, inject the corresponding current into the input terminals A and B as shown in Table 2, and apply an auxiliary magnetic field H along the X-axis. f , and |H i |<|H f |, at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 2, the output end can obtain the OR gate logic rule shown in Table 2 below.

[0047] Table 2 OR gate logic rule truth table

[0048]

[0049] (4) Implementation of NAND gate:

[0050] First, after performing the Set operation on the unit, the corresponding current is injected into the input terminals A and B as shown in Table 3, and an auxiliary magnetic field H is applied along the X-axis direction. f , and |H f |<|H i|, at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 3, the output end can obtain the NAND gate logic rule shown in Table 3 below.

[0051] Table 3. Truth table of logic rules of NAND gate

[0052]

[0053] (5) Implementation of NOR gate:

[0054] First, after the Set operation is performed on the unit, the corresponding current is injected into the input terminals A and B as shown in Table 4 below, and an auxiliary magnetic field H is applied along the X-axis direction. f , and |H i |<|H f |, at this time, the ferromagnetic / antiferromagnetic bilayer film is driven to flip rule 4 according to the spin-orbit moment, and the output end can obtain the NOR gate logic rule shown in Table 4 below.

[0055] Table 4. NOR gate logic rule truth table

[0056]

[0057] (6) Implementation of NOT gate:

[0058] First, after performing the Set operation on the unit, the corresponding current is injected into the input terminals A and B as shown in Table 5, and an auxiliary magnetic field H is applied along the X-axis direction. f , and |H f |<|H i Since the NOT gate only needs one input, the fixed input terminal A is always "1". At this time, the spin-orbit moment drives the ferromagnetic / antiferromagnetic bilayer to flip rule 3, and the output terminal can obtain the NOT gate logic rules shown in Table 5 below.

[0059] Table 5 NOT gate logic rule truth table

[0060]

[0061] This invention proposes fabricating a spin logic device using a ferromagnetic / antiferromagnetic bilayer perpendicular exchange bias structure. This method utilizes the spin-orbit moment to drive the magnetic moment reversal at the interface between the ferromagnetic and antiferromagnetic layers, thereby changing the magnitude and direction of the exchange bias field within the ferromagnetic / antiferromagnetic bilayer perpendicular exchange bias system and ultimately driving the magnetic moment reversal of the ferromagnetic layer. Because antiferromagnetic materials are inherently resistant to large magnetic field interference, this method not only enables the realization of novel spin logic devices based on antiferromagnetic materials, but also improves their anti-interference capabilities and achieves lower drive current density.

[0062] In summary, the present invention changes the magnetic moment orientation of the ferromagnetic layer and the antiferromagnetic layer, thereby realizing a magnetic logic device. The magnetic logic device realized by this method has the advantages of stronger resistance to external magnetic field interference, low switching current density, simple structure, and compatibility with MRAM process. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 Schematic diagram of the device structure of the present invention;

[0064] Figure 2 Schematic diagram of output logic changes implemented by an AND gate in an embodiment;

[0065] Figure 3 This is a schematic diagram of output logic changes implemented by an OR gate in an embodiment;

[0066] Figure 4 2. It is a schematic diagram of output logic changes implemented by a NAND gate in an embodiment;

[0067] Figure 5 Schematic diagram of output logic changes implemented by a NOR gate in an embodiment;

[0068] Figure 6 2. It is a schematic diagram of output logic changes implemented by a NOT gate in an embodiment;

[0069] Reference numerals: 1 - injection polarization flow layer, 2 - ferromagnetic layer, 3 - antiferromagnetic layer, 4 - protective layer. DETAILED DESCRIPTION

[0070] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0071] A spin logic device based on vertical exchange bias is fabricated on a substrate using photolithography and thin film technology. The spin logic unit has a structure of injection polarization layer / ferromagnetic layer / antiferromagnetic layer / cover layer, and includes the following fabrication steps:

[0072] Step 1: Select a conventional Si / SiO2 substrate as the device substrate and photolithography it into Figure 1The electrode portion shown in the figure shows a cross-shaped structure, which is an injection polarization layer used to provide spin-orbit current to drive the ferromagnetic / antiferromagnetic magnetic moment reversal. The material is heavy metal Pt, with a thickness of 6nm. The Y-axis electrode is used to test the anomalous Hall voltage. Step 2: Based on Step 1, reverse photolithography is performed to create the magnetoresistive pattern, and a thin film is deposited on the substrate using a thin film deposition process. The structure is Co (0.8nm) / IrMn (5nm) / Ta (1.5nm). The ferromagnetic layer Co (0.8nm) is induced to have perpendicular anisotropy by the heavy metal layer, which also induces perpendicular anisotropy in the antiferromagnetic layer. The antiferromagnetic layer IrMn (5nm) induces perpendicular anisotropy at the interface with the ferromagnetic layer, generating a perpendicular exchange bias with the ferromagnetic layer. This exchange bias serves as a medium for storing information. The cap layer Ta (1.5nm) protects the device.

