In physics,our expectations for system behavior are often guided by intuitive arithmetic.For systems composed of identical units,we anticipate synergy of the contributions from these units,where 1+1=2.Conversely,for s...In physics,our expectations for system behavior are often guided by intuitive arithmetic.For systems composed of identical units,we anticipate synergy of the contributions from these units,where 1+1=2.Conversely,for systems built from opposing units,we expect cancellation of their contributions,where 1-1=0.This intuitive arithmetic has long underpinned our understanding of physical properties of materials,from electronic transport to optical responses.However,scientific breakthroughs often occur when nature reveals ways to circumvent these seemingly fundamental rules,opening new possibilities that challenge our deepest assumptions about material behavior.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 report the bifurcation of bound states in the continuum(BICs) in a dissipative cavity magnonic system, where a BIC splits into a pair of BICs. We theoretically analyze BICs in a dissipative cavity magnonic system a...We report the bifurcation of bound states in the continuum(BICs) in a dissipative cavity magnonic system, where a BIC splits into a pair of BICs. We theoretically analyze BICs in a dissipative cavity magnonic system and derive the critical condition for BICs bifurcation. Based on the theoretical results, we experimentally tune the dissipative photon–magnon coupling strength and demonstrate precise control over the detuning and number of BICs. When the dissipative coupling strength reaches a critical value, we observe the bifurcation of BICs, which is consistent with the theoretical prediction. Our systematic investigation of the evolution of BICs concerning the dissipative coupling strength and the discovery of the BIC bifurcation may enhance the sensitivity of BICs to external perturbations, potentially enabling applications in ultrasensitive detection.展开更多
A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise...A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise. Like many low phase noise oscillators, a cavity magnonic oscillator faces the challenge that its narrow resonance profile is not well suited for injection locking amplification. This work presents an improved design for such an oscillator configured as an injection locking amplifier(ILA) with an extended lock range. The proposed design features a two-stage architecture, consisting of a pre-amplification oscillator and a cavity magnonic oscillator, separated by an isolator to prevent backward locking.By optimizing the circuit parameters of each stage, the proposed design achieved an order of magnitude increase in lock range, when compared to its predecessors, all while preserving the phase noise quality of the input, making it well-suited for narrowband, sensitive signal amplification. Furthermore, this work provides a method for using oscillators with high spectral purity as injection locking amplifiers.展开更多
We investigate magnonic topology in the breathing Su–Schrieffer–Heeger(SSH) model, incorporating non-Hermitian effects. Our results demonstrate the coexistence of first-and second-order magnonic topologies, with non...We investigate magnonic topology in the breathing Su–Schrieffer–Heeger(SSH) model, incorporating non-Hermitian effects. Our results demonstrate the coexistence of first-and second-order magnonic topologies, with non-Hermitian effects exhibiting size-dependent behavior. In two-dimensional systems, non-Hermitian terms induce a flat band and gap closure along high-symmetry paths, whereas in one-dimensional systems, a finite band gap persists for small system sizes. Additionally, the corner states remain robust, and a pronounced non-Hermitian skin effect emerges. Our findings provide new insights into magnon-based devices, emphasizing the impact of non-Hermitian effects on their design and functionality.展开更多
Using the plane-wave expansion method, the spin-wave band structures of two-dimensional magnonic crystals consisting of square arrays of different shape scatterers are calculated numerically, and the effects of rotati...Using the plane-wave expansion method, the spin-wave band structures of two-dimensional magnonic crystals consisting of square arrays of different shape scatterers are calculated numerically, and the effects of rotating rectangle and hexagon scaterers on the gaps are studied, respectively. The results show that the gaps can be substantially opened and tuned by rotating the scatterers. This approach should be helpful in designing magnonic crystals with desired gaps.展开更多
We theoretically investigate the propagation characteristics of spin waves in skyrmion-based magnonic crystals. It is found that the dispersion relation can be manipulated by strains through magneto-elastic coupling. ...We theoretically investigate the propagation characteristics of spin waves in skyrmion-based magnonic crystals. It is found that the dispersion relation can be manipulated by strains through magneto-elastic coupling. Especially, the allowed bands and forbidden bands in dispersion relations shift to higher frequency with strain changing from compressive to tensile,while shifting to lower frequency with strain changing from tensile to compressive. We also confirm that the spin wave with specific frequency can pass the magnonic crystal or be blocked by tuning the strains. The result provides an advanced platform for studying the tunable skyrmion-based spin wave devices.展开更多
