Magnetic skyrmions are recognized as potential information carriers for building the next-generation spintronic memory and logic devices.Towards functional device applications,efficient electrical detection of skyrmio...Magnetic skyrmions are recognized as potential information carriers for building the next-generation spintronic memory and logic devices.Towards functional device applications,efficient electrical detection of skyrmions at room temperature is one of the most important prerequisites.展开更多
Magnetic skyrmions are two-dimensional localized topological spin-structures characterized by the skyrmion number that measures the number of times of spins wrapping the Bloch sphere. Skyrmions behave like particles u...Magnetic skyrmions are two-dimensional localized topological spin-structures characterized by the skyrmion number that measures the number of times of spins wrapping the Bloch sphere. Skyrmions behave like particles under an external stimulus and are promising information carriers. Skyrmions can exist as an isolated object as well as skyrmion condensates in crystal structures, helical/conical states, mazes or irregular stripy states with emergent electromagnetic fields. Thus,skyrmions provide a nice platform for studying fundamental physics, other than its applications in spintronics. In this perspective, we briefly review some recent progress in the field and present an outlook of the fundamental challenges in device applications.展开更多
Topological textures in optics such as skyrmions and merons are increasingly studied for their potential functions in light–matter interactions,deep-subwavelength imaging,and nanometrology.However,they were previousl...Topological textures in optics such as skyrmions and merons are increasingly studied for their potential functions in light–matter interactions,deep-subwavelength imaging,and nanometrology.However,they were previously generated either in strongly confined guided waves or in paraxial beams.This has posed a significant challenge in constructing skyrmions in nonparaxial propagating waves due to the lack of symmetry-breaking in the optical field and difficulty in characterizing the full three-dimensional spin textures at the nanoscale.We theoretically propose and experimentally demonstrate the generation of skyrmionic spin textures in nonparaxial light,where skyrmionic textures with a Bloch-type scheme,including isolated skyrmioniums,skyrmion,and meron lattices are generated in free space.We introduce the interplay between the Hertz potentials to break the dual symmetry of light and build well-defined domains of skyrmions.We experimentally realized the topological textures by applying a hybrid polarized optical vortex and observed the complete three-dimensional spin distributions by a dual-mode waveguide probe.By bridging the gap in the skyrmionic group,we present a topologic diagram,showing how spin–orbit coupling of light governs the spin topology.These findings offer new insights into optical quasiparticles and electron–photon correspondence,potentially facilitating advanced applications in optical metrology,sensing,and storage.展开更多
Chiral magnetic skyrmions are topological swirling spin textures that hold promise for future information technology. The electrical nucleation and motion of skyrmions have been experimentally demonstrated in the last...Chiral magnetic skyrmions are topological swirling spin textures that hold promise for future information technology. The electrical nucleation and motion of skyrmions have been experimentally demonstrated in the last decade, while electrical detection compatible with semiconductor processes has not been achieved, and this is considered one of the most crucial gaps regarding the use of skyrmions in real applications. Here, we report the direct observation of nanoscale skyrmions in Co Fe B/Mg O-based magnetic tunnel junction devices at room temperature. High-resolution magnetic force microscopy imaging and tunneling magnetoresistance measurements are used to illustrate the electrical detection of skyrmions,which are stabilized under the cooperation of interfacial Dzyaloshinskii–Moriya interaction, perpendicular magnetic anisotropy, and dipolar stray field. This skyrmionic magnetic tunnel junction shows a stable nonlinear multilevel resistance thanks to its topological nature and tunable density of skyrmions under current pulse excitation. These features provide important perspectives for spintronics to realize highdensity memory and neuromorphic computing.展开更多
MnSi in the B20 structure is a prototypical helimagnet that forms a skyrmion lattice, a vortex-like spin texture under applied magnetic field. We have systematically explored the synthesis of single crystal MnSi nanow...MnSi in the B20 structure is a prototypical helimagnet that forms a skyrmion lattice, a vortex-like spin texture under applied magnetic field. We have systematically explored the synthesis of single crystal MnSi nanowires via controlled oxide-assisted chemical vapor deposition and observed a characteristic signature of skyrmion magnetic ordering in the MnSi nanowires. The thickness of the SiO2 layer on the Si substrate plays the key role in obtaining a high yield of B20 MnSi skyrmion nanowires. A growth mechanism was proposed that is consistent with the existence of an optimum SiO2 thickness. A growth phase diagram was constructed based on the extensive studies of various growth conditions for various MnSi nanostructures. The persistence of both the helicoidal and skyrmion magnetic ordering in the one-dimensional wires was directly revealed by ac and dc magnetic measurements.展开更多