[0073] After the spin logic device is fabricated, in order to control the magnetic moment of the device, it is necessary to inject a current pulse into the device's injection polarization layer along the positive direction of the X axis. In this embodiment, two current pulses I A and I B As the two inputs of the gate device, they are regarded as input A and input B respectively, such as Figure 1 When constructing the corresponding gate logic device, it is necessary to apply the corresponding auxiliary magnetic field H on the X axis. f , to meet the requirements of spin-orbit torque driving the vertical magnetic moment reversal of ferromagnetic and antiferromagnetic materials.

[0074] According to the above rules 1-4, the AND gate, OR gate, NAND gate, NOR gate, and NOT gate logic are realized based on the ferromagnetic / antiferromagnetic double-layer magnetic film. The specific implementation method is as follows:

[0075] (1) Implementation of AND gate:

[0076] According to Rule 1, since the spin Hall angle of Pt is positive, we can determine H f -600 Oe (ie, the magnetic field direction is along the negative direction of the X axis); I L The magnitude is 12mA, and the direction is the positive direction of the X axis; I S The magnitude is 8mA and the direction is the positive direction of the X axis.

[0077] Before realizing the logic relationship of the AND gate, the unit needs to be reset: apply a 600 Oe magnetic field along the positive direction of the X axis, and at the same time apply a 24mA pulse current along the positive direction of the X axis. At this time, no matter what the magnetic moment orientation of the ferromagnetic / antiferromagnetic bilayer film is before, the spin-orbit moment will make the magnetic moment oriented along the negative direction of the Z axis, thus completing the reset operation. Figure 2 As shown in the table below, after the unit is reset, the corresponding current is injected into the input terminals A and B, and an auxiliary magnetic field H is applied along the X-axis direction.f (-600 Oe), at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer film flip rule 1, the output end can obtain the AND gate logic rule shown in the following table.

[0078] Table 1 AND gate logic rule truth table

[0079]

[0080] (2) Implementation of OR gate:

[0081] According to Rule 2, determine H f -3000 Oe (ie, the magnetic field direction is along the negative direction of the X axis); I L The magnitude is 12mA, and the direction is the positive direction of the X axis; I S The magnitude is 8mA and the direction is the positive direction of the X axis.

[0082] Before realizing the OR gate logic relationship, the unit needs to be reset: apply a 3000 Oe magnetic field along the positive direction of the X axis, and at the same time apply a 24mA pulse current along the positive direction of the X axis. At this time, no matter what the magnetic moment orientation of the ferromagnetic / antiferromagnetic bilayer film is before, the spin-orbit moment will make the magnetic moment oriented along the negative direction of the Z axis, thus completing the reset operation. Figure 3 As shown in the table below, after the unit is reset, the corresponding current is injected into the input terminals A and B, and an auxiliary magnetic field H is applied along the X-axis direction. f (-3000 Oe), at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 2, the output end can obtain the OR gate logic rule shown in the following table.

[0083] Table 2 OR gate logic rule truth table

[0084]

[0085] (3) Implementation of NAND gate:

[0086] According to Rule 3, determine H f is 600 Oe (i.e. the magnetic field direction is along the positive direction of the X axis); I L The magnitude is 12mA, and the direction is the positive direction of the X axis; I S The magnitude is 8mA and the direction is the positive direction of the X axis.

[0087] Before realizing the logical relationship of the NAND gate, the unit needs to be set: a 600 Oe magnetic field is applied along the negative direction of the X axis, and a 24mA pulse current is applied along the positive direction of the X axis. At this time, no matter what the magnetic moment orientation of the ferromagnetic / antiferromagnetic bilayer film is, the spin-orbit moment will make the magnetic moment oriented along the positive direction of the Z axis, thus completing the set operation. Figure 4As shown, after the unit is set to Set, the corresponding current is injected into the input terminals A and B as shown in the following table, and an auxiliary magnetic field H is applied along the X-axis direction. f (600 Oe), at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 3, the output end can obtain the NAND gate logic rule shown in the following table.