In this review,the recent developments in microelectronics,spintronics,and magnonics have been summarized and compared.Firstly,the history of the spintronics has been briefly reviewed.Moreover,the recent development o...In this review,the recent developments in microelectronics,spintronics,and magnonics have been summarized and compared.Firstly,the history of the spintronics has been briefly reviewed.Moreover,the recent development of magnonics such as magnon-mediated current drag effect(MCDE),magnon valve effect(MVE),magnon junction effect(MJE),magnon blocking effect(MBE),magnon-mediated nonlocal spin Hall magnetoresistance(MNSMR),magnon-transfer torque(MTT)effect,and magnon resonant tunneling(MRT)effect,magnon skin effect(MSE),etc.,existing in magnon junctions or magnon heterojunctions,have been summarized and their potential applications in memory and logic devices,etc.,are prospected,from which we can see a promising future for spintronics and magnonics beyond micro-electronics.展开更多
When there is a certain amount of field inhomogeneity,the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic(HMS)mode in addition to the uniform-precession Kittel mode.In cavity magnonics,we show ...When there is a certain amount of field inhomogeneity,the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic(HMS)mode in addition to the uniform-precession Kittel mode.In cavity magnonics,we show the nonlinearity and heating-induced frequency shifts of the Kittel mode and HMS mode in a yttrium-iron-garnet(YIG)sphere.When the Kittel mode is driven to generate a certain number of excitations,the temperature of the whole YIG sample rises and the HMS mode can display an induced frequency shift,and vice versa.This cross effect provides a new method to study the magnetization dynamics and paves a way for novel cavity magnonic devices by including the heating effect as an operational degree of freedom.展开更多
Many studies of magnon–photon coupling are performed in the frequency domain for microwave photons.In this work,we present analytical results of eigenfrequency,eigenstates,and temporal dynamics for the coupling betwe...Many studies of magnon–photon coupling are performed in the frequency domain for microwave photons.In this work,we present analytical results of eigenfrequency,eigenstates,and temporal dynamics for the coupling between ferromagnetic magnon and visible photon.In contrast to microwave photons,optical photons can be coupled with magnon in a dispersive interaction which produces both level repulsion and attraction by varying the magnon–photon frequency detuning.At resonance,the hybridized states are of linear polarization and circular polarization for level repulsion and level attraction respectively.As the detuning increases,the polarizations of level repulsion remain linear but those of level attraction vary from elliptical to linear polarizations.The temporal dynamics of level repulsion presents the beat-like behavior.The level attraction presents monotonous decay in the weak coupling regime but gives rise to instability in the strong coupling regime due to the magnon amplification.As the detuning is large,both magnon and photon amplitudes present a synchronizing oscillation.Our results are important for exploring the temporal evolution of magnon–photon coupling in the range of optical frequency and designing magnon-based timing devices.展开更多
The pseudospectral Landau-Lifshitz(PS-LL)model can describe atomic-scale magnetic exchange interactions within a continuum framework.This is achieved by employing a convolution kernel that models the nonlocal interact...The pseudospectral Landau-Lifshitz(PS-LL)model can describe atomic-scale magnetic exchange interactions within a continuum framework.This is achieved by employing a convolution kernel that models the nonlocal interaction in a grid-independent manner.Even though the PS-LL was originally introduced to address atomic exchange,any nonlocal kernel can be modeled.In the field of magnonics,the dipole field is fundamental to describe the dispersion relation of magnons,the quasiparticle representation of angular momentum.Because dipole-dipole interactions are longrange,numerical approaches typically rely on convolutions.Here,we demonstrate that the PS-LL model can be used to perform magnonic simulations with a single convolution kernel derived from analytical solutions.Wedemonstrate a twofold increase in computational speed compared with the full dipole calculation.This approach is valid insofar as the excitations are linear,which is typically the case for magnons.Our results have the potential to accelerate magnonic research,particularly for the inverse design method,where several simulations must be performed to achieve the desired outcome.展开更多
