Multiferroic tunnel junctions(MFTJs),which combine tunneling magnetoresistance(TMR)and electroresistance(TER)efects,have emerged as key candidates for data storage.Two-dimensional van der Waals(vdW)MFTJs,in particular...Multiferroic tunnel junctions(MFTJs),which combine tunneling magnetoresistance(TMR)and electroresistance(TER)efects,have emerged as key candidates for data storage.Two-dimensional van der Waals(vdW)MFTJs,in particular,are promising spintronic devices for the post-Moore era.However,these vdW MFTJs are typically based on multiferroics composed of ferromagnetic and ferroelectric materials or multilayer magnetic materials with sliding ferroelectricity,which increases device fabrication complexity.In this work,we design a vdW MFTJ using bilayer MoPtGe_(2)S_(6),a material with homologous multiferroicity in each monolayer,combined with symmetric PtTe_(2)electrodes.Using frst-principles calculations based on density functional theory and nonequilibrium Green's functions,we theoretically explore the spin-polarized electronic transport properties of this MFTJ.By controlling the ferroelectric and ferromagnetic polarization directions of bilayer MoPtGe_(2)S_(6),the MFTJ can exhibit six distinct non-volatile resistance states,with maximum TMR(137%)and TER(1943%)ratios.Under biaxial strain,TMR and TER can increase to 265%and 4210%,respectively.The TER ratio also increases to 2186%under a 0.1 V bias voltage.Remarkably,the MFTJ exhibits a pronounced spin-fltering and a signifcant negative diferential resistance efect.These fndings not only highlight the potential of monolayer multiferroic MoPtGe_(2)S_(6)for MFTJs but also ofer valuable theoretical insights for future experimental investigations.展开更多
We predict high-velocity magnetic domain wall(DW)motion driven by out-of-plane acoustic spin in surface acoustic waves(SAWs).We demonstrate that the SAW propagating at a 30-degree angle relative to the x-axis of a 128...We predict high-velocity magnetic domain wall(DW)motion driven by out-of-plane acoustic spin in surface acoustic waves(SAWs).We demonstrate that the SAW propagating at a 30-degree angle relative to the x-axis of a 128∘Y-LiNbO_(3) substrate exhibits uniform out-of-plane spin angular momentum.This acoustic spin triggers the DW motion at a velocity exceeding 50 m/s in a way that is similar to the spin-transfer-torque effect.This phenomenon highlights the potential of acoustic spin in enabling rapid DW displacement,offering an innovative approach to developing energy-efficient spintronic devices.展开更多
Magnetic two-dimensional(2D)van derWaals(vdWs)materials and their heterostructures attract increasing attention in the spintronics community due to their various degrees of freedom such as spin,charge,and energy valle...Magnetic two-dimensional(2D)van derWaals(vdWs)materials and their heterostructures attract increasing attention in the spintronics community due to their various degrees of freedom such as spin,charge,and energy valley,which may stimulate potential applications in the field of low-power and high-speed spintronic devices in the future.This review begins with introducing the long-range magnetic order in 2D vdWs materials and the recent progress of tunning their properties by electrostatic doping and stress.Next,the proximity-effect,current-induced magnetization switching,and the related spintronic devices(such as magnetic tunnel junctions and spin valves)based on magnetic 2D vdWs materials are presented.Finally,the development trend of magnetic 2D vdWs materials is discussed.This review provides comprehensive understandings for the development of novel spintronic applications based on magnetic 2D vdWs materials.展开更多
We design a Blatter radical-based molecular spintronic device, and investigate its spin-polarized transport properties using density functional theory and non-equilibrium Green's function technique. High-performan...We design a Blatter radical-based molecular spintronic device, and investigate its spin-polarized transport properties using density functional theory and non-equilibrium Green's function technique. High-performance spin-rectifying and spin-filtering effects are realized. The physical mechanism is explained by the spin-resolved bias voltage-dependent transmission spectra, the energy levels of the corresponding molecular projected self-consistent Hamiltonian orbitals, and their spatial distributions. The results demonstrate that the Blatter radical has great potential in the development of highperformance multifunctional molecular spintronic devices.展开更多
Using Fe, Co or Ni chains as electrodes, we designed several annulene-based molecular spintronic devices and investigated the quantum transport properties based on density functional theory and non-equilibrium Green＇...Using Fe, Co or Ni chains as electrodes, we designed several annulene-based molecular spintronic devices and investigated the quantum transport properties based on density functional theory and non-equilibrium Green＇s function method.Our results show that these devices have outstanding spin-filter capabilities and exhibit giant magnetoresistance effect,and that with Ni chains as electrodes, the device has the best transport properties. Furthermore, we investigated the spinpolarized optoelectronic properties of the device with Ni electrodes and found that the spin-polarized photocurrents can be directly generated by irradiating the device with infrared, visible or ultraviolet light. More importantly, if the magnetization directions of the two electrodes are antiparallel, the photocurrents with different spins are spatially separated, appearing at different electrodes. This phenomenon provides a new way to simultaneously generate two spin currents.展开更多