Dispersion characteristics of magnonic crystals have attracted considerable attention because of the potential applications for spin-wave devices.In this work,we investigated the strain-manipulated dispersion characte...Dispersion characteristics of magnonic crystals have attracted considerable attention because of the potential applications for spin-wave devices.In this work,we investigated the strain-manipulated dispersion characteristics of magnonic crystals with Dzyaloshinskii–Moriya interaction(DMI)and discussed the potential applications in spin-wave devices.Here,the ground states and stabilities of the magnonic crystals were investigated.Then,the strain-manipulated dispersion characteristics of the magnonic crystals based on domains and skyrmions were studied.The simulation results indicated that,the applied strain could manipulate the band widths and the positions of the allowed frequency bands.Finally,the realization of magnonic crystal heterojunctions and potential applications in spin-wave devices,such as filters,diodes,and transistors based on strain-manipulated magnonic crystals were proposed.Our research provides a theoretical foundation for designing tunable spin-wave devices based on strain-manipulated magnonic crystals with DMI.展开更多
We study the stability and dynamic behaviors of skyrmions in magnetic nanotubes,where curvature and cylindrical symmetry provide unique mechanisms for skyrmion formation and control.Unlike planar geometries,skyrmions ...We study the stability and dynamic behaviors of skyrmions in magnetic nanotubes,where curvature and cylindrical symmetry provide unique mechanisms for skyrmion formation and control.Unlike planar geometries,skyrmions confined in nanotubes exhibit elliptical shapes,stabilized through the interplay of curvature-induced effects,Dzyaloshinskii-Moriya interaction(DMI),and magnetic anisotropy.Using micromagnetic simulations,we construct phase diagrams of skyrmion stability as functions of DMI strength and anisotropy,identifying transitions to saturated or helical configurations in unstable regimes.The dynamics reveal distinct counterclockwise gyration modes,strongly influenced by tube geometry and applied microwave fields.We find that external magnetic fields significantly enhance the azimuthal velocity(v_(φ))while maintaining a consistent axial motion(v_(z))along the-z-direction.Furthermore,transitions between gyration and linear translation modes emerge,governed by the combined effects of magnetic field,DMI,and curvature.Notably,the skyrmion's motion direction depends on the excitation mode and DMI sign,while curvature-modified spin textures produce effective fields without conventional pinning.These results demonstrate that magnetic nanotubes offer a robust and tunable platform for skyrmion manipulation,with potential applications in next-generation memory and logic devices.Our findings also highlight the role of curvature in enabling stable and controllable topological spin textures for advanced spintronic technologies.展开更多
Spin waves,quantized as magnons,constitute a fundamental class of excitations and serve as one of the primary angular momentum carriers in magnetic systems.Devoid of Joule heating,a magnonic device that routes spin wa...Spin waves,quantized as magnons,constitute a fundamental class of excitations and serve as one of the primary angular momentum carriers in magnetic systems.Devoid of Joule heating,a magnonic device that routes spin waves between different ports holds promise for an energy-efficient information infrastructure.Here,we systematically investigate the transport behavior of a magnetic skyrmion-based magnon circulator,a representative device that directs spin wave flow in a non-reciprocal manner.Particularly,a ballistic transport model is established,where the scattering of spin waves by magnetic skyrmions is simplified as magnon deflection by fictitious electromagnetic fields within the skyrmions.Through the combination of ballistic analyses and micromagnetic simulations,the circulation performance is rigorously evaluated for multiple magnon circulators.展开更多
We theoretically demonstrate that multipartite entanglement and one-way Einstein-Podolsky-Rosen(EPR)steering in a magnon frequency comb(MFC)can be generated in a hybrid magnon-skyrmion system.When the system is driven...We theoretically demonstrate that multipartite entanglement and one-way Einstein-Podolsky-Rosen(EPR)steering in a magnon frequency comb(MFC)can be generated in a hybrid magnon-skyrmion system.When the system is driven by two microwave fields at the magnonic whispering gallery mode(m WGM)and the skyrmion,the skyrmion can be simultaneously entangled with three magnon modes of the MFC and the entanglement of the first-order magnon pair in the MFC also appears.The results show that the perfect one-way steering between the skyrmion and the three magnons can be obtained.Interestingly,the steering direction can be manipulated by controlling the amplitudes of two drive fields,which provides flexibility in controlling the asymmetry of the EPR steering and may well have practical applications.Moreover,the genuine tripartite entanglement among the skyrmion and the first-order magnon pair can be achieved with appropriate parameters in the steady state.Our work exhibits that the MFC has great potential in preparing multi-mode entanglement resources,with promising applications in quantum communication.展开更多