We develop a theory for the magnon Kerr effect in a cavity magnonics system, consisting of magnons in a small yttrium iron garnet(YIG) sphere strongly coupled to cavity photons, and use it to study the bistability in ...We develop a theory for the magnon Kerr effect in a cavity magnonics system, consisting of magnons in a small yttrium iron garnet(YIG) sphere strongly coupled to cavity photons, and use it to study the bistability in this hybrid system. To have a complete picture of the bistability phenomenon, we analyze two different cases in driving the cavity magnonics system, i.e.,directly pumping the YIG sphere and the cavity, respectively. In both cases, the magnon frequency shifts due to the Kerr effect exhibit a similar bistable behavior but the corresponding critical powers are different. Moreover, we show how the bistability of the system can be demonstrated using the transmission spectrum of the cavity. Our results are valid in a wide parameter regime and generalize the theory of bistability in a cavity magnonics system.展开更多
Recently,the photon–magnon coherent interaction based on the collective spins excitation in ferromagnetic materials has been achieved experimentally.Under the prospect,the magnons are proposed to store and process qu...Recently,the photon–magnon coherent interaction based on the collective spins excitation in ferromagnetic materials has been achieved experimentally.Under the prospect,the magnons are proposed to store and process quantum information.Meanwhile,cavity-optomagnonics which describes the interaction between photons and magnons has been developing rapidly as an interesting topic of the cavity quantum electrodynamics.Here in this short review,we mainly introduce the recent theoretical and experimental progress in the field of optomagnetic coupling and optical manipulation based on cavity-optomagnonics.According to the frequency range of the electromagnetic field,cavity optomagnonics can be divided into microwave cavity optomagnonics and optical cavity optomagnonics,due to the different dynamics of the photon–magnon interaction.As the interaction between the electromagnetic field and the magnetic materials is enhanced in the cavity-optomagnonic system,it provides great significance to explore the nonlinear characteristics and quantum properties for different magnetic systems.More importantly,the electromagnetic response of optomagnonics covers the frequency range from gigahertz to terahertz which provides a broad frequency platform for the multi-mode controlling in quantum systems.展开更多
A magnonic counterpart to optical frequency combs is vital for high-precision magnonic frequency metrology and spectroscopy.Here,we present an efficient mechanism for the generation of robust magnonic frequency combs ...A magnonic counterpart to optical frequency combs is vital for high-precision magnonic frequency metrology and spectroscopy.Here,we present an efficient mechanism for the generation of robust magnonic frequency combs in a yttrium iron garnet(YIG)sphere via magnetostrictive effects.We show that magnonic and vibrational dynamics in the ferrimagnetic sphere can be substantively modified in the presence of magnetostrictive effects,which results in degenerate and non-degenerate magnonic four-wave mixing and frequency conversion.Particularly,resonantly enhanced magnetostrictive effects can induce phonon laser action above a threshold,which leads to significant magnonic nonlinearity and enables a potentially practical scheme for the generation of robust magnonic frequency combs.Numerical calculations of both magnonic and phononic dynamics show excellent agreement with this theory.These results deepen our understanding of magnetostrictive interaction,open a novel and efficient pathway to realize magnonic frequency conversion and mixing in a magnonic device,and provide a sensitive tool for precision measurement.展开更多
Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling ...Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling the automatic derivation of analytical expressions for the eigenmatrix elements via symbolic computation,eliminating the need for tedious manual calculations.Using this approach,we investigate the impact of magnetic hysteresis on magnon-magnon coupling in a system with interlayer Dzyaloshinskii-Moriya interaction(DMI).The magnetic hysteresis leads to an asymmetric magnetic field dependence of the resonance frequency and alters the number of degeneracy points between the pure optical and acoustic modes.Moreover,it can result in the coupling strength at the gap of the f–H phase diagram being nearly vanishing,contrary to the conventionally expected maximum.These results deepen the understanding of the effect of interlayer DMI on magnon–magnon coupling and the proposed universal method significantly streamlines the solving process of magnon–magnon coupling problems.展开更多
The field of magnonics,which aims at using spin waves as carriers in data-processing devices,has attracted increasing interest in recent years.We present and study micromagnetically a nonlinear nanoscale magnonic ring...The field of magnonics,which aims at using spin waves as carriers in data-processing devices,has attracted increasing interest in recent years.We present and study micromagnetically a nonlinear nanoscale magnonic ring resonator device for enabling implementations of magnonic logic gates and neuromorphic magnonic circuits.In the linear regime,this device efficiently suppresses spin-wave transmission using the phenomenon of critical resonant coupling,thus exhibiting the behavior of a notch filter.By increasing the spin-wave input power,the resonance frequency is shifted,leading to transmission curves,depending on the frequency,reminiscent of the activation functions of neurons,or showing the characteristics of a power limiter.An analytical theory is developed to describe the transmission curve of magnonic ring resonators in the linear and nonlinear regimes,and is validated by a comprehensive micromagnetic study.The proposed magnonic ring resonator provides a multi-functional nonlinear building block for unconventional magnonic circuits.展开更多