The electronic structures of spinel MgAl 2 O 4 and MgOtunnel barrier materials were investigated using first-principles density functional theory calculations. Our results show that similar electronic structures are f...The electronic structures of spinel MgAl 2 O 4 and MgOtunnel barrier materials were investigated using first-principles density functional theory calculations. Our results show that similar electronic structures are found for the MgAl 2 O 4 and MgO tunneling barriers. The calculated direct energy gaps at the Γ-point are about 5.10 eV for MgAl 2 O 4 and 4.81 eV for MgO, respectively. Because of the similar feature in band structures from Γ high-symmetry point to F point ( band), the coherent tunneling effect might be expected to appear in MgAl 2 O 4-based MTJs like in MgO-based MTJs. The small difference of the surface free energies of Fe (2.9 J m 2 ) and MgAl 2 O 4 (2.27 J m 2 ) on the {100} orientation, and the smaller lattice mismatch between MgAl 2 O 4 and ferromagnetic electrodes than that between MgO and ferromagnetic electrodes, the spinel MgAl 2 O 4 can substitute MgO to fabricate the coherent tunneling and chemically stable magnetic tunnel junction structures, which will be applied in the next generation read heads or spintronic devices.展开更多
We investigated the angle-dependent spin wave spectra of permalloy ring arrays with the fixed outer diameter and various inner diameters by ferromagnetic resonance spectroscopy and micromagnetic simulation.When the fi...We investigated the angle-dependent spin wave spectra of permalloy ring arrays with the fixed outer diameter and various inner diameters by ferromagnetic resonance spectroscopy and micromagnetic simulation.When the field is obliquely applied to the ring,local resonance mode can be observed in different parts of the rings.And the resonance mode will change to perpendicular spin standing waves if the magnetic field is applied along the perpendicular direction.The simulation results demonstrated this evolution and implied more resonance modes that maybe exist.And the mathematical fitting results based on the Kittel equation further proved the existence of local resonance mode.展开更多
Due to the upcoming demands of next-generation electronic/magnetoelectronic devices with low-energy consumption,emerging correlated materials（such as superconductors,topological insulators and manganites） are one of...Due to the upcoming demands of next-generation electronic/magnetoelectronic devices with low-energy consumption,emerging correlated materials（such as superconductors,topological insulators and manganites） are one of the highly promising candidates for the applications.For the past decades,manganites have attracted great interest due to the colossal magnetoresistance effect,charge-spin-orbital ordering,and electronic phase separation.However,the incapable of deterministic control of those emerging low-dimensional spin structures at ambient condition restrict their possible applications.Therefore,the understanding and control of the dynamic behaviors of spin order parameters at nanoscale in manganites under external stimuli with low energy consumption,especially at room temperature is highly desired.In this review,we collected recent major progresses of nanoscale control of spin structures in manganites at low dimension,especially focusing on the control of their phase boundaries,domain walls as well as the topological spin structures（e.g.,skyrmions）.In addition,capacitor-based prototype spintronic devices are proposed by taking advantage of the above control methods in manganites.This capacitor-based structure may provide a new platform for the design of future spintronic devices with low-energy consumption.展开更多
As a microwave generator, spin transfer nano-oscillator(STNO) based on skyrmion promises to become one of the next-generation spintronic devices. However, there still exist a few limitations to the practical applicati...As a microwave generator, spin transfer nano-oscillator(STNO) based on skyrmion promises to become one of the next-generation spintronic devices. However, there still exist a few limitations to the practical applications. In this paper, we propose a new STNO based on synthetic antiferromagnetic(SAF) skyrmion pair assisted by a perpendicular fixed magnetic field. It is found that the oscillation frequency of this kind of STNO can reach up to 5.0 GHz, and the multiple oscillation peak with higher frequency can be realized under a fixed out-of-plane magnetic field. Further investigation shows that the skyrmion stability is improved by bilayer antiferromagnetic coupling, which guarantees the stability process of skyrmion under higher spin-polarized current density. Our results provide the alternative possibilities for designing new skyrmionbased STNO to further improve the oscillation frequency, and realize the output of multiple frequency microwave signal.展开更多
Graphene nanoribbons(GNRs)are narrow strips of graphene with widths ranging from a few nanometers to a few tens of nanometers.GNRs possess most of the excellent properties of graphene,while also exhibiting unique phys...Graphene nanoribbons(GNRs)are narrow strips of graphene with widths ranging from a few nanometers to a few tens of nanometers.GNRs possess most of the excellent properties of graphene,while also exhibiting unique physical characteristics not found in graphene,such as an adjustable band gap and spin-polarized edge states.These properties make GNRs an appealing candidate for carbon-based electronics.In this review,we begin by introducing the edge geometry and electronic bands of GNRs.We then discuss various methods for fabricating GNRs and analyze the characteristics of each method.Subsequently,the performance of GNR field-effect transistor devices obtained from a few representative GNR fabrication methods is discussed and compared.We also investigate the use of GNRs as quantum dots and spintronic devices.Finally,the challenges and opportunities of GNRs as a quantum material for next-generation electronics and spintronics are explored and proposed.展开更多
Spintronics exploits magnetic order parameters to encode binary information and utilizes spin-dependent transport for data processing[1].To date,most spintronic devices have been based on ferromagnetic materials,which...Spintronics exploits magnetic order parameters to encode binary information and utilizes spin-dependent transport for data processing[1].To date,most spintronic devices have been based on ferromagnetic materials,which offer straightforward information writing and reading through manipulation and detection of their magnetization.A prototypical device is the magnetic tunnel junction(MTJ),where non-volatile memory readout is achieved via the tunneling magnetoresistance(TMR)effect—distinct resistance states arising from parallel and antiparallel alignments of ferromagnetic electrodes.MTJs serve as the building blocks of magnetic random-access memories(MRAMs),which have already found commercial applications.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFB3505301)the National Key R&D Program of Shanxi Province(Grant No.202302050201014)+1 种基金the National Natural Science Foundation of China(Grant No.12304148)the Natural Science Basic Research Program of Shanxi Province(Grant No.202203021222219)。
文摘Multiferroic tunnel junctions(MFTJs),which combine tunneling magnetoresistance(TMR)and electroresistance(TER)efects,have emerged as key candidates for data storage.Two-dimensional van der Waals(vdW)MFTJs,in particular,are promising spintronic devices for the post-Moore era.However,these vdW MFTJs are typically based on multiferroics composed of ferromagnetic and ferroelectric materials or multilayer magnetic materials with sliding ferroelectricity,which increases device fabrication complexity.In this work,we design a vdW MFTJ using bilayer MoPtGe_(2)S_(6),a material with homologous multiferroicity in each monolayer,combined with symmetric PtTe_(2)electrodes.Using frst-principles calculations based on density functional theory and nonequilibrium Green's functions,we theoretically explore the spin-polarized electronic transport properties of this MFTJ.By controlling the ferroelectric and ferromagnetic polarization directions of bilayer MoPtGe_(2)S_(6),the MFTJ can exhibit six distinct non-volatile resistance states,with maximum TMR(137%)and TER(1943%)ratios.Under biaxial strain,TMR and TER can increase to 265%and 4210%,respectively.The TER ratio also increases to 2186%under a 0.1 V bias voltage.Remarkably,the MFTJ exhibits a pronounced spin-fltering and a signifcant negative diferential resistance efect.These fndings not only highlight the potential of monolayer multiferroic MoPtGe_(2)S_(6)for MFTJs but also ofer valuable theoretical insights for future experimental investigations.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0103300)the open research fund of Songshan Lake Materials Laboratory(Grant No.2023SLABFN26)the Natural Science Foundation of Hubei Province(Grant No.2022CFA088)。
文摘We predict high-velocity magnetic domain wall(DW)motion driven by out-of-plane acoustic spin in surface acoustic waves(SAWs).We demonstrate that the SAW propagating at a 30-degree angle relative to the x-axis of a 128∘Y-LiNbO_(3) substrate exhibits uniform out-of-plane spin angular momentum.This acoustic spin triggers the DW motion at a velocity exceeding 50 m/s in a way that is similar to the spin-transfer-torque effect.This phenomenon highlights the potential of acoustic spin in enabling rapid DW displacement,offering an innovative approach to developing energy-efficient spintronic devices.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0206200)the National Natural Science Foundation of China(Grant No.11874409)+2 种基金the Beijing Natural Science Foundation,China(Grant No.Z190009)the Science Center of the National Science Foundation of China(Grant No.52088101)the K.C.Wong Education Foundation(Grant No.GJTD-2019-14).
文摘Magnetic two-dimensional(2D)van derWaals(vdWs)materials and their heterostructures attract increasing attention in the spintronics community due to their various degrees of freedom such as spin,charge,and energy valley,which may stimulate potential applications in the field of low-power and high-speed spintronic devices in the future.This review begins with introducing the long-range magnetic order in 2D vdWs materials and the recent progress of tunning their properties by electrostatic doping and stress.Next,the proximity-effect,current-induced magnetization switching,and the related spintronic devices(such as magnetic tunnel junctions and spin valves)based on magnetic 2D vdWs materials are presented.Finally,the development trend of magnetic 2D vdWs materials is discussed.This review provides comprehensive understandings for the development of novel spintronic applications based on magnetic 2D vdWs materials.
基金Project supported by the Natural Science Foundation of Shandong Province, China (Grant No. ZR2021MA059)。
文摘We design a Blatter radical-based molecular spintronic device, and investigate its spin-polarized transport properties using density functional theory and non-equilibrium Green's function technique. High-performance spin-rectifying and spin-filtering effects are realized. The physical mechanism is explained by the spin-resolved bias voltage-dependent transmission spectra, the energy levels of the corresponding molecular projected self-consistent Hamiltonian orbitals, and their spatial distributions. The results demonstrate that the Blatter radical has great potential in the development of highperformance multifunctional molecular spintronic devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1510132,U1610255,51401142,and 11604235)the Key Innovative Research Team in Science and Technology of Shanxi Province,China(Grant No.201605D131045-10)+2 种基金the Natural Science Foundation of Shanxi Province,China(Grant Nos.2015021027 and 2016021030)the Scientific and Technological Innovation Program of the Higher Education Institutions of Shanxi Province,China(Grant No.2016140)the Program for the Outstanding Innovative Teams of the Higher Learning Institutions of Shanxi Province,China
文摘Using Fe, Co or Ni chains as electrodes, we designed several annulene-based molecular spintronic devices and investigated the quantum transport properties based on density functional theory and non-equilibrium Green＇s function method.Our results show that these devices have outstanding spin-filter capabilities and exhibit giant magnetoresistance effect,and that with Ni chains as electrodes, the device has the best transport properties. Furthermore, we investigated the spinpolarized optoelectronic properties of the device with Ni electrodes and found that the spin-polarized photocurrents can be directly generated by irradiating the device with infrared, visible or ultraviolet light. More importantly, if the magnetization directions of the two electrodes are antiparallel, the photocurrents with different spins are spatially separated, appearing at different electrodes. This phenomenon provides a new way to simultaneously generate two spin currents.
基金supported by the National Natural Science Foundation of China (Nos. 50831002, 50971025, 11174031,51071022)Program for Changjiang Scholars and Innovative Research Team in University, Beijing Nova Program (No.2011031)+1 种基金Beijing Natural Science Foundation (No.2102032)the National Basic Research Program of China(No. 2012CB932702)
文摘The electronic structures of spinel MgAl 2 O 4 and MgOtunnel barrier materials were investigated using first-principles density functional theory calculations. Our results show that similar electronic structures are found for the MgAl 2 O 4 and MgO tunneling barriers. The calculated direct energy gaps at the Γ-point are about 5.10 eV for MgAl 2 O 4 and 4.81 eV for MgO, respectively. Because of the similar feature in band structures from Γ high-symmetry point to F point ( band), the coherent tunneling effect might be expected to appear in MgAl 2 O 4-based MTJs like in MgO-based MTJs. The small difference of the surface free energies of Fe (2.9 J m 2 ) and MgAl 2 O 4 (2.27 J m 2 ) on the {100} orientation, and the smaller lattice mismatch between MgAl 2 O 4 and ferromagnetic electrodes than that between MgO and ferromagnetic electrodes, the spinel MgAl 2 O 4 can substitute MgO to fabricate the coherent tunneling and chemically stable magnetic tunnel junction structures, which will be applied in the next generation read heads or spintronic devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12074158,12174166,and 12104197)。
文摘We investigated the angle-dependent spin wave spectra of permalloy ring arrays with the fixed outer diameter and various inner diameters by ferromagnetic resonance spectroscopy and micromagnetic simulation.When the field is obliquely applied to the ring,local resonance mode can be observed in different parts of the rings.And the resonance mode will change to perpendicular spin standing waves if the magnetic field is applied along the perpendicular direction.The simulation results demonstrated this evolution and implied more resonance modes that maybe exist.And the mathematical fitting results based on the Kittel equation further proved the existence of local resonance mode.