Understanding skyrmion–skyrmion interactions and their dynamical effects is crucial for skyrmion-based applications.In this article,we investigate the deformation of skyrmions induced by the inter-skyrmion interactio...Understanding skyrmion–skyrmion interactions and their dynamical effects is crucial for skyrmion-based applications.In this article,we investigate the deformation of skyrmions induced by the inter-skyrmion interaction in both static and dynamic scenarios for a two-skyrmion system.In the static case under a pinning magnetic field,the inter-skyrmion interaction energy decreases rapidly with increasing separation between the skyrmions,while their individual sizes grow.The semiaxis ratio of the elliptical skyrmion exhibits non-monotonic behavior,owing to the competition between skyrmion–skyrmion interactions and pinning effects.In dynamic simulations after removing the external pinning field,the two skyrmions spiral away from each other with increasing separation.Following a rapid relaxation period after magnetic field withdrawal,their semiaxis ratio typically increases with distance and the skyrmions gradually approach a perfect circular shape.These findings provide valuable insights into the behavior and interactions of two-skyrmion systems.展开更多
The new magnetic degree of freedom provided by the noncollinear structure plays an important role in the development of spintronic devices.In this work,we conducted a systematic study on the magnetic and electrical tr...The new magnetic degree of freedom provided by the noncollinear structure plays an important role in the development of spintronic devices.In this work,we conducted a systematic study on the magnetic and electrical transport properties of the hexagonal noncollinear ferromagnetic MnFeGe alloy.Abnormal Hall effect and moderate magnetoresistance(MR)were observed below the Curie temperature(~200 K)of MnFeGe,in both bulk and thin-film forms.Notably,the perpendicular MR in all samples firstly grows,then quasi-linearly descends with magnetic field increasing,making an irregular M-type MR in the low-field region.It is speculated that the abnormal MR is related to the magnetic domain change,and combined with micromagnetic simulations,the labyrinth domain and sparse bubble formation are verified to exist in MnFeGe.Our work offers an understanding of the lowfield-positive MR in a ferromagnet,as well as raises the possibility of magnetic bubble formation in this noncollinear system.展开更多
A magnetic skyrmion is a particle-like spin swirling object with a nontrivial topology that holds great promise for next-generation information carriers in highperformance spintronic devices.It was discovered in a chi...A magnetic skyrmion is a particle-like spin swirling object with a nontrivial topology that holds great promise for next-generation information carriers in highperformance spintronic devices.It was discovered in a chiral magnet,MnSi with B20 structure,in 2009 and later confirmed as a common feature of magnetic compounds with Dzyaloshinsky-Moriya interaction(DMI).In this work,we provide fundamental insight into the magnetic properties of skyrmion-hosting materials originating from DMI.The relationship between the point groups of the materials and DMI is introduced;then,the common features of magnetic skyrmions experimentally verified in the magnetization and magnetotransport measurements are highlighted.Finally,other particle-like magnetic configurations in chiral magnets and the crossover with a superconductor are discussed.展开更多
Voltage-controlled magnetic skyrmions have attracted special attention because they satisfy the requirements for well-controlled high-efficiency and energy saving for future skyrmion-based neuron device applications.I...Voltage-controlled magnetic skyrmions have attracted special attention because they satisfy the requirements for well-controlled high-efficiency and energy saving for future skyrmion-based neuron device applications.In this work,we propose a compact leaky-integrate-fire(LIF)spiking neuron device by using the voltage-driven skyrmion dynamics in a multiferroic nanodisk structure.The skyrmion dynamics is controlled by well tailoring voltage-induced piezostrains,where the skyrmion radius can be effectively modulated by applying the piezostrain pulses.Like the biological neuron,the proposed skyrmionic neuron will accumulate a membrane potential as skyrmion radius is varied by inputting the continuous piezostrain spikes,and the skyrmion radius will return to the initial state in the absence of piezostrain.Therefore,this skyrmion radius-based membrane potential will reach a definite threshold value by the strain stimuli and then reset by removing the stimuli.Such the LIF neuronal functionality and the behaviors of the proposed skyrmionic neuron device are elucidated through the micromagnetic simulation studies.Our results may benefit the utilization of skyrmionic neuron for constructing the future energy-efficient and voltage-tunable spiking neural networks.展开更多