[0088] Table 3. Truth table of logic rules of NAND gate

[0089]

[0090] (4) Implementation of NOR gate:

[0091] According to Rule 4, determine H f is 3000 Oe (i.e. the magnetic field direction is along the positive direction of the X axis); I L The magnitude is 12mA, and the direction is the positive direction of the X axis; I S The magnitude is 8mA and the direction is the positive direction of the X axis.

[0092] Before realizing the logical relationship of the NOR gate, the unit needs to be set: a 3000 Oe magnetic field is applied along the negative direction of the X axis, and a 24mA pulse current is applied along the positive direction of the X axis. At this time, no matter what the magnetic moment orientation of the ferromagnetic / antiferromagnetic bilayer film is, the spin-orbit moment will make the magnetic moment oriented along the positive direction of the Z axis, thus completing the set operation. Figure 5 As shown, after the unit is set to Set, the corresponding current is injected into the input terminals A and B as shown in the following table, and an auxiliary magnetic field H is applied along the X-axis direction. f (3000 Oe), at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 4, the output end can obtain the NOR gate logic rule shown in the following table.

[0093] Table 4. NOR gate logic rule truth table

[0094]

[0095] (5) Implementation of NOT gate:

[0096] According to Rule 3, determine H f is 600 Oe (i.e. the magnetic field direction is along the positive direction of the X axis); I L The magnitude is 12mA, and the direction is the positive direction of the X axis; I S The magnitude is 8mA and the direction is the positive direction of the X axis.

[0097] Before realizing the logic relationship of the NOT gate, the unit needs to be set: a 600 Oe magnetic field is applied along the negative direction of the X axis, and a 24mA pulse current is applied along the positive direction of the X axis. At this time, no matter what the magnetic moment orientation of the ferromagnetic / antiferromagnetic bilayer film is, the spin-orbit moment will make the magnetic moment oriented along the positive direction of the Z axis, and the set operation is completed. Figure 6 As shown, after the unit is set to Set, the corresponding current is injected into the input terminals A and B as shown in the following table, and an auxiliary magnetic field H is applied along the X-axis direction. f (600 Oe). Since the NOT gate only needs one input, the fixed input terminal A is always "1". At this time, the ferromagnetic / antiferromagnetic bilayer is driven by the spin-orbit moment to flip rule 3, and the output terminal can obtain the NOT gate logic rules shown in the following table.

[0098] Table 5 NOT gate logic rule truth table

[0099]

[0100] As can be seen from the above examples, the present invention utilizes a ferromagnetic / antiferromagnetic bilayer perpendicular exchange bias structure to fabricate a spin logic device. By utilizing the spin-orbit moment effect, an input current generates a spin-polarized current in the heavy metal layer, thereby modulating the exchange bias field in the ferromagnetic / antiferromagnetic bilayer. By measuring the anomalous Hall voltage in the structure and adjusting the magnitude of the spin-orbit moment injection current along the long axis of the cell, AND, NAND, OR, NOR, and NOT logic gates are implemented. This invention not only realizes a novel spin logic device based on antiferromagnetic materials, but also has advantages such as stronger resistance to external magnetic field interference, low switching current density, simple structure, and compatibility with MRAM processes.

Claims

1. A spin logic device based on vertical exchange bias, characterized in that: The structure from bottom to top is: injection polarization layer / ferromagnetic layer / antiferromagnetic layer / cover layer. The spin logic unit is a double-layer magnetic film of ferromagnetic layer / antiferromagnetic layer, and the magnetic moment of the magnetic film is oriented along the out-of-plane direction. The injection polarization flow layer is a cross-shaped thin film made of a heavy metal material with spin-orbit coupling, and its thickness is less than the spin diffusion length of the injection polarization flow layer material; The center point of the cross-shaped injection polarization flow layer is used as the origin of the coordinate system, the direction perpendicular to the film surface is the positive direction of the Z axis, and the two mutually perpendicular sides of the cross are used as the X axis and Y axis respectively. Two current pulse input terminals A and B are provided in the negative direction of the X axis, and an output terminal is provided in the positive direction of the X axis. The current flows from the negative direction of the X axis to the positive direction of the X axis. Positive and negative test points for the abnormal Hall voltage are provided in the positive / negative directions of the Y axis of the injection polarization flow layer. The magnetic film is arranged on the X-axis in such a way that its physical center overlaps with the origin of the injection polarization flow layer, and the major axis direction of the magnetic film is the X-axis direction, and the minor axis direction is the Y-axis direction; the width of the magnetic film is consistent with the width of the injection polarization flow layer on the X-axis, and the width of the injection polarization flow layer on the Y-axis is ≤ its length ≤ the length of the injection polarization flow layer on the X-axis; The covering layer is arranged on the magnetic film in a completely covering manner.

2. The spin logic device based on vertical exchange bias according to claim 1, wherein: The material of the injection polarization flow layer is Ta, W and / or Pt.

3. The spin logic device based on vertical exchange bias according to claim 1, wherein: The ferromagnetic layer material is selected from CoFeB, CoFe and / or Co.

4. The spin logic device based on vertical exchange bias according to claim 1, wherein: The antiferromagnetic material is selected from IrMn, FeMn and / or PtMn.

5. The spin logic device based on vertical exchange bias according to claim 1, wherein: The cover layer material is Ta or Cu.

6. The spin logic device based on vertical exchange bias according to claim 1, wherein: The methods for controlling the magnetic moment are: In the injection polarization flow layer, a current pulse is injected along the positive direction of the X axis. Two current pulses I A and I B As the two inputs of the gate device, they correspond to input terminal A and input terminal B respectively; when realizing the corresponding gate logic device, the corresponding auxiliary magnetic field H is applied on the X axis. f ; Among them H f A positive value indicates that the magnetic field is along the positive direction of the X axis, H f Negative indicates that the magnetic field is in the negative direction of the X axis, H f The positive or negative value of is determined by the selected injection polarization flow layer material; when the selected heavy metal material spin Hall angle is positive, the selected H f <0; when the spin Hall angle of the selected heavy metal material is negative, the selected H f >0; to meet the requirement of spin-orbit moment driving the vertical magnetic moment reversal of ferromagnetic and antiferromagnetic materials; The two input logic states 1 and 0 of the gate circuit correspond to the input of a large current pulse I L and a small current pulse I S , I L >I S ;I L and I S Size and H f The direction and magnitude of the spin-orbit moment drive the magnetization reversal of the ferromagnetic layer / antiferromagnetic layer, V th is the set judgment voltage; Rule 1: If the initial orientation of the magnetic moment of the magnetic film is along the negative direction of the Z axis, the anomalous Hall voltage output at the output end is V2, and the applied auxiliary magnetic field H f Along the X-axis, and |H f |<|H i |, where H i The applied current is I L +I S The magnetic field required for half of the magnetic moments of the ferromagnetic layer and the antiferromagnetic layer to flip when the sum of The currents input to terminals A and B are: Two I's S The sum corresponds to both logic inputs A and B being 0, and an I L , an I S The sum corresponds to the two logic inputs A and B, one is 1 and the other is 0; at this time, the output terminal V AHE The abnormal Hall voltage value V out1 is a small value, and V out1 <V th , the output is judged to be 0; The two I L The sum of the two inputs A and B corresponds to 1, and the output terminal V AHE The abnormal Hall voltage value V out2 is a large value, and V out2 >V th , recorded as output 1; Rule 2: If the initial orientation of the magnetic moment of the magnetic film is along the negative direction of the Z axis, the anomalous Hall voltage output at the output end is V2. When the auxiliary magnetic field H is applied, f Along the X-axis, and |H i |<|H f | time; The currents input to terminals A and B are: Two I's S The sum of the two logic input terminals A and B is 0, and the output terminal V AHE The abnormal Hall voltage value V out1 is a small value, namely V out1 <V th , recorded as output 0; And an I L , an I S The sum corresponds to the two logic inputs A and B, one is 1 and the other is 0, and the two I L The sum of the two logic inputs A and B corresponds to 1, and the output terminal V AHE The abnormal Hall voltage value V out2 is a large value, namely V out2 >V th , recorded as output 1; Rule 3: If the initial orientation of the magnetic moment of the magnetic film is along the positive direction of the Z axis, the anomalous Hall voltage output at the output end is V1, and the applied auxiliary magnetic field H f Along the X-axis, and |H f |<|H i | time; The currents input to terminals A and B are: Two I's S The sum corresponds to both inputs A and B being 0, and an I L , an I S The sum of the two inputs A and B corresponds to one being 1 and the other being 0. At this time, the output terminal V AHE The abnormal Hall voltage value V out1 is a large value, namely V out1 >V th , the output is judged to be 1; The two I L The sum of the two inputs A and B corresponds to 1, and the output terminal V AHE The abnormal Hall voltage value V out2 is a small value, namely V out2 <V th , recorded as output 0; Rule 4: If the initial orientation of the magnetic moment of the magnetic film is along the positive direction of the Z axis, the anomalous Hall voltage output at the output end is V1. When the auxiliary magnetic field H is applied, f Along the X-axis, and |H i |<|H f | time; The currents input to terminals A and B are: Two I's S The sum of the two input terminals A and B is 0, and the output terminal V AHE The abnormal Hall voltage value V out1 is a large value, namely V out1 >V th , recorded as output 1; An I L , an I S The sum corresponds to two inputs A and B, one is 1 and the other is 0, and two I L The sum corresponds to both inputs A and B being 1, and the abnormal Hall voltage value V obtained at the output end is out2 is a small value, namely V out2 <V th , recorded as output 0; According to rules 1-4, AND gate, OR gate, NAND gate, NOR gate and NOT gate logic can be realized based on the ferromagnetic / antiferromagnetic double-layer magnetic film.

7. The spin logic device based on vertical exchange bias according to claim 6, characterized in that: The specific logic control methods of AND gate, OR gate, NAND gate, NOR gate and NOT gate are as follows: (1) Unit reset Reset and set Set: Before using Rule 1 or Rule 2 to implement AND gate or OR gate logic functions, the unit must be reset to make the initial magnetic moment of the unit along the negative direction of the Z axis. The reset operation steps are as follows: Apply a magnitude corresponding to the rule in the X-axis direction. f |Size is consistent, direction is consistent with the corresponding rules H f The opposite magnetic field is applied along the positive direction of the X axis with a value of 2 times I L The pulse current of different sizes, at this time, no matter what the magnetic moment orientation of the ferromagnetic / antiferromagnetic bilayer film is before, the spin-orbit moment will make the magnetic moment oriented along the negative direction of the Z axis, and the anomalous Hall voltage value obtained at the output end is a small value, which is recorded as the output 0, and the reset operation is completed at this time; Before using rule 3 or rule 4 to implement the logic functions of NAND gate, NOR gate, and NOT gate, the unit must be set to the positive direction of the Z axis. The steps of setting are as follows: Apply a size corresponding to the rule |H along the X-axis direction f |Size is consistent, direction is consistent with the corresponding rules H f The opposite magnetic field is applied along the positive direction of the X axis with a value of 2 times I L The pulse current of different sizes, at this time, no matter what the magnetic moment orientation of the ferromagnetic / antiferromagnetic bilayer film is before, the spin-orbit moment will make the magnetic moment oriented along the positive direction of the Z axis, and the anomalous Hall voltage value obtained at the output end is a large value, which is recorded as output 1, and the set operation is completed at this time; (2) Implementation of AND gate: After resetting the unit, inject the corresponding current into the input terminals A and B as shown in Table 1, and apply an auxiliary magnetic field H along the X-axis. f , and |H f |<|H i |, at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 1, the output end can obtain the AND gate logic rule shown in Table 1 below; Table 1 AND gate logic rule truth table (3) Implementation of OR gate: After resetting the unit, inject the corresponding current into the input terminals A and B as shown in Table 2, and apply an auxiliary magnetic field H along the X-axis. f , and |H i |<|H f |, at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 2, the output end can obtain the OR gate logic rule shown in Table 2 below; Table 2 OR gate logic rule truth table (4) Implementation of NAND gate: First, after performing the Set operation on the unit, the corresponding current is injected into the input terminals A and B as shown in Table 3, and an auxiliary magnetic field H is applied along the X-axis direction. f , and |H f |<|H i |, at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 3, the output end can obtain the NAND gate logic rule shown in Table 3 below; Table 3. Truth table of logic rules of NAND gate (5) Implementation of NOR gate: First, after performing the Set operation on the unit, the corresponding current is injected into the input terminals A and B as shown in Table 4, and an auxiliary magnetic field H is applied along the X-axis direction. f , and |H i |<|H f |, at this time, according to the spin-orbit moment driving the ferromagnetic / antiferromagnetic bilayer flip rule 4, the output end can obtain the NOR gate logic rule shown in Table 4 below; Table 4. NOR gate logic rule truth table (6) Implementation of NOT gate: First, after performing the Set operation on the unit, the corresponding current is injected into the input terminals A and B as shown in Table 5, and an auxiliary magnetic field H is applied along the X-axis direction. f , and |H f |<|H i Since the NOT gate only needs one input, the fixed input terminal A is always 1. At this time, according to the spin-orbit moment, the ferromagnetic / antiferromagnetic bilayer flip rule 3 is driven, and the output terminal can obtain the NOT gate logic rules shown in Table 5 below; Table 5 NOT gate logic rule truth table 。

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