基金Project supported by the National Basic Research Program of China(Grant No.2014CB920902)the National Natural Science Foundation of China(Grant Nos.61306105 and 51572278)+1 种基金the Information Science and Technology(TNList)Cross-discipline Foundation from Tsinghua National Laboratory,Chinathe Fund from the State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054,China
文摘Due to the upcoming demands of next-generation electronic/magnetoelectronic devices with low-energy consumption,emerging correlated materials（such as superconductors,topological insulators and manganites） are one of the highly promising candidates for the applications.For the past decades,manganites have attracted great interest due to the colossal magnetoresistance effect,charge-spin-orbital ordering,and electronic phase separation.However,the incapable of deterministic control of those emerging low-dimensional spin structures at ambient condition restrict their possible applications.Therefore,the understanding and control of the dynamic behaviors of spin order parameters at nanoscale in manganites under external stimuli with low energy consumption,especially at room temperature is highly desired.In this review,we collected recent major progresses of nanoscale control of spin structures in manganites at low dimension,especially focusing on the control of their phase boundaries,domain walls as well as the topological spin structures（e.g.,skyrmions）.In addition,capacitor-based prototype spintronic devices are proposed by taking advantage of the above control methods in manganites.This capacitor-based structure may provide a new platform for the design of future spintronic devices with low-energy consumption.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12074158, 12174166, 12104197, and 12104124)the Natural Science Foundation of Hebei Province, China (Grant No. A2021201008)。
文摘As a microwave generator, spin transfer nano-oscillator(STNO) based on skyrmion promises to become one of the next-generation spintronic devices. However, there still exist a few limitations to the practical applications. In this paper, we propose a new STNO based on synthetic antiferromagnetic(SAF) skyrmion pair assisted by a perpendicular fixed magnetic field. It is found that the oscillation frequency of this kind of STNO can reach up to 5.0 GHz, and the multiple oscillation peak with higher frequency can be realized under a fixed out-of-plane magnetic field. Further investigation shows that the skyrmion stability is improved by bilayer antiferromagnetic coupling, which guarantees the stability process of skyrmion under higher spin-polarized current density. Our results provide the alternative possibilities for designing new skyrmionbased STNO to further improve the oscillation frequency, and realize the output of multiple frequency microwave signal.
基金supported by the National Natural Science Foundation of China(Nos.12074244 and 12374292)the National Key R&D Program of China(No.2021YFA1202902)the open research fund of Songshan Lake Materials Laboratory(No.2021SLABFK07).
文摘Graphene nanoribbons(GNRs)are narrow strips of graphene with widths ranging from a few nanometers to a few tens of nanometers.GNRs possess most of the excellent properties of graphene,while also exhibiting unique physical characteristics not found in graphene,such as an adjustable band gap and spin-polarized edge states.These properties make GNRs an appealing candidate for carbon-based electronics.In this review,we begin by introducing the edge geometry and electronic bands of GNRs.We then discuss various methods for fabricating GNRs and analyze the characteristics of each method.Subsequently,the performance of GNR field-effect transistor devices obtained from a few representative GNR fabrication methods is discussed and compared.We also investigate the use of GNRs as quantum dots and spintronic devices.Finally,the challenges and opportunities of GNRs as a quantum material for next-generation electronics and spintronics are explored and proposed.
文摘Spintronics exploits magnetic order parameters to encode binary information and utilizes spin-dependent transport for data processing[1].To date,most spintronic devices have been based on ferromagnetic materials,which offer straightforward information writing and reading through manipulation and detection of their magnetization.A prototypical device is the magnetic tunnel junction(MTJ),where non-volatile memory readout is achieved via the tunneling magnetoresistance(TMR)effect—distinct resistance states arising from parallel and antiparallel alignments of ferromagnetic electrodes.MTJs serve as the building blocks of magnetic random-access memories(MRAMs),which have already found commercial applications.