Magnetic skyrmions,the topological spin textures firstly observed in chiral magnets,have aroused huge interest due to their emergent electromagnetism and potential applications in spintronics.Over the last decade,sign...Magnetic skyrmions,the topological spin textures firstly observed in chiral magnets,have aroused huge interest due to their emergent electromagnetism and potential applications in spintronics.Over the last decade,significant efforts have been devoted to skyrmion generation,stabilization,and dynamics.In most cases,the theoretical and experimental investigations have been performed in the materials where the skyrmions have a circular shape.As we know,magnetic anisotropy(K_(u))and Dzyaloshinskii-Moriya interaction(DMI)play key roles in the stabilization of the skyrmions in chiral magnets.Therefore,modifying the Kand DMI provide new degrees of freedom for studying the related physics and applications of skyrmions in addition to engineering their energetics and sizes.In this review,the latest progress on the study of the anisotropic deformation of magnetic skyrmions(i.e.,elliptical magnetic skyrmions)is summarized.The physical origins and important advantages of elliptical magnetic skyrmions are mainly focused on.This review gives an insight into the understanding of the physical mechanisms of elliptical magnetic skyrmion-hosting systems.展开更多
In curved geometries,a lot of novel curvaturedriven effects are discovered due to the curvature-induced effective anisotropy and Dzyaloshinskii-Moriya interaction.Curvature effect also provides means to modify convent...In curved geometries,a lot of novel curvaturedriven effects are discovered due to the curvature-induced effective anisotropy and Dzyaloshinskii-Moriya interaction.Curvature effect also provides means to modify conventional results and launch new functionalities in study of magnetic skyrmions.Magnetic skyrmions are particle-like spin textures with topological protections.It has been found in several magnetic materials and has been one of the research hotspots in magnetism and spintronics as the carriers of information.BothDzyaloshinskii-Moriya interaction and anisotropy have significant effects on the formation and stability of magnetic skyrmions.The magnetic skyrmions in curved geometries show some novel characteristics,and the study in this field may promote the development of magnetic skyrmions.This article provides a review of the present state of the research on skyrmions in curved geometries including curved nanotracks,thin films with curved defect,nanotubes,spherical and hemispherical shells.The reviewmainly covers three aspects,the formation and stability of skyrmions,the shape and size of skyrmions,and the dynamical behaviors of skyrmions in curved geometries.展开更多
Skyrmions are nano-scale quasi-particles with topological protection,which have potential applications in next-generation spintronics-based information storage.Numerous papers have been published to review various asp...Skyrmions are nano-scale quasi-particles with topological protection,which have potential applications in next-generation spintronics-based information storage.Numerous papers have been published to review various aspects of skyrmions,including physics,materials and applications.However,no review paper has focused on rare metals which play important roles in nucleating and manipulating skyrmions and other topological states.In this paper,various roles of rare metals have been classified and summarized,which can tune Curie temperature(TC),Dzyaloshinskii-Moriya interaction(DMI),magnetocrystalline anisotropy,Ruderman-Kittel-Kasuya-Yosida(RKKY)interaction and four-spin interaction so as to trigger the generation of skyrmions and other topological spin structures.The materials covered include typical B20 crystals,various layered systems with interfacial DMI,frustrated materials,antiferromagnets,ferrimagnets,twodimensional(2D)materials,etc.In addition,the rare-earth(RE)permanent magnets can provide an energy barrier and enrich the dynamic behaviors of skyrmions,which has also been reviewed.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFA1405100)the NSFC distinguished Young Scholar program(Grant No.12225409)+6 种基金the Basic Science Center Project of National Natural Science Foundation of China(NSFC)(Grant No.52388201)the NSFC general program(Grant Nos.52271181,51831005,and 12421004)the Innovation Program for Quantum Science and Technology(Grant No.2023ZD0300500)Beijing Natural Science Foundation(Grant No.Z240006)supported by the KAUST Office of Sponsored Research(OSR)under Award Nos.ORA-CRG102021-4665 and ORA-CRG11-2022-5031supported by the National Key Research and Development Program of China(No.2024YFA1408503)Sichuan Province Science and Technology Support Program(No.2025YFHZ0147)。
文摘Magnetic skyrmions are recognized as potential information carriers for building the next-generation spintronic memory and logic devices.Towards functional device applications,efficient electrical detection of skyrmions at room temperature is one of the most important prerequisites.
基金financial support from the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB33030100)the Equipment Development Project of Chinese Academy of Sciences (Grant No. YJKYYQ20180012)+1 种基金supported by the National Natural Science Foundation of China (Grant No. 11974296)Hong Kong RGC, China (Grant Nos. 16301518, 16301619, and 6302321)。
文摘Magnetic skyrmions are two-dimensional localized topological spin-structures characterized by the skyrmion number that measures the number of times of spins wrapping the Bloch sphere. Skyrmions behave like particles under an external stimulus and are promising information carriers. Skyrmions can exist as an isolated object as well as skyrmion condensates in crystal structures, helical/conical states, mazes or irregular stripy states with emergent electromagnetic fields. Thus,skyrmions provide a nice platform for studying fundamental physics, other than its applications in spintronics. In this perspective, we briefly review some recent progress in the field and present an outlook of the fundamental challenges in device applications.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030009)the National Natural Science Foundation of China(Grant Nos.62075139,12434012,92050202,and 12204309)+5 种基金the Science and Technology Innovation Commission of Shenzhen(Grant Nos.RCJC20200714114435063 and JCYJ20220531103403008)the Shanghai Rising-Star Program(Grant No.22YF1415200)the Natural Science Foundation of Guangdong Province(Grant No.2023A1515012670)the Innovation Team Project of Ordinary University of Guangdong Provincial Education Bureau(Grant No.2024KCXTD014)the Research Team Cultivation Program of Shenzhen University(Grant No.2023QNT012)the Shenzhen University 2035 Initiative(Grant No.2023B004)。
文摘Topological textures in optics such as skyrmions and merons are increasingly studied for their potential functions in light–matter interactions,deep-subwavelength imaging,and nanometrology.However,they were previously generated either in strongly confined guided waves or in paraxial beams.This has posed a significant challenge in constructing skyrmions in nonparaxial propagating waves due to the lack of symmetry-breaking in the optical field and difficulty in characterizing the full three-dimensional spin textures at the nanoscale.We theoretically propose and experimentally demonstrate the generation of skyrmionic spin textures in nonparaxial light,where skyrmionic textures with a Bloch-type scheme,including isolated skyrmioniums,skyrmion,and meron lattices are generated in free space.We introduce the interplay between the Hertz potentials to break the dual symmetry of light and build well-defined domains of skyrmions.We experimentally realized the topological textures by applying a hybrid polarized optical vortex and observed the complete three-dimensional spin distributions by a dual-mode waveguide probe.By bridging the gap in the skyrmionic group,we present a topologic diagram,showing how spin–orbit coupling of light governs the spin topology.These findings offer new insights into optical quasiparticles and electron–photon correspondence,potentially facilitating advanced applications in optical metrology,sensing,and storage.
基金financial support from the National Key R&D Program of China(2018YFB0407602,and 2020YFA0309300)National Natural Science Foundation of China(61627813,61871008,62001019,12004024,and 51901081)+5 种基金Beijing Natural Science Foundation(4202043)Beijing Nova Program from Beijing Municipal Science and Technology Commission(Z201100006820042)National Natural Science Foundation of China-German Research Foundation(52061135105)Outstanding Research Project of Shen Yuan Honors College,BUAA(230121102)the Science and Technology Program of Guangzhou(202002030052)Joint Research Key Fund for Guangzhou and Shen Zhen(2021B1515120047)。
文摘Chiral magnetic skyrmions are topological swirling spin textures that hold promise for future information technology. The electrical nucleation and motion of skyrmions have been experimentally demonstrated in the last decade, while electrical detection compatible with semiconductor processes has not been achieved, and this is considered one of the most crucial gaps regarding the use of skyrmions in real applications. Here, we report the direct observation of nanoscale skyrmions in Co Fe B/Mg O-based magnetic tunnel junction devices at room temperature. High-resolution magnetic force microscopy imaging and tunneling magnetoresistance measurements are used to illustrate the electrical detection of skyrmions,which are stabilized under the cooperation of interfacial Dzyaloshinskii–Moriya interaction, perpendicular magnetic anisotropy, and dipolar stray field. This skyrmionic magnetic tunnel junction shows a stable nonlinear multilevel resistance thanks to its topological nature and tunable density of skyrmions under current pulse excitation. These features provide important perspectives for spintronics to realize highdensity memory and neuromorphic computing.
文摘MnSi in the B20 structure is a prototypical helimagnet that forms a skyrmion lattice, a vortex-like spin texture under applied magnetic field. We have systematically explored the synthesis of single crystal MnSi nanowires via controlled oxide-assisted chemical vapor deposition and observed a characteristic signature of skyrmion magnetic ordering in the MnSi nanowires. The thickness of the SiO2 layer on the Si substrate plays the key role in obtaining a high yield of B20 MnSi skyrmion nanowires. A growth mechanism was proposed that is consistent with the existence of an optimum SiO2 thickness. A growth phase diagram was constructed based on the extensive studies of various growth conditions for various MnSi nanostructures. The persistence of both the helicoidal and skyrmion magnetic ordering in the one-dimensional wires was directly revealed by ac and dc magnetic measurements.