Strong coupling effects in magnonic systems are highly promising.They combine the advantages of different quasiparticles and enable energy transfer for coherent information processing.When driven by microwave,electric...Strong coupling effects in magnonic systems are highly promising.They combine the advantages of different quasiparticles and enable energy transfer for coherent information processing.When driven by microwave,electric,or optical pumps,these coupling effects can give rise to intriguing nonlinear phenomena,which have become a focal point in the field of magnonics.This review systematically explores pump-engineered magnon-coupling systems from three perspectives:(1)pump-induced hybridization of magnon modes,(2)nonlinear manipulation of magnon dynamics,and(3)implementation of functional magnonic devices.Unlike conventional cavity-magnon interactions that are constrained by electromagnetic boundaries,pumped coupled magnons are liberated from these restrictions.They can operate over a broad frequency band rather than being confined to discrete modes.An example is the recently discovered pump-induced magnon mode(PIM).These magnons arise from the collective excitations of unsaturated spins driven by microwave pumps.They exhibit reduced damping and photon-number-sensitive splitting characteristics,facilitating waveform-controlled coupling strength and enhanced nonlinearity—features that support phenomena such as magnonic frequency combs(MFCs).By expanding this principle to electric pumping schemes,we bridge fundamental physics and practical device applications,enabling nonreciprocal switching and meter-scale strong coupling.These advances establish high-dimensional control capabilities for coupled magnonics and pave the way for their use as a promising platform for dynamically programmable devices,magnetic-field sensing,and coherent networks.展开更多
Spin waves in van der Waals magnets hold promise for magnonic devices and circuits down to the two-dimensional limit.However,their short decay lengths pose challenges for practical applications.Here,we report on a mat...Spin waves in van der Waals magnets hold promise for magnonic devices and circuits down to the two-dimensional limit.However,their short decay lengths pose challenges for practical applications.Here,we report on a material platform consisting of a van der Waals magnet,Fe_(5)GeTe_(2)(FGT),and a ferrimagnetic insulator of yttrium iron garnet,Y_(3)Fe_(5)O_(12)(YIG),which supports the low-loss propagation of spin waves.Using broadband spin-wave spectroscopy,we observed an increase in spin-wave group velocity with decreasing temperature,which peaks at 30 K in the YIG and FGT/YIG films.This effect is ascribed to a change in the saturation magnetization of YIG and FGT/YIG at low temperature,resulting in a change in the spin-wave dispersion relations.Using micromagnetic simulations,we further investigated spin-wave propagation in an FGT/YIG bilayer and revealed a longer spin-wave decay length in the bilayer than in a single FGT layer,which is due to the lower effective damping in the bilayer.Moreover,asymmetric spin-wave dispersion,induced by a chiral dipolar interaction between the YIG and FGT layers,enables nonreciprocal control of spin-wave propagation.展开更多
Altermagnets,a new type of collinear antiferromagnet,exhibiting non-degenerate electron and magnon dispersion in momentum space have attracted intensive research attention.We theoretically analyze the origin and featu...Altermagnets,a new type of collinear antiferromagnet,exhibiting non-degenerate electron and magnon dispersion in momentum space have attracted intensive research attention.We theoretically analyze the origin and feature of chiral magnon splitting in representative altermagnets including tetragonal RuO_(2),hexagonal MnTe,and orthorhombic LaMnO_(3).The magnon spin transport properties including spin Seebeck and spin Nernst coefcients have been investigated.Through these materials,we demonstrate the diference of chiral splitting in d-wave and g-wave antiferromagnet on magnon transport.RuO2with planar magnon splitting exhibits signifcant magnon spin Nernst and magnon spin Seebeck anisotropy in(110)and(001)planes,whereas MnTe,due to its bulk-like magnon splitting,is incapable of producing magnon spin Nernst efect.Our work may provide in-depth understanding on the mechanisms of nonrelativistic magnon splitting and thermal spin transport in altermagnets.展开更多
Magnon spin currents in insulating magnets are useful for low-power spintronics. However, in magnets stacked by antiferromagnetic(AFM) exchange coupling, which have recently aroused significant interest for potential ...Magnon spin currents in insulating magnets are useful for low-power spintronics. However, in magnets stacked by antiferromagnetic(AFM) exchange coupling, which have recently aroused significant interest for potential applications in spintronics, Bose–Einstein distribution populates magnon states across all energies from opposite eigenmodes, and hence the magnon spin current is largely compensated. Contrary to this common observation,here, we show that magnets with X-type AFM stacking, where opposite magnetic sublattices form orthogonal intersecting chains, support giant magnon spin currents with minimal compensation. Our model Hamiltonian calculations predict magnetic chain locking of magnon spin currents in these X-type magnets, significantly reducing their compensation ratio. In addition, the one-dimensional nature of the chain-like magnetic sublattices enhances magnon spin conductivities surpassing those of two-dimensional ferromagnets and canonical altermagnets. Notably, uncompensated X-type magnets, such as odd-layer antiferromagnets and ferrimagnets, can exhibit magnon spin currents polarized opposite to those expected by their net magnetization. These unprecedented properties of X-type magnets, combined with their inherent advantages resulting from AFM coupling, offer a promising new path for low-power high-performance spintronics.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.12374109)the National Key Research and Development Program of China (Grant No.2023YFA1406600)。
文摘In physics,our expectations for system behavior are often guided by intuitive arithmetic.For systems composed of identical units,we anticipate synergy of the contributions from these units,where 1+1=2.Conversely,for systems built from opposing units,we expect cancellation of their contributions,where 1-1=0.This intuitive arithmetic has long underpinned our understanding of physical properties of materials,from electronic transport to optical responses.However,scientific breakthroughs often occur when nature reveals ways to circumvent these seemingly fundamental rules,opening new possibilities that challenge our deepest assumptions about material behavior.
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Project supported by the National Key Research and Development Program of China (Grant No. 2023YFA1406604)the National Natural Science Foundation of China (Grant Nos. 12274260, 12204306, 12122413, and 12474120)+1 种基金the Shandong Provincial Natural Science Foundation, China (Grant No. ZR2024YQ001)the Qilu Young Scholar Programs of Shandong University。
文摘We report the bifurcation of bound states in the continuum(BICs) in a dissipative cavity magnonic system, where a BIC splits into a pair of BICs. We theoretically analyze BICs in a dissipative cavity magnonic system and derive the critical condition for BICs bifurcation. Based on the theoretical results, we experimentally tune the dissipative photon–magnon coupling strength and demonstrate precise control over the detuning and number of BICs. When the dissipative coupling strength reaches a critical value, we observe the bifurcation of BICs, which is consistent with the theoretical prediction. Our systematic investigation of the evolution of BICs concerning the dissipative coupling strength and the discovery of the BIC bifurcation may enhance the sensitivity of BICs to external perturbations, potentially enabling applications in ultrasensitive detection.
基金funded by NSERC Discovery Grants, NSERC Discovery Accelerator Supplements, Innovation Proof-of-Concept Grant of Research Manitoba, and Faculty of Science Research Innovation and Commercialization Grant of University of Manitoba (C.-M.H.)。
文摘A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise. Like many low phase noise oscillators, a cavity magnonic oscillator faces the challenge that its narrow resonance profile is not well suited for injection locking amplification. This work presents an improved design for such an oscillator configured as an injection locking amplifier(ILA) with an extended lock range. The proposed design features a two-stage architecture, consisting of a pre-amplification oscillator and a cavity magnonic oscillator, separated by an isolator to prevent backward locking.By optimizing the circuit parameters of each stage, the proposed design achieved an order of magnitude increase in lock range, when compared to its predecessors, all while preserving the phase noise quality of the input, making it well-suited for narrowband, sensitive signal amplification. Furthermore, this work provides a method for using oscillators with high spectral purity as injection locking amplifiers.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12347156, 12174157, 12074150, and 12174158)the National Key Research and Development Program of China (Grant No. 2022YFA1405200)+1 种基金the Natural Science Foundation of Jiangsu Province (Grant No. BK20230516)the Scientific Research Project of Jiangsu University (Grant No. 550171001)。
文摘We investigate magnonic topology in the breathing Su–Schrieffer–Heeger(SSH) model, incorporating non-Hermitian effects. Our results demonstrate the coexistence of first-and second-order magnonic topologies, with non-Hermitian effects exhibiting size-dependent behavior. In two-dimensional systems, non-Hermitian terms induce a flat band and gap closure along high-symmetry paths, whereas in one-dimensional systems, a finite band gap persists for small system sizes. Additionally, the corner states remain robust, and a pronounced non-Hermitian skin effect emerges. Our findings provide new insights into magnon-based devices, emphasizing the impact of non-Hermitian effects on their design and functionality.
基金supported by the National Natural Science Foundation of China(Grant Nos.11264028 and 11072104)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(Grant No.2012MS0114)the School Scientific Research Funds of Inner Mongolia Normal University of China(Grant Nos.2013YJRC007 and 2013ZRYB19)
文摘Using the plane-wave expansion method, the spin-wave band structures of two-dimensional magnonic crystals consisting of square arrays of different shape scatterers are calculated numerically, and the effects of rotating rectangle and hexagon scaterers on the gaps are studied, respectively. The results show that the gaps can be substantially opened and tuned by rotating the scatterers. This approach should be helpful in designing magnonic crystals with desired gaps.
文摘We theoretically investigate the propagation characteristics of spin waves in skyrmion-based magnonic crystals. It is found that the dispersion relation can be manipulated by strains through magneto-elastic coupling. Especially, the allowed bands and forbidden bands in dispersion relations shift to higher frequency with strain changing from compressive to tensile,while shifting to lower frequency with strain changing from tensile to compressive. We also confirm that the spin wave with specific frequency can pass the magnonic crystal or be blocked by tuning the strains. The result provides an advanced platform for studying the tunable skyrmion-based spin wave devices.
基金Project supported by the National Key Research and Development Program of China(Grants No.2017YFA0206200)the National Natural Science Foundation of China(Grant Nos.51831012 and 12134107)the Beijing Natural Science Foundation(Grant No.Z201100004220006)。
文摘In this review,the recent developments in microelectronics,spintronics,and magnonics have been summarized and compared.Firstly,the history of the spintronics has been briefly reviewed.Moreover,the recent development of magnonics such as magnon-mediated current drag effect(MCDE),magnon valve effect(MVE),magnon junction effect(MJE),magnon blocking effect(MBE),magnon-mediated nonlocal spin Hall magnetoresistance(MNSMR),magnon-transfer torque(MTT)effect,and magnon resonant tunneling(MRT)effect,magnon skin effect(MSE),etc.,existing in magnon junctions or magnon heterojunctions,have been summarized and their potential applications in memory and logic devices,etc.,are prospected,from which we can see a promising future for spintronics and magnonics beyond micro-electronics.
基金Project supported by the National Natural Science Foundation of China(Grants Nos.11934010,U1801661,and 12174329)the Zhejiang Province Program for Science and Technology(Grant No.2020C01019)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2021FZZX001-02)the China Postdoctoral Science Foundation(Grant No.2019M660137)
文摘When there is a certain amount of field inhomogeneity,the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic(HMS)mode in addition to the uniform-precession Kittel mode.In cavity magnonics,we show the nonlinearity and heating-induced frequency shifts of the Kittel mode and HMS mode in a yttrium-iron-garnet(YIG)sphere.When the Kittel mode is driven to generate a certain number of excitations,the temperature of the whole YIG sample rises and the HMS mode can display an induced frequency shift,and vice versa.This cross effect provides a new method to study the magnetization dynamics and paves a way for novel cavity magnonic devices by including the heating effect as an operational degree of freedom.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.NSFC61974067 and 62374087)。
文摘Many studies of magnon–photon coupling are performed in the frequency domain for microwave photons.In this work,we present analytical results of eigenfrequency,eigenstates,and temporal dynamics for the coupling between ferromagnetic magnon and visible photon.In contrast to microwave photons,optical photons can be coupled with magnon in a dispersive interaction which produces both level repulsion and attraction by varying the magnon–photon frequency detuning.At resonance,the hybridized states are of linear polarization and circular polarization for level repulsion and level attraction respectively.As the detuning increases,the polarizations of level repulsion remain linear but those of level attraction vