CN108010549B

CN108010549B - Self-rotating polarized current generator and magnetic device thereof

Info

Publication number: CN108010549B
Application number: CN201711261286.9A
Authority: CN
Inventors: 夏钶; 闵泰; 郝润姿; 赵京延; 王蕾
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2017-12-04
Filing date: 2017-12-04
Publication date: 2021-03-16
Anticipated expiration: 2037-12-04
Also published as: CN108010549A

Abstract

The invention discloses a spin-polarized current generator and a magnetic device thereof. The generator uses an antiferromagnetic material and a metal material to form an asymmetric laminated structure for generating spin-polarized current, has low resistivity, and thus can reduce power consumption. The magnetic device includes a first conductive layer, and at least one stacked structure of an antiferromagnetic layer and a second conductive layer on the first conductive layer, the antiferromagnetic layer being adjacent to the first conductive layer; a magnetic junction is disposed on the first conductive layer adjacent to the stacked structure, the magnetic junction including a free magnetic layer. The device can reduce the heating of the device and improve the reliability and stability of the device.

Description

Self-rotating polarized current generator and magnetic device thereof

Technical Field

The present invention relates to circuits and devices having magnetic/antiferromagnetic materials or structures and applications thereof, and more particularly to spin-polarized current generators and magnetic devices thereof.

Background

Spin is one of the inherent properties of particles such as electrons. The electrons have two different spin states (generally defined as spin-up and spin-down). The electrons in the current may be non-spin polarized, with equal probability for electrons of different spin states, or spin polarized, with a greater number of electrons in one spin state than in the other, such a current being referred to as a spin polarized current. A conventional spin-polarized current can be realized, for example, by passing a current through a (first) magnetic layer having a specific magnetization orientation, which can then be directed into another (second) magnetic layer, causing a transfer of angular momentum, whereby an excited spin-transfer torque (called STT) has an effect on the local magnetic moment in the second magnetic layer, resulting in a precession of the magnetization of the second magnetic layer, or a switching of the magnetization (switching of the magnetization orientation).

A Magnetic Tunnel Junction (MTJ) consists of two layers of magnetic metal (e.g., iron, cobalt, nickel) and an ultra-thin insulating layer (e.g., aluminum oxide, or magnesium oxide) sandwiched between the two magnetic metal layers. If a bias voltage is applied between two magnetic metal layers, electrons can tunnel through their potential barrier due to the thin insulating layer. The magnitude of the tunneling current/resistance at a given bias depends on the relative orientation of the magnetization in the two ferromagnetic layers, a phenomenon known as Tunneling Magnetoresistance (TMR), which is a manifestation of the spin-dependent tunneling effect. The relative orientation of the magnetizations in the two ferromagnetic layers can be changed by an applied magnetic field.

A spin valve is a device composed of two or more electrically conductive magnetic materials whose resistance can be varied between two values (high and low) depending on the relative orientation of the magnetization in the different layers. The resistance change is the result of the giant magnetoresistive (so-called GMR) effect. In the simplest case, a spin valve consists of two ferromagnets and a non-magnetic material sandwiched between the two ferromagnets, one of which (referred to as the first ferromagnet) is fixed by an antiferromagnet and serves to increase the magnetic coercivity of the first ferromagnet so that it behaves as a "hard" magnetic layer, while the other (referred to as the second ferromagnet) has its magnetization orientation changeable, behaving as a "soft" magnetic layer. The nonmagnetic layer separates the two ferromagnetic layers so that one of them retains the magnetization orientation free (soft magnetic). Due to the difference in coercivity, the soft layer can change polarity at lower applied magnetic field strengths, while the hard layer magnetization remains unchanged. Thus, by applying an externally applied magnetic field of appropriate strength, the soft magnetic layer can be switched in polarity so that the spin valve has two different states: a low resistance state where the two magnetic layers magnetize in parallel and a high resistance state where the two magnetic layers magnetize antiparallel.

Nowadays, magnetic junctions (called MJ, including MTJ and spin valve) are commonly used in magnetic random access memories. Magnetic random access memories are of increasing interest to researchers due to their advantages of non-volatility, excellent endurance, high read/write speed, low power consumption, etc. A magnetoresistive element in a Magnetic Random Access Memory (MRAM), referred to as MRAM, may be a magnetic junction including two or more ferromagnetic thin films. The resistance of MJ depends on the relative orientations of the magnetizations of the fixed and free magnetic layers, the magnetic moment of the free magnetic layer (referred to as FL) can be switched between two stable orientations, and the resistance of MJ assumes two values with the two relative magnetic orientations of the fixed and free magnetic layers, which can be used to represent binary states "1" and "0" for data storage and applies to binary logic. The orientation of the free layer magnetization of the magnetic junction can be changed by an applied magnetic field to obtain a low resistance state ("1") or a high resistance state ("0") corresponding to the free magnetic layer being parallel or anti-parallel to the fixed magnetic layer magnetization, and thus the 1/0 state required by the logic circuit. However, the application of current to provide an applied magnetic field requires a large current density, consumes a large amount of power, and limits the density of the memory cell array, i.e., the magnetic junction array.

One type of MRAM is spin transfer torque-random access memory (STT-RAM). The magnetization direction of the free magnetic layer is switched by changing the current direction by utilizing the effect of the spin-polarized current on the magnetic moment (spin torque), thereby completing data writing of MJ in the STT-RAM. Data writing to the STT-RAM can also be accomplished by a combination of spin-polarized current and other effects (e.g., changing the magnetocrystalline anisotropy of the free magnetic layer, electric fields, thermal effects, deformation, etc.).

The MRAM bit cell has a two-terminal structure and a three-terminal structure, the read-write paths of the two-terminal structure are the same, and the reliability of the MTJ MRAM with the two-terminal structure has a greater challenge because the insulating tunnel barrier layer may be broken down when a current passes through the insulating tunnel barrier layer. The three-terminal structure separates the read-write path, so that the read-write path and the read-read path can be respectively matched with an external circuit in impedance, the performance of the structure is improved, and the problem of breakdown of a barrier layer of an insulating tunnel during current storage and writing is solved. The typical application of the three-terminal structure is a SHE MRAM (spin Hall effect magnetic random access memory), in which a heavy metal layer is added on one side of a free layer of an MRAM magnetic junction, and when current flows in the heavy metal layer, spin polarization is generated in a direction perpendicular to a current flow direction due to a spin Hall effect, so that spin-polarized current is obtained to drive magnetization reversal of an adjacent free layer. Theta for spin conversion efficiency of SHE MRAM_SH(spin Hall angle) represents, θ_SHDefined as the ratio of the transverse spin conductivity to the longitudinal conductivity, or the ratio of the transverse spin current density to the applied longitudinal current density, in a patent of "Circuits and devices based on spin hall effect to application a spin transfer torque with a component dependent on the plane of magnetic layers" (U.S. Pat. No. US 9,691,458B2) at Cornell university, SHE materials are heavy metals with high atomic number, such as Ta, W, Hf or Pt, or alloys and intermetallic compounds thereof, which, in a certain atomic structure, have a spin hall angle of greater than or equal to 8%, such as theta_SH(β -Ta) ═ 15%. The disadvantage of SHE MRAM is that the heavy metal layer of the core structure has a large resistivity, e.g., at room temperature, the resistivity of beta-Ta is rho_NM(β -Ta) ═ 200(μ Ω · cm), and the spin conversion efficiency (spin hall angle) is | θ_SH(beta-Ta) | 2-15%, and the resistivity of beta-W is rho_NM(beta-W) 227 to 312 (mu omega cm), and the spin conversion efficiency (spin Hall angle) is | theta_SH(beta-W) | 33 +/-6%), and the resistivity of Pt is rho_NM(Pt) 15.6-98.0 (mu omega cm) and a spin Hall angle of theta_SH(Pt) | 0.6% -16%, since suitable and highly efficient heavy metal materials generally have very high resistivity, when current passes through the heavy metal layer, according to joule's law (Q ═ I)²Rt), which generates a large amount of joule heat, resulting in a large energy consumption in writing data, and the generated heat increases the operating temperature of the device, which seriously affects the stability of the memory device, and the resistivity of the device increases with the temperature increase, and a fixed operating voltage (operating voltage V provided by each semiconductor technology node) is provided for industrial use_ddLimited and declining), the write current will be continuously reduced, and thus may beThe problems of insufficient write current to make the magnetization of the free magnetic layer flip and write failure can be caused, and the reliability of the device is reduced, so that the overlarge resistivity may become a primary factor influencing the wide application of the SHE MRAM.

Disclosure of Invention

To solve the above-mentioned problems in the prior art, it is an object of the present invention to provide a spin-polarized current generator, which uses an antiferromagnetic material and a metal material to form an asymmetric lamination structure for generating a spin-polarized current, has a low resistivity, and thus can reduce power consumption.

It is a further object of the present invention to provide a magnetic device based on such a spin polarized current generator that reduces device heating and improves device reliability and stability of operation.

The invention is realized by the following technical scheme:

the invention provides a spin polarized current generator, comprising:

a first conductive layer, a second conductive layer, and an antiferromagnetic layer between the first conductive layer and the second conductive layer

The first conductive layer, the second conductive layer, and the antiferromagnetic layer constitute a first conductive layer-antiferromagnetic layer-second conductive layer laminated structure through which a current can be passed to generate spin polarization.

Preferably, the antiferromagnetic layer of the laminated structure is a single layer material or a composite layer composed of a plurality of materials, and the single layer material includes a metal, an alloy, or a rare earth metal and an alloy thereof; the composite layer is made of synthetic antiferromagnetic material, and the composite layer made of the synthetic antiferromagnetic material is composed of a ferromagnetic layer and a spacer layer.

Further, the metal or alloy constituting the single layer material includes Cr, CoRh, ferah, Cr-based alloy: CrV, CrMn, CrRe, CrFe, CrRu, CrOs, CrCo, CrRh, CrIr, CrNi, CrPd, CrPt, CrCu, CrAg, CrAu, CrGa, CrIn, CrMnPt, FeNiCr, Mn-based alloy: CrMn, ReMn, FeMn, RuMn, OsMn, CoMn, RhMn, IrMn, NiMn, PdMn, PtMn, CuMn, AgMn, AuMn, PdPtMn, CoCrMn, and NiFeCrCo-based alloys.

Further, the rare earth metal and the alloy thereof which form the single-layer material comprise one or more of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu;

the rare earth metal alloy includes rare earth metals and conventional metals selected from one or more of, but not limited to, Y, Fe, Ni, Pd, Al, In, Gd, Sn.

Preferably, the ferromagnetic layer material constituting the composite layer is selected from, but not limited to, Fe, Co, CoFe, Ni, CoCrPt, CoFeB, (Co/Ni)_p、(Co/Pd)_m、(Co/Pt)_nWhere m, n, p refer to the number of repetitions of the multilayer stack.

Preferably, the spacer layer material constituting the composite layer is selected from one or more of Nb, Ta, Cr, Mo, W, Re, Ru, Os, Rh, Ir, Pt, Cu, Ag, Au, but not limited thereto.

Preferably, the first conductive layer and the second conductive layer are respectively selected from the following different metal or alloy materials:

one or more of Li, Mg, Al, Ca, Sc, Ti, V, Mn, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Po, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb.

Preferably, the thickness of the antiferromagnetic layer is 0.1 nm-10 nm; the thickness of the first conducting layer is 1 nm-100 nm; the thickness of the second conductive layer is 1 nm-100 nm.

Further, the thickness of the first conductive layer and the thickness of the second conductive layer may be the same or different.

The invention further provides a magnetic device formed by using the spin-polarized current generator, which comprises a first conducting layer and at least one stacked structure formed by an antiferromagnetic layer and a second conducting layer, wherein the antiferromagnetic layer is adjacent to the first conducting layer; a magnetic junction is arranged on the first conductive layer adjacent to the stacked structure, and the magnetic junction comprises a free magnetic layer;

when current passes through at least one of the stacked structures to the first conductive layer structure, the spin-polarized current generated exerts a spin torque on the free magnetic layer; when no current flows, spin polarization current is not generated;

the magnetic moment of the free magnetic layer is switched using at least a spin torque applied by a spin-polarized current generated by a current passing through at least one of the stack structures to the first conductive layer structure.

Preferably, the first conductive layer is shared by one or more stacked structures and the first conductive layer is shared by one or more of the magnetic junctions.

Preferably, the second conductive layer of the at least one stacked structure is made of different conductive materials to generate spin currents having different polarizations;

the antiferromagnetic layers of the at least one stacked structure have different thicknesses to generate spin currents having different polarizations.

Preferably, the free magnetic layer is made of a ferromagnetic or ferrimagnetic metal and alloys thereof selected from, but not limited to, Fe, Co, Ni, Mn, NiFe, FePd, FePt, CoFe, CoPd, CoPt, YCo, LaCo, PrCo, NdCo, SmCo, CoFeB, BiMn, NiMnSb, and combinations thereof with one or more metals of B, Al, Zr, Hf, Nb, Ta, Cr, Mo, Pd, Pt.

Preferably, the free magnetic layer is made of a synthetic ferromagnetic or ferrimagnetic material selected from, but not limited to, 3d/4d/4f/5d/5 f/rare earth metal layer stacked artificial multilayer structure Co/Ir, Co/Pt, Co/Pd, CoCr/Pt, Co/Au, Ni/Co.

Preferably, the free magnetic layer is made of a half-metallic ferromagnetic material comprising a form of XYZ or X₂The Heusler alloy of YZ, wherein X is selected from but not limited to one or more of Mn, Fe, Co, Ni, Pd, Cu, Y is selected from but not limited to one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Z is selected from but not limited to Al, Cu, Ni, Cu, Fe, Ni, Ti, Ni, Ti, Ni,Ga. One or more of In, Si, Ge, Sn, Sb.

Preferably, the free magnetic layer is made of Synthetic Antiferromagnetic (SAF) material, and the free magnetic layer made of the SAF material is composed of a ferromagnetic layer and a spacer layer; the ferromagnetic layer material comprising the free magnetic layer is selected from, but not limited to, Fe, Co, CoFe, Ni, CoCrPt, CoFeB, (Co/Ni)_p、(Co/Pd)_m、(Co/Pt)_nWherein m, n, p refer to the number of repetitions of the multilayer stack;

the spacer layer material constituting the free magnetic layer is selected from one or more of Nb, Ta, Cr, Mo, W, Re, Ru, Os, Rh, Ir, Pt, Cu, Ag, Au, but not limited thereto.

Preferably, the magnetic moment of the free magnetic layer is perpendicular to the plane of the free magnetic layer; or the magnetic moment of the free magnetic layer is in the plane of the free magnetic layer.

Preferably, the magnetic junction further comprises a fixed magnetic layer, and a nonmagnetic spacer layer between the free magnetic layer and the fixed magnetic layer, the free magnetic layer being for data storage.

Preferably, the nonmagnetic spacer layer is an oxide, nitride or oxynitride, and the constituent elements of the oxide, nitride or oxynitride material are selected from one or more of, but not limited to, Mg, B, Al, Ca, Sr, La, Ti, Hf, V, Ta, Cr, W, Ru, Cu, In, Si, Eu.

Preferably, the nonmagnetic spacer layer is a metal or an alloy, and the constituent elements of the metal or the alloy are selected from one or more of Cu, Ag, Au, Al, Pt, Ta, Ti, Nb, Os, Ru, Rh, Y, Mg, Pd, Cr, W, Mo, V.

Preferably, the nonmagnetic spacer layer is selected from, but not limited to, SiC and ceramic materials.

The invention has the beneficial effects that:

an asymmetric laminated structure "first conductive layer-antiferromagnetic layer-second conductive layer" (C1-AFM-C2) is formed using an antiferromagnetic material and a metallic material instead of a heavy metal layer used in a SHE MRAM to generate a spin-polarized current (in-bulk)When the total magnetic moment is zero, the generation of spin-polarized current can be caused due to the asymmetric interface of the asymmetric laminated structure), and C1/C2 can be a good conductor, so that compared with an SHE MRAM, the use of heavy metal with high resistivity can be avoided; ② the conductor 1 and the conductor 2 can be materials which are matched with the prior semiconductor technology and have low resistivity, such as Au, Ag, Cu, Al (Cu and Al are materials commonly used in the semiconductor technology) and the like, for example, the resistivity of Au is rho_Au2.20 μ Ω · cm, Ag resistivity ρ_Ag1.55 mu omega cm, and resistivity of Cu is rho_Cu1.70 μ Ω · cm, and resistivity of Al ρ_AlThe resistivity of a writing path is effectively reduced by 2.70 mu omega cm, so that the energy consumption is reduced, the heat generation is reduced, and the reliability and the stability of the device work are improved; and the spin conversion efficiency is equivalent to SHE and can reach 20 percent at present, and the advantage brought by using the spin current generator with the structure of the first conducting layer, the antiferromagnetic layer and the second conducting layer opens up a new space for the spin electronic device and the application thereof.

Drawings

FIG. 1A illustrates a three-terminal magnetic memory bit cell 100 according to one embodiment of the present disclosure.

FIG. 1B illustrates a top down view 120 of the magnetic memory bitcell 100 of FIG. 1A.

FIG. 1C illustrates a control circuit of a three-terminal magnetic memory device using a C1-AFM-C2 structure to generate spin-polarized current, represented in block diagram form 140, in accordance with one embodiment of the present disclosure.

FIG. 2A shows a schematic front view 200 of a magnetic memory bitcell, consistent with one embodiment of the present disclosure.

FIG. 2B shows a schematic top down view 220 of a magnetic memory bitcell, consistent with one embodiment of the present disclosure.

FIG. 3 illustrates the three interactions experienced during magnetic moment precession described by the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation.

FIG. 4 illustrates an asymmetric stacked structure of C1-AFM-C2, according to one embodiment of the present disclosure.

FIG. 5 shows a schematic cross section 500 of an exemplary C1-AFM-C2 structure for generating spin-polarized current, according to one embodiment of the present disclosure.

Fig. 6 shows a graph 600 of the variation of the magnetic moment M at different positions along the stacking direction (+ z direction) in the material layers of the Au-Cr-Ag structure shown in fig. 5.

FIG. 7 shows the total magnetic moment M of the Au-Cr-Ag structure shown in FIG. 5_tot Curve 700 versus accumulation of Cr atomic layers (Cr atomic layer index N).

Fig. 8 shows a graph 800 of conductance G versus accumulation of Cr atomic layers (Cr atomic layer index N) for the Au-Cr-Ag structure shown in fig. 5.

FIG. 9 shows a plot 900 of polarization P versus accumulation of Cr atomic layers (Cr atomic layer index N) for the Au-Cr-Ag structure shown in FIG. 5.

Detailed Description

The following exemplary embodiments relate to circuits and devices having magnetic materials or structures and applications thereof, and more particularly, but not by way of limitation, to spin-polarized current generators and magnetic devices thereof.

FIG. 1A shows a magnetic device according to one embodiment of the disclosure, and for clarity, FIG. 1A and any other figures of the disclosure are not drawn to scale. The magnetic device is a three-terminal magnetic memory bit cell 100 described using a "first conductive layer-antiferromagnetic layer-second conductive layer" (referred to as "C1-AFM-C2") asymmetric stacked structure as a spin polarized current generator. The magnetic device includes a first conductive layer C1120, and two stacked structures of an antiferromagnetic layer (AFM layer) (i.e., the second antiferromagnetic layer 140, the first antiferromagnetic layer 130) and a second conductive layer (the left second conductive layer C2142, the right second conductive layer C2132) on the first conductive layer C1120, wherein the first conductive layer C1120 is adjacent to the left antiferromagnetic layer 140 and the right antiferromagnetic layer 130; a magnetic junction is disposed on the first conductive layer C1120 between the two stacked structures, wherein the magnetic junction 110 includes the free magnetic layer 112 in the present embodiment. In still other embodiments, the magnetic junction MJ 110 includes a free magnetic layer 112, a fixed magnetic layer 116, and a nonmagnetic spacer layer 114 between the free magnetic layer and the fixed magnetic layer.

The Magnetic Junction (MJ)110 may be part of a memory cell, which may also include a selection device such as a transistor and/or other magnetic junctions. In the case of an overall system magnetic moment of zero, spin-polarized current generation may be caused due to the interfacial asymmetry of the asymmetric laminated structure C1-AFM-C2. When current passes through at least one of the stacked structures to the first conductive layer structure, the spin-polarized current generated exerts a spin torque on the free magnetic layer; when no current flows, no spin-polarized current is generated.

In other embodiments, the three-terminal magnetic memory bit cell 100 includes a magnetic junction 110 and at least one C1-AFM-C2 structure.

In the present embodiment, an "asymmetric stack structure of first conductive layer-antiferromagnetic layer-second conductive layer" is used to switch the magnetic moment orientation of the free magnetic layer 112. Wherein the C1120, the first AFM layer 130 and the first C2132 are stacked together to form a first C1-AFM-C2 structure, and the C1120, the second AFM layer 140 and the second C2142 are stacked together to form a second C1-AFM-C2 structure. The "first AFM layer 130-first C2132" stack and the "second AFM layer 140-second C2142" stack are disposed to the right and left of the magnetic junction 110, respectively. In the present embodiment, the first conductive layer C1120 shared by the first and second C1-AFM-C2 structures is in direct contact with the free magnetic layer 112. In some embodiments, there may be an intermediate layer between the first conductive layer C1 and the free magnetic layer.

In some embodiments, the current flowing through the first and second C1-AFM-C2 structures is caused to have different spin polarizations by adjusting the thicknesses of the first and second AFM layers. In other embodiments, the first and second C2 are made of different conductive materials, so that the current flowing through the first and second C1-AFM-C2 structures has different spin polarization.

AFM layers of C1-AFM-C2 structure have a composition defined by a Neel temperature (Neel temperature or magnetic ordering temperature T)_NAntiferromagnetic materials exhibit paramagnetism above the neel temperature) above room temperature.

In some embodiments, the AFM layer is made of a single layer of a metal selected from, but not limited to, Cr.

In other embodiments, the AFM layer is made of a single layer of an alloy selected from, but not limited to, CoRh, ferah.

In other embodiments, the AFM layer is made of a single layer of a Cr-based alloy selected from, but not limited to: CrV, CrMn, CrRe, CrFe, CrRu, CrOs, CrCo, CrRh, CrIr, CrNi, CrPd, CrPt, CrCu, CrAg, CrAu, CrGa, CrIn, CrMnPt, FeNiCr.

In other embodiments, the AFM layer is made of a single layer of a Mn-based alloy selected from, but not limited to: CrMn, ReMn, FeMn, RuMn, OsMn, CoMn, RhMn, IrMn, NiMn, PdMn, PtMn, CuMn, AgMn, AuMn, PdPtMn, CoCrMn.

In other embodiments, the AFM layer is made of a single layer of a NiFeCrCo-based alloy.

In other embodiments, the AFM layer is made of rare earth metals and alloys thereof selected from one or more of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.

In other embodiments, the AFM layer is made of a rare earth metal alloy including rare earth metals and conventional metals selected from one or more of, but not limited to, Y, Fe, Ni, Pd, Al, In, Gd, Sn.

In other embodiments, the AFM layer is made of a composite layer of materials made of Synthetic Antiferromagnetic (SAF) materials, the SAF layer being made of ferromagnetic layers selected from, but not limited to, Fe, Co, CoFe, Ni, CoCrPt, CoFeB, (Co/Ni)_p、(Co/Pd)_m、(Co/Pt)_nWhere m, n, p refer to the number of repetitions of the multilayer stack, and the spacer layer is selected from one or more of Nb, Ta, Cr, Mo, W, Re, Ru, Os, Rh, Ir, Pt, Cu, Ag, Au, but not limited thereto.

In some embodiments, the first and second conductive layers of the C1-AFM-C2 structure are made of different materials to form an asymmetric stack for generating spin-polarized current.

The first and second conductive layers of the C1-AFM-C2 structure of the present invention are made of different conductive materials, and are selected from one or more of, but not limited to, Li, Mg, Al, Ca, Sc, Ti, V, Mn, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Po, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb. The first conductive layer C1 needs to have a low resistivity and a large spin diffusion length.

The thickness of the antiferromagnetic layer is 0.1 nm-10 nm; the thickness of the first conducting layer is 1 nm-100 nm; the thickness of the second conducting layer is 1 nm-100 nm; the thickness of the first conductive layer and the thickness of the second conductive layer may be the same or different.

The above embodiments use AFM layers, first conductive layers and second conductive layers made of different materials, all of which can spin-polarize the current flowing through the C1-AFM-C2 structure.

As shown in fig. 1A, in the present embodiment, the first C2132 forms a first electrical terminal, the second C2142 forms a second electrical terminal, and the fixed magnetic layer 116 is directly or indirectly connected to a third electrical terminal. The current flowing into the first conductive layer C1120 through the "first C2132-first antiferromagnetic layer 130" or the "second C2142-second antiferromagnetic layer 140" generates spin polarization, in which electrons or other charge carriers having the same spin polarization direction can diffuse into the free magnetic layer 112, and the spin transfer torque provided by the spin polarized electrons can rapidly deflect the magnetic moment of the free magnetic layer 112 from its initial equilibrium state (e.g., parallel to the easy axis) to a desired direction.

In this embodiment, the magnetic junction includes a free magnetic layer 112. The free magnetic layer may be a single layer of magnetic material or a composite layer of different materials, such as a "ferromagnetic layer-nonmagnetic layer (e.g., Ru) -ferromagnetic layer" composite layer.

In some embodiments, the free magnetic layer 112 is made of a ferromagnetic or ferrimagnetic metal and alloys thereof selected from, but not limited to, Fe, Co, Ni, Mn, NiFe, FePd, FePt, CoFe, CoPd, CoPt, YCo, LaCo, PrCo, NdCo, SmCo, CoFeB, BiMn, NiMnSb, and combinations thereof with one or more metals of B, Al, Zr, Hf, Nb, Ta, Cr, Mo, Pd, Pt.

In other embodiments, the free magnetic layer 112 is made of a synthetic ferromagnetic or ferrimagnetic material selected from, but not limited to, 3d/4d/4f/5d/5 f/rare earth metal layer stacked artificial multilayer structures Co/Ir, Co/Pt, Co/Pd, CoCr/Pt, Co/Au, Ni/Co.

In other embodiments, the free magnetic layer 112 is made of a half-metal ferromagnetic material including a form of XYZ or X₂Heusler alloys of YZ, where X is selected from, but not limited to, one or more of Mn, Fe, Co, Ni, Pd, Cu, Y is selected from, but not limited to, one or more of Ti, V, Cr, Mn, Fe, Co, Ni, and Z is selected from, but not limited to, one or more of Al, Ga, In, Si, Ge, Sn, Sb.

In other embodiments, the free magnetic layer 112 is made of Synthetic Antiferromagnetic (SAF) material, which is used to make a free magnetic layer consisting of ferromagnetic layers and spacer layers; the ferromagnetic layer material comprising the free magnetic layer is selected from, but not limited to, Fe, Co, CoFe, Ni, CoCrPt, CoFeB, (Co/Ni)_p、(Co/Pd)_m、(Co/Pt)_nWherein m, n, p refer to the number of repetitions of the multilayer stack; the spacer layer material constituting the free magnetic layer is selected from one or more of Nb, Ta, Cr, Mo, W, Re, Ru, Os, Rh, Ir, Pt, Cu, Ag, Au, but not limited thereto.

In other embodiments, the magnetic junction further includes a fixed magnetic layer 116, and a nonmagnetic spacer layer 114 between the free magnetic layer 112 and the fixed magnetic layer 116, the free magnetic layer for data storage.

The fixed magnetic layer 116 and the free magnetic layer 112 are made of the same material, and the thicknesses of the fixed magnetic layer 116 and the free magnetic layer 112 may be different. In some embodiments, the free magnetic layer 112 and the fixed magnetic layer 112 are electrically conductive.

In some embodiments, the nonmagnetic spacer layer 114 is an insulating tunnel barrier layer and the nonmagnetic spacer layer is an oxide, nitride, or oxynitride material having a constituent element selected from, but not limited to, one or more of Mg, B, Al, Ca, Sr, La, Ti, Hf, V, Ta, Cr, W, Ru, Cu, In, Si, Eu.

In other embodiments, the nonmagnetic spacer layer 114 is a conductive layer that is a metal or alloy with constituent elements selected from, but not limited to, one or more of Cu, Ag, Au, Al, Pt, Ta, Ti, Nb, Os, Ru, Rh, Y, Mg, Pd, Cr, W, Mo, V.

In other embodiments, the nonmagnetic spacer layer 114 is selected from, but not limited to, SiC and ceramic materials.

In other embodiments, the spacer layer 114 may have other structures, such as a granular layer (a granular layer including conductive channels in an insulating matrix) that is proposed in "Method and system for providing a magnetic tunneling using a spin-interference based switching and a dielectric using the magnetic tunneling junction" (U.S. Pat. No. 9,076,537).

The above-described embodiments employ different materials for the free magnetic layer 112 and the fixed magnetic layer 116 that are ferromagnetic, while the spacer layer 114 is nonmagnetic.

In other embodiments, the magnetic junction 110 further includes a pinning layer (not shown) for pinning the magnetic moment of the fixed magnetic layer 116. In some embodiments, the magnetic moment of the fixed magnetic layer 116 is otherwise fixed. In some embodiments, the magnetic moments of the free magnetic layer 112 and the fixed magnetic layer 116 are in-plane. In some embodiments, the magnetic moments of the free magnetic layer 112 and the fixed magnetic layer 116 are perpendicular to the plane.

In some embodiments, only the spin-polarized current generated by the "first conductive layer-antiferromagnetic layer-second conductive layer" structure is used to provide the necessary magnitude of spin-transfer torque for magnetization switching of the free magnetic layer 112. In the present embodiment, the spin-polarized current generated by the current flowing through the path "first C2132-first antiferromagnetic layer 130-C1120-second antiferromagnetic layer 140-second C2142" is used to provide a spin transfer torque for switching the magnetic moment orientation of the free magnetic layer 112.

As shown in FIG. 1A, a write current is spin-polarized through the "first C2-first antiferromagnetic layer" or "second C2-second antiferromagnetic layer" stack and then flows into the first conductive layer C1120, where electrons or other charge carriers having the same spin polarization direction can diffuse into the free magnetic layer 112, thereby generating a spin-transfer torque for the magnetic moment of the free magnetic layer 112

(spin torque generated by spin reservoir) the spin transfer torque corresponds to an equivalent field applied to the free magnetic layer 112

(effective field generated by spin cuerent)，

Thus, the electron spin polarization induced by the injection of current into the C1-AFM-C2 structure can be equivalently described as applying an external magnetic field to the free magnetic layer 112.

By adjusting the materials and dimensions of the various layers in the MJ 110 and C1-AFM-C2 structures, the desired interfacial electron coupling is provided between the free magnetic layer and the first conductive layer C1 to allow (given the current flowing through the C1-AFM-C2 structure) more spin-polarized electrons or other charge carriers to diffuse from the first conductive layer C1 into the free magnetic layer.

The operation of the magnetic device is given below.

In the present embodiment, the write path is "first C2132-first antiferromagnetic layer 130-first conductive layer C1120-second antiferromagnetic layer 140-second C2142", along which the write current can flow in the forward or reverse direction. To illustrate with a forward write current, a current through "first C2132-first antiferromagnetic layer 130" creates a spin polarization, and then when flowing in the plane of the first conductive layer C1120, electrons or other charge carriers with the same spin polarization direction diffuse into the free magnetic layer 112, which creates a spin transfer torque that flips the magnetization in the free magnetic layer 112. By applying a forward or reverse current, MJ can be switched to either a low resistance state or a high resistance state, thereby writing data to memory cell 100. In some embodiments, the write path is "first C2-first AFM layer-C1" along which the write current can flow in either a forward or reverse direction.

The following describes a read process of the memory cell 100. In the present embodiment, the read path is "magnetic junction 110-first conductive layer 120-first antiferromagnetic layer 130-first C2132" or "magnetic junction 110-first conductive layer 120-second antiferromagnetic layer 140-second C2142". In some embodiments, the read path is "magnetic junction 110 — first conductive layer C1," which first conductive layer C1 is coupled to a second electrical terminal (not shown) of the three-terminal magnetic memory. In some embodiments, the read current through MJ is sensed using an amplifier. In this embodiment, the read and write paths are decoupled to provide the advantages of better technical control and read and write processes.

FIG. 1B illustrates a top down view 120 of the magnetic memory bitcell 100 of FIG. 1A. As shown in FIGS. 1A-1B, the magnetic moments of the fixed magnetic layer 116 and the free magnetic layer 112 are perpendicular to the plane (the x-y plane). In some embodiments, the MJ may have a circular cross-section for ease of technical fabrication, since the silicon substrate used in the industry for growing MJ is mostly circular. In some embodiments, the MJ may have an elliptical, rectangular, square, or any other shape in cross-section as desired. In the present embodiment, the first and second C1-AFM-C2 structures are disposed on the right and left sides of the magnetic junction 110, respectively. In the present embodiment, the first conductive layer C1120 is shared by the first and second antiferromagnetic layers of the first and second C1-AFM-C2 structures. The second conductive layers of the first and second C1-AFM-C2 structures are referred to as first C2132 and second C2142, respectively.

In some embodiments, currents flowing through the first and second C1-AFM-C2 structures produce different spin polarizations by adjusting the thicknesses of the first and second AFM layers and the magnetization distributions therein (e.g., the first AFM layer has an "up-down-up-down" magnetization distribution in the stacking direction, and the second AFM layer has a "down-up" magnetization distribution in the same stacking direction). The spin polarization direction of the electrons or other charge carriers flowing in C1120 is determined by the write current selection whether to inject C1120 through the "first C2132-first AFM layer 130" or the "second C2142-second AFM layer 140". For example, as shown in FIGS. 1A-1B, with the magnetization of the pinned layer 116 up (in the + z direction), the magnetization distribution in the first AFM layer can be set such that the write current flowing through the "first C2132-first AFM layer 130" is spin polarized in the + z direction to write a logical 1 (parallel magnetization state) to MJ, while the magnetization distribution in the second AFM layer is set such that the write current flowing through the "second C2142-second AFM layer 140" is spin polarized in the-z direction to write a logical 0 (anti-parallel magnetization state) to MJ.

FIG. 1C illustrates a control circuit of a three-terminal magnetic memory device using a C1-AFM-C2 structure to generate spin-polarized current, represented in block diagram form 140, in accordance with one embodiment of the present disclosure. In this embodiment, the first and second C2 form first and second electrical terminals, the fixed magnetic layer is coupled to a third electrical terminal, and the memory control circuitry is coupled to the first, second and third electrical terminals to implement the desired data writing and reading functions.

(1) The control circuit is used to write data to MJ by selecting the first and second electrical terminals to drive current to flow (forward or reverse) along the write path "second C2-second AFM layer-C1-first AFM layer-first C2" to generate spin-polarized electrons or other charge carriers in the C1 layer that diffuse into the free magnetic layer, switching the magnetization orientation of the free magnetic layer with an induced spin-transfer torque;

(2) the control circuitry is used to read data from MJ, sense the magnetization state of MJ by driving currents using the first and third electrical terminals along the read path "pinned magnetic layer-nonmagnetic spacer layer-free magnetic layer-C1-first AFM layer-first C2", or driving currents using the second and third electrical terminals along the read path "pinned magnetic layer-nonmagnetic spacer layer-free magnetic layer-C1-second AFM layer-second C2".

A three-terminal magnetic memory device using a C1-AFM-C2 structure to generate spin-polarized current is provided with a write or read function by selecting a write line connected between the second electrical terminal and the control circuit or a read line connected between the third electrical terminal and the control circuit, which forms a closed write circuit or read circuit with a wire connected between the first electrical terminal and the control circuit.

FIGS. 2A and 2B show schematic front and

top views

200 and 220 of a magnetic memory bitcell, consistent with one embodiment of the present disclosure. The MJ 210 may be part of a memory cell that may also include a selection device such as a transistor and/or other magnetic junction. For clarity, FIGS. 2A-2B and any other figures in this document are not drawn to scale.

In this embodiment, the fixed magnetic layer and the free magnetic layer of MJ 210 are magnetized in-plane, and an "first conductive layer-antiferromagnetic layer-second conductive layer" asymmetric stack is used to switch the magnetic moment orientation of the free magnetic layer 212. In some embodiments, currents flowing through the first and second C1-AFM-C2 structures produce different spin polarizations by adjusting the thicknesses of the first and second AFM layers and the magnetization distributions therein (e.g., the first AFM layer has a magnetization distribution of "left-right-left-right" in the stacking direction, and the second AFM layer has a magnetization distribution of "right-left-right-left" in the same stacking direction). The spin polarization direction of the electrons or other charge carriers flowing in the C1220 is determined by the write current selection to inject the C1220 through the "first C2232-first AFM layer 230" or the C1220 through the "second C2242-second AFM layer 240". For example, as shown in FIGS. 2A-2B, the magnetization of the fixed magnetic layer 216 is in the-y direction, the magnetization distribution in the first AFM layer can be set such that the write current flowing through the "first C2232-first AFM layer 230" is spin-polarized in the-y direction to write a logical 1 (parallel magnetization state) to MJ, while the magnetization distribution in the second AFM layer is set such that the write current flowing through the "second C2242-second AFM layer 240" is spin-polarized in the + y direction to write a logical 0 (anti-parallel magnetization state) to MJ.

FIG. 3 shows Landau-Lifshitz-Gilbert-Slonczewski (L)LGS) equation formula (1) describes the three interactions that a magnetic moment undergoes during precession: a precession term, a damping term, and a spin-transfer torque (so-called STT) term. The magnetic moment M of the free magnetic layer in FIGS. 1A-1C and FIGS. 2A-2B is equal and opposite if the damping moment and the STT are equal and opposite_freeWill be in a steady precessional state with a precessional trajectory as indicated by the dashed circle in fig. 3.

Fig. 4 shows an asymmetric stacked structure of C1-AFM-C2, where the total magnetic moment of the system is zero, and the magnetizations of the "first conductive layer-antiferromagnetic layer" interface and the "antiferromagnetic layer-second conductive layer" interface increase to different degrees due to the asymmetry of the interfaces of the asymmetric stacked structure, so that a net magnetization is generated, and the C1-AFM-C2 structure shows ferromagnetism as a whole, so that a current flowing through the C1-AFM-C2 structure may generate spin polarization. The C1-AFM-C2 structure can be used as a novel spin polarized current generator and is used in magnetic devices such as a magnetic memory and a magnetic logic device, and for example, the spin polarized current generator can replace a high-resistivity heavy metal layer in a spin Hall effect magnetic random access memory (called SHE MRAM) to generate spin polarized current.

FIG. 5 shows a schematic cross-section 500 of an exemplary C1-AFM-C2 structure for generating spin-polarized current, where the AFM layer made of Cr is a spin-transported scattering region, the first conductive layer is made of Au, and the second conductive layer is made of Ag, according to one embodiment of the present disclosure. In the case where the total magnetic moment of the system is zero, spin-polarized current may be generated due to the interface asymmetry of the Au-Cr-Ag asymmetric laminated structure.

The requirements calculated according to first principles divide the structure into atomic layers, also called main layers, with the atomic layer index marked on the right side of the structure, thereby creating a quasi-one-dimensional tightly bound model of the exemplary C1-AFM-C2 structure Au-Cr-Ag, transport along the + z direction, and x-y plane perpendicular to the transport direction. DieThe transport problem is solved by utilizing a wake wave elimination equation. Since each atomic layer divided for the structure is sufficiently thick, only the interaction between adjacent atomic layers is considered, ignoring the coupling between other layers. The system has two-dimensional translation invariance in a plane (O-x-y plane) vertical to the conveying direction (+ z direction), and the eigenstate of the system can be a two-dimensional Brillouin zone transverse wave vector

To express that the equation of motion (KKR equation) of the I atomic layer under the mixed expression is

Wherein

Fourier transform of amplitude of I atomic layer with system inverse space structure constant as real space structure constant

Wherein { T_I,JRepresents a vector where one lattice point of the I-th layer is connected to all lattice points of the J-th layer. In any scattering state of an ideal electrode, Block wave functions of electrodes on two sides are deduced by using Block factors, then wave function matching is carried out in a middle scattering area to obtain a wave function of the middle scattering area, a motion equation of a boundary atomic layer (a 0 th layer and an (N + 1) th layer) of the middle scattering area is deduced, and infinite motion equations describing scattering problems are cut into a finite number of equation sets through the two boundary conditions:

c is to be₀And C_N+1According to the eigenmode expansion under the respective localized quantization axis in the electrodes and considering the relative magnitude of the current carried by the corresponding eigenmode, the eigenmodes propagating under the respective localized quantization axis on the two electrodes can be obtainedA transmission matrix element between, e.g. having a transmission coefficient from lower electrode mode upsilon to upper electrode mode upsilon of

Wherein the group velocity of the eigenmodes is

Wherein

Is the distance between the equivalent atoms in two adjacent atomic layers. After obtaining the transmission coefficient and the reflection coefficient, the conductance G of the system can be determined:

the first principle calculation method is successfully applied to a plurality of scientific fields such as physics, chemistry, biology and the like, and is an important means for researching nano system materials. For example, (2011) Xing-tao Jia et al studied the field of spintronics for magnetic insulators by first-order principle calculations, predicted the order of magnitude of the spin transfer torque at the interface of the normal metal and the magnetic insulator, and calculated the spin-mixed conductance G of the silver and insulating ferromagnet Yttrium Iron Garnet (Yttrium Iron Garnet, referred to as YIG) interface using a local spin model^↓↑(10¹⁴Ω^-1m^-2) Using Schep corrected Ag | Fe₄|YIG|Fe₄Spin-mixed conductance G of | Ag (001)^↓↑≈8.0×10¹⁴Ω^-1m^-2The result was calculated from the spin-mixed conductance G of the S5 sample measured by B.Heinrich et al^↓↑＝5.0×10¹⁴Ω^-1m^-2Close; (2014) Shi-Zhuo Wang et al studied the thermoelectricity and interfacial disorder of "multiphase alloy FeCo/MgO/FeCo (001)" MTJ by the same method, calculated the Seebeck coefficient S, conductance G_σThe thermal conductivity κ and other thermoelectric parameters were compared with the corresponding experiments (good agreement between theoretical calculation and experimental measurement) and, as shown in fig. 2 of the literature (Shi-Zhuo Wang, Ke Xia, and Gerrit e.w.bauer, 2014), RA ═ 23.8 Ω · μm was calculated for a magnetic tunnel junction in which the MgO barrier layer is 7 monolayers thick (1.6nm) and the magnetic moments of the free layer and the pinned layer are oriented in parallel²(void free) and RA ═ 12 Ω · μm²(5% oxygen vacancies), close to the measurement RA of 17 Ω · μm in literature (n.liebing et al, 2011.) and literature (n.liebing et al, 2012.)²(the thickness of the barrier layer is 1.5nm), and the calculation result of the magnetic tunnel junction with the MgO barrier layer being 4-5 monolayers (1.0nm) is 0.4-1 omega-mum of the measured value RA reported in the literature (S.Yuasa and D.D.Djayaprawira,2007.)²Inosculating; (2016) Shi-Zhuo Wang et al investigated Fe caused by voltage and temperature gradients using the same method_0.5Co_0.5/MgO/Fe_0.5Co_0.5(001) The spin torque moment of MTJs was studied and the optimization of a small number of interfacial oxygen vacancies (called OV) on the "threshold voltage" of the in-plane STT, where a sample with an asymmetric OV distribution reproduced experimental measurements in the literature (C.Wang et al, 2011.) as shown in FIG. 5 in the literature (Shi-Zhuo Wang and Ke Xia,2016.) with a bias voltage of-0.1 V.ltoreq.V_bIn the range of less than or equal to 0.3V, the partial derivative of the spin transfer torque of the MTJ L5R0 to the bias voltage is calculated

Consistent with experimental (6 monolayers (6ML) thick MgO MTJ, asymmetric OV distribution at left and right interfaces) results; (2016) lei Wang et al investigated pure Pt and Py | Pt (Py ═ Ni) in temperature limited (finite temperature) using the same method₈₀Fe₂₀) Spin Hall Effect of bilayer film, a huge interface spin Hall angle due to spin-orbit coupling and disorder was found (the interface spin Hall angle characterizes the spin conversion efficiency at the interface, i.e., the magnitude of the total spin current generated by the unit current), and the spin Hall conductivity σ of Pt was calculated_SH＝1600Ω^-1cm^-1This is in contrast to intrinsic spin Hall conductivity (intrinsic spin Hall conductivity) of Pt, which is systematically measured and analyzed by Edure Sagasta et al

Are very consistent. The prediction of parameters such as spin transfer torque, TMR, thermoelectric effect, spin Hall effect and the like by the first principle is consistent with the above and other experimental results, and the correctness and the practicability of the calculation method of the first principle are fully proved.

In the present invention, the first principle calculation method is used for calculation of spin transport and spin transfer torque in the "first conductive layer-antiferromagnetic layer-second conductive layer" structure. Fig. 6 shows a graph 600 of the variation of magnetic moment M at different positions along the stacking direction (+ z direction) in the respective material layers of the Au-Cr-Ag structure shown in fig. 5, which is an exemplary C1-AFM-C2 structure for generating spin-polarized current, and the Cr atomic layer index N is even to exhibit antiferromagnetic property. It can be seen that the magnetic moment of the antiferromagnetic Cr layer is abruptly changed at the Au-Cr interface and the Cr-Ag interface, and increased in opposite directions (+2.1 μm)_B，-1.9μ_B) While the internal magnetic moment of the Cr layer is not affected by the adjacent Au layer and Ag layer (minus or plus 0.65 mu)_B). By selecting the materials or other parameters of the two adjacent layers of the antiferromagnetic layer, the degree of magnetic moment increase at the two interfaces can be respectively adjusted, for example, in the Au-Cr-Ag structure of fig. 5, the magnetic moments of the Au-Cr interface and the Cr-Ag interface are increased to different degrees, so that the Au-Cr-Ag structure as a whole shows certain ferromagnetism, and thus the ferromagnetism shown by the Au-Cr-Ag (C1-AFM-C2) structure can be utilized to generate spin-polarized current. In some embodiments, the magnetization profile of the Cr layer is such that the current is spin polarized in the +/-z direction after passing through the Au-Cr-Ag structure. In some embodiments, the magnetization profile of the Cr layer is such that the current is spin polarized in the +/-y direction after passing through the Au-Cr-Ag structure.

FIG. 7 shows the total magnetic moment M of the Au-Cr-Ag structure shown in FIG. 5_totThe change curve 700 with respect to the accumulation of Cr atomic layers (Cr atomic layer index N) shows that the total magnetic moment of the Au-Cr-Ag structure is 0.18 mu_BFluctuating up and down.

FIG. 8 showsFIG. 5 shows a graph 800 of conductance G versus accumulation of Cr atomic layers (Cr atomic layer index N) for an Au-Cr-Ag structure, where black square points indicate the conductance G in spin-up_↑White dots indicate spin-down conductance G_↓It can be seen that G_↑And G_↓All become smaller with the increase of the number of Cr atomic layers, and for N ≥ 4, G_↑And G_↓Is very close to the value, | G_↑-G_↓The | exists in 0 to 0.05e²A small difference of h (hA), and 2 for N, both appear at-0.18 e²A large difference (a represents a cross-sectional area of the Au — Cr — Ag structure perpendicular to the current flowing direction) and N is 2, the polarization P also takes a relatively large value, indicating that the degree of spin polarization is relatively large, so that the number of Cr atomic layers taken as 2 is a reasonable choice for the C1(Au) -afm (Cr) -C2(Ag) structure for generating spin-polarized current.

FIG. 9 shows a plot 900 of polarization P versus accumulation of Cr atomic layers (Cr atomic layer index N) for the Au-Cr-Ag structure shown in FIG. 5. It can be seen that the value of P fluctuates within ± 20% with the change in the number of Cr atomic layers, and when N is 8 and N is 14, | P | is large, from P | G_↑-G_↓|/(G_↑+G_↓) It can be seen that the degree of spin polarization is relatively large when N-8 and N-14.

FIG. 9 shows that the current flowing through the C1(Au) -AFM (Cr) -C2(Ag) structure has been spin polarized, so the C1-AFM-C2 structure can be used to flip the magnetic moment of the adjacent free magnetic layer to write data to the magnetic junction. For the embodiment shown in FIG. 1A, the write path is "first C2132-first AFM layer 130-C1120-second AFM layer 140-second C2142". Current injected into C1120 via either the "first C2132-first AFM layer 130" or the "second C2142-second AFM layer 140" creates spin polarization, wherein the spin transfer torque induced by electrons or other charge carriers diffusing from C1120 into FL 112 destabilizes the magnetization of FL 112 for switching the magnetization orientation of FL 112. The write current can flow along this path in either the forward or reverse direction, depending on the desired final state of the MJ 110 for data storage (parallel magnetization-low resistance state-binary 1, or anti-parallel magnetization-high resistance state-binary 0).

Claims

1. A magnetic device comprising a spin-polarized current generator, comprising a spin-polarized current generator and a magnetic junction;

the spin polarized current generator includes:

the anti-magnetic-field-induced polarization-type semiconductor device comprises a first conductive layer, a second conductive layer and an anti-ferromagnetic layer, wherein the anti-ferromagnetic layer is positioned between the first conductive layer and the second conductive layer, the first conductive layer, the second conductive layer and the anti-ferromagnetic layer form a first conductive layer-anti-ferromagnetic layer-second conductive layer asymmetric laminated structure, and when current passes through the asymmetric laminated structure, spin polarization can be generated; when no current flows, spin polarization current is not generated;

at least one stacked structure composed of an antiferromagnetic layer and a second conductive layer is arranged on the first conductive layer, and the antiferromagnetic layer is adjacent to the first conductive layer;

a magnetic junction is arranged on the first conductive layer adjacent to the stacked structure, and the magnetic junction comprises a free magnetic layer;

the spin-polarized current generated when current passes through at least one of the stacked structures to the first conductive layer exerts a spin torque on the free magnetic layer;

the magnetic moment of the free magnetic layer is switched using at least a spin torque applied by a spin-polarized current generated by a current passing through at least one of the stacked structures to a first conductive layer;

the antiferromagnetic layer of the laminated structure is a single-layer material or a composite layer composed of multiple materials, and the single-layer material includes metal, alloy or rare earth metal and alloy thereof; the composite layer is made of synthetic antiferromagnetic material, and the composite layer made of the synthetic antiferromagnetic material is composed of a ferromagnetic layer and a spacer layer.

2. A magnetic device formed by a spin-polarized current generator as claimed in claim 1, wherein the metal or alloy forming the single layer of material is selected from Cr, CoRh, FeRh, Cr-based alloys: CrV, CrMn, CrRe, CrFe, CrRu, CrOs, CrCo, CrRh, CrIr, CrNi, CrPd, CrPt, CrCu, CrAg, CrAu, CrGa, CrIn, CrMnPt, FeNiCr, Mn-based alloy: CrMn, ReMn, FeMn, RuMn, OsMn, CoMn, RhMn, IrMn, NiMn, PdMn, PtMn, CuMn, AgMn, AuMn, PdPtMn, CoCrMn, and NiFeCrCo-based alloys;

the rare earth metal and the alloy thereof are selected from one or more of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu;

the rare earth metal alloy comprises rare earth metal and conventional metal, wherein the conventional metal is selected from one or more of Y, Fe, Ni, Pd, Al, In, Gd and Sn.

3. The magnetic device of claim 1, wherein the ferromagnetic layer of the composite layer is selected from the group consisting of Fe, Co, CoFe, Ni, CoCrPt, CoFeB, (Co/Ni)_p、(Co/Pd)_m、(Co/Pt)_nWherein m, n, p refer to the number of repetitions of the multilayer stack;

the spacer layer material of the composite layer is one or more of Nb, Ta, Cr, Mo, W, Re, Ru, Os, Rh, Ir, Pt, Cu, Ag and Au.

4. The magnetic device of claim 1, wherein the first and second conductive layers are selected from the following different metals or alloy materials:

5. The magnetic device of claim 1, wherein the antiferromagnetic layer has a thickness of 0.1nm to 10 nm; the thickness of the first conducting layer is 1 nm-100 nm; the thickness of the second conducting layer is 1 nm-100 nm;

the thickness of the first conductive layer and the thickness of the second conductive layer may be the same or different.

6. The magnetic device of claim 1, wherein the first conductive layer is shared by one or more of the stacked structures and the first conductive layer is shared by one or more of the magnetic junctions.

7. The magnetic device of claim 1, wherein the second conductive layer of the at least one stacked structure is made of different conductive materials to generate spin currents having different polarizations;

8. A magnetic device of a spin-polarized current generator as claimed in claim 1, wherein the free magnetic layer is made of a ferromagnetic or ferrimagnetic metal and its alloys selected from Fe, Co, Ni, Mn, NiFe, FePd, FePt, CoFe, CoPd, CoPt, YCo, LaCo, PrCo, NdCo, SmCo, CoFeB, BiMn, NiMnSb, and combinations thereof with one or more metals of B, Al, Zr, Hf, Nb, Ta, Cr, Mo, Pd, Pt;

or the free magnetic layer is made of synthetic ferromagnetic or ferrimagnetic material selected from the group consisting of 3d/4d/4f/5d/5 f/rare earth metal layer stacked artificial multilayer structure Co/Ir, Co/Pt, Co/Pd, CoCr/Pt, Co/Au, Ni/Co;

or the free magnetic layer is made of a half-metallic ferromagnetic material including a ferromagnetic material of the form XYZ or X₂The Heusler alloy of YZ, wherein X is selected from one or more of Mn, Fe, Co, Ni, Pd and Cu, Y is selected from one or more of Ti, V, Cr, Mn, Fe, Co and Ni, and Z is selected from one or more of Al, Ga, In, Si, Ge, Sn and Sb;

or the free magnetic layer is made of synthetic anti-ferromagnetic material, and the free magnetic layer made of the synthetic anti-ferromagnetic material consists of a ferromagnetic layer and a spacer layer; the ferromagnetic layer material constituting the free magnetic layer is selected from the group consisting of Fe, Co, CoFe, Ni, CoCrPt, CoFeB, (Co/Ni)_p、(Co/Pd)_m、(Co/Pt)_nWherein m, n, p refer to the number of repetitions of the multilayer stack;

the spacer layer material constituting the free magnetic layer is one or more selected from Nb, Ta, Cr, Mo, W, Re, Ru, Os, Rh, Ir, Pt, Cu, Ag and Au.

9. The magnetic device of claim 1, wherein the magnetic moment of the free magnetic layer is perpendicular to the plane of the free magnetic layer;

or the magnetic moment of the free magnetic layer is in the plane of the free magnetic layer.

10. The magnetic device of claim 1, wherein the magnetic junction further comprises a fixed magnetic layer, and a nonmagnetic spacer layer between the free magnetic layer and the fixed magnetic layer, the free magnetic layer for data storage.

11. The magnetic device of claim 10 where the nonmagnetic spacer layer is an oxide, nitride or oxynitride material having constituent elements selected from one or more of Mg, B, Al, Ca, Sr, La, Ti, Hf, V, Ta, Cr, W, Ru, Cu, In, Si, Eu;

or the nonmagnetic spacing layer is metal or alloy, and the constituent elements of the metal or alloy are selected from one or more of Cu, Ag, Au, Al, Pt, Ta, Ti, Nb, Os, Ru, Rh, Y, Mg, Pd, Cr, W, Mo and V;

or the nonmagnetic spacer layer is selected from SiC and ceramic materials.