文摘Dispersion characteristics of magnonic crystals have attracted considerable attention because of the potential applications for spin-wave devices.In this work,we investigated the strain-manipulated dispersion characteristics of magnonic crystals with Dzyaloshinskii–Moriya interaction(DMI)and discussed the potential applications in spin-wave devices.Here,the ground states and stabilities of the magnonic crystals were investigated.Then,the strain-manipulated dispersion characteristics of the magnonic crystals based on domains and skyrmions were studied.The simulation results indicated that,the applied strain could manipulate the band widths and the positions of the allowed frequency bands.Finally,the realization of magnonic crystal heterojunctions and potential applications in spin-wave devices,such as filters,diodes,and transistors based on strain-manipulated magnonic crystals were proposed.Our research provides a theoretical foundation for designing tunable spin-wave devices based on strain-manipulated magnonic crystals with DMI.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1405900)the National Natural Science Foundation of China(Grant Nos.U2441217 and 12074058)Sichuan Science and Technology Program(Grant No.2024YFHZ0372)。
文摘We study the stability and dynamic behaviors of skyrmions in magnetic nanotubes,where curvature and cylindrical symmetry provide unique mechanisms for skyrmion formation and control.Unlike planar geometries,skyrmions confined in nanotubes exhibit elliptical shapes,stabilized through the interplay of curvature-induced effects,Dzyaloshinskii-Moriya interaction(DMI),and magnetic anisotropy.Using micromagnetic simulations,we construct phase diagrams of skyrmion stability as functions of DMI strength and anisotropy,identifying transitions to saturated or helical configurations in unstable regimes.The dynamics reveal distinct counterclockwise gyration modes,strongly influenced by tube geometry and applied microwave fields.We find that external magnetic fields significantly enhance the azimuthal velocity(v_(φ))while maintaining a consistent axial motion(v_(z))along the-z-direction.Furthermore,transitions between gyration and linear translation modes emerge,governed by the combined effects of magnetic field,DMI,and curvature.Notably,the skyrmion's motion direction depends on the excitation mode and DMI sign,while curvature-modified spin textures produce effective fields without conventional pinning.These results demonstrate that magnetic nanotubes offer a robust and tunable platform for skyrmion manipulation,with potential applications in next-generation memory and logic devices.Our findings also highlight the role of curvature in enabling stable and controllable topological spin textures for advanced spintronic technologies.
基金supported by the National Natural Science Foundation of China(Grant Nos.12374117 and 11904260)the Natural Science Foundation of Tianjin(Grant No.20JCQNJC02020)。
文摘Spin waves,quantized as magnons,constitute a fundamental class of excitations and serve as one of the primary angular momentum carriers in magnetic systems.Devoid of Joule heating,a magnonic device that routes spin waves between different ports holds promise for an energy-efficient information infrastructure.Here,we systematically investigate the transport behavior of a magnetic skyrmion-based magnon circulator,a representative device that directs spin wave flow in a non-reciprocal manner.Particularly,a ballistic transport model is established,where the scattering of spin waves by magnetic skyrmions is simplified as magnon deflection by fictitious electromagnetic fields within the skyrmions.Through the combination of ballistic analyses and micromagnetic simulations,the circulation performance is rigorously evaluated for multiple magnon circulators.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1402802)the National Natural Science Foundation of China(Grant Nos.12374103,12434003,and 12074057)。
文摘We theoretically demonstrate that multipartite entanglement and one-way Einstein-Podolsky-Rosen(EPR)steering in a magnon frequency comb(MFC)can be generated in a hybrid magnon-skyrmion system.When the system is driven by two microwave fields at the magnonic whispering gallery mode(m WGM)and the skyrmion,the skyrmion can be simultaneously entangled with three magnon modes of the MFC and the entanglement of the first-order magnon pair in the MFC also appears.The results show that the perfect one-way steering between the skyrmion and the three magnons can be obtained.Interestingly,the steering direction can be manipulated by controlling the amplitudes of two drive fields,which provides flexibility in controlling the asymmetry of the EPR steering and may well have practical applications.Moreover,the genuine tripartite entanglement among the skyrmion and the first-order magnon pair can be achieved with appropriate parameters in the steady state.Our work exhibits that the MFC has great potential in preparing multi-mode entanglement resources,with promising applications in quantum communication.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12175180,11934015,and12247103,Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant Nos.22JSZ005 and22JSQ041)the Natural Science Basic Research Program of Shaanxi Province,China(Grant No.2024JC-YBMS-022)。
文摘Understanding skyrmion–skyrmion interactions and their dynamical effects is crucial for skyrmion-based applications.In this article,we investigate the deformation of skyrmions induced by the inter-skyrmion interaction in both static and dynamic scenarios for a two-skyrmion system.In the static case under a pinning magnetic field,the inter-skyrmion interaction energy decreases rapidly with increasing separation between the skyrmions,while their individual sizes grow.The semiaxis ratio of the elliptical skyrmion exhibits non-monotonic behavior,owing to the competition between skyrmion–skyrmion interactions and pinning effects.In dynamic simulations after removing the external pinning field,the two skyrmions spiral away from each other with increasing separation.Following a rapid relaxation period after magnetic field withdrawal,their semiaxis ratio typically increases with distance and the skyrmions gradually approach a perfect circular shape.These findings provide valuable insights into the behavior and interactions of two-skyrmion systems.
基金financially supported by the National Natural Science Foundation of China (Nos.11604148 and 51771003)
文摘The new magnetic degree of freedom provided by the noncollinear structure plays an important role in the development of spintronic devices.In this work,we conducted a systematic study on the magnetic and electrical transport properties of the hexagonal noncollinear ferromagnetic MnFeGe alloy.Abnormal Hall effect and moderate magnetoresistance(MR)were observed below the Curie temperature(~200 K)of MnFeGe,in both bulk and thin-film forms.Notably,the perpendicular MR in all samples firstly grows,then quasi-linearly descends with magnetic field increasing,making an irregular M-type MR in the low-field region.It is speculated that the abnormal MR is related to the magnetic domain change,and combined with micromagnetic simulations,the labyrinth domain and sparse bubble formation are verified to exist in MnFeGe.Our work offers an understanding of the lowfield-positive MR in a ferromagnet,as well as raises the possibility of magnetic bubble formation in this noncollinear system.
基金financially supported by the Key Research Program of Frontier Sciences,CAS(No.QYZDBSSW-SLH009)the Key Research Program of the Chinese Academy of Sciences(No.KJZD-SW-M01)+4 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB33030100)the Equipment Development Project of Chinese Academy of Sciences(No.YJKYYQ20180012)the Natural Science Foundation of China(No.11904368)the Natural Science Foundation of Anhui Province(No.2008085QA32)supported by the High Magnetic Field Laboratory of Anhui Province。
文摘A magnetic skyrmion is a particle-like spin swirling object with a nontrivial topology that holds great promise for next-generation information carriers in highperformance spintronic devices.It was discovered in a chiral magnet,MnSi with B20 structure,in 2009 and later confirmed as a common feature of magnetic compounds with Dzyaloshinsky-Moriya interaction(DMI).In this work,we provide fundamental insight into the magnetic properties of skyrmion-hosting materials originating from DMI.The relationship between the point groups of the materials and DMI is introduced;then,the common features of magnetic skyrmions experimentally verified in the magnetization and magnetotransport measurements are highlighted.Finally,other particle-like magnetic configurations in chiral magnets and the crossover with a superconductor are discussed.
基金the National Natural Science Foundation of China(Grant Nos.11902316,51902300,and 11972333)the Natural Science Foundation of Zhejiang Province,China(Grant Nos.LQ19F010005,LY21F010011,and LZ19A020001).
文摘Voltage-controlled magnetic skyrmions have attracted special attention because they satisfy the requirements for well-controlled high-efficiency and energy saving for future skyrmion-based neuron device applications.In this work,we propose a compact leaky-integrate-fire(LIF)spiking neuron device by using the voltage-driven skyrmion dynamics in a multiferroic nanodisk structure.The skyrmion dynamics is controlled by well tailoring voltage-induced piezostrains,where the skyrmion radius can be effectively modulated by applying the piezostrain pulses.Like the biological neuron,the proposed skyrmionic neuron will accumulate a membrane potential as skyrmion radius is varied by inputting the continuous piezostrain spikes,and the skyrmion radius will return to the initial state in the absence of piezostrain.Therefore,this skyrmion radius-based membrane potential will reach a definite threshold value by the strain stimuli and then reset by removing the stimuli.Such the LIF neuronal functionality and the behaviors of the proposed skyrmionic neuron device are elucidated through the micromagnetic simulation studies.Our results may benefit the utilization of skyrmionic neuron for constructing the future energy-efficient and voltage-tunable spiking neural networks.
基金financially supported by Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110553)Science Center of the National Science Foundation of China(No.52088101)+5 种基金Beijing Natural Science Foundation(No.Z190009)the National Natural Science Foundation of China(NSFC,Nos.11874409 and 11904056)K.C.Wong Education Foundation(No.GJTD-2019-14)China Postdoctoral Science Foundation(No.2020M670499)Guangzhou basic and applied basic research project(No.202102020053)the startup funding from Songshan Lake Materials Laboratory(No.Y1D1071S511)。
文摘Magnetic skyrmions,the topological spin textures firstly observed in chiral magnets,have aroused huge interest due to their emergent electromagnetism and potential applications in spintronics.Over the last decade,significant efforts have been devoted to skyrmion generation,stabilization,and dynamics.In most cases,the theoretical and experimental investigations have been performed in the materials where the skyrmions have a circular shape.As we know,magnetic anisotropy(K_(u))and Dzyaloshinskii-Moriya interaction(DMI)play key roles in the stabilization of the skyrmions in chiral magnets.Therefore,modifying the Kand DMI provide new degrees of freedom for studying the related physics and applications of skyrmions in addition to engineering their energetics and sizes.In this review,the latest progress on the study of the anisotropic deformation of magnetic skyrmions(i.e.,elliptical magnetic skyrmions)is summarized.The physical origins and important advantages of elliptical magnetic skyrmions are mainly focused on.This review gives an insight into the understanding of the physical mechanisms of elliptical magnetic skyrmion-hosting systems.
基金financially supported by the National Natural Science Foundation of China (No. 11774045)Liaoning Revitalization Talents Program (No. XLYC2007150)
文摘In curved geometries,a lot of novel curvaturedriven effects are discovered due to the curvature-induced effective anisotropy and Dzyaloshinskii-Moriya interaction.Curvature effect also provides means to modify conventional results and launch new functionalities in study of magnetic skyrmions.Magnetic skyrmions are particle-like spin textures with topological protections.It has been found in several magnetic materials and has been one of the research hotspots in magnetism and spintronics as the carriers of information.BothDzyaloshinskii-Moriya interaction and anisotropy have significant effects on the formation and stability of magnetic skyrmions.The magnetic skyrmions in curved geometries show some novel characteristics,and the study in this field may promote the development of magnetic skyrmions.This article provides a review of the present state of the research on skyrmions in curved geometries including curved nanotracks,thin films with curved defect,nanotubes,spherical and hemispherical shells.The reviewmainly covers three aspects,the formation and stability of skyrmions,the shape and size of skyrmions,and the dynamical behaviors of skyrmions in curved geometries.
基金financially supported by the National Natural Science Foundation of China (Nos. 51771127, 52171188 52111530143, 12104327, 51901081, 11974298 and 61961136006)the National Key Research and Development Program of China (No. 2020YFA0309300)+6 种基金Sichuan Science and Technology Program (Application No. 21ZYZYTS0077)the Science and Technology Program of Guangzhou (No. 202002030052)Guangdong Special Support Project (No. 2019BT02X030)Shenzhen Fundamental Research Fund (No. JCYJ20210324120213037)Shenzhen Peacock Group Plan (No. KQTD20180413181702403)Pearl River Recruitment Program of Talents (No. 2017GC010293)the Grants-in-Aid for Scientific Research from JSPS KAKENHI (Nos. JP20F20363, JP21H01364 and JP21K18872)
文摘Skyrmions are nano-scale quasi-particles with topological protection,which have potential applications in next-generation spintronics-based information storage.Numerous papers have been published to review various aspects of skyrmions,including physics,materials and applications.However,no review paper has focused on rare metals which play important roles in nucleating and manipulating skyrmions and other topological states.In this paper,various roles of rare metals have been classified and summarized,which can tune Curie temperature(TC),Dzyaloshinskii-Moriya interaction(DMI),magnetocrystalline anisotropy,Ruderman-Kittel-Kasuya-Yosida(RKKY)interaction and four-spin interaction so as to trigger the generation of skyrmions and other topological spin structures.The materials covered include typical B20 crystals,various layered systems with interfacial DMI,frustrated materials,antiferromagnets,ferrimagnets,twodimensional(2D)materials,etc.In addition,the rare-earth(RE)permanent magnets can provide an energy barrier and enrich the dynamic behaviors of skyrmions,which has also been reviewed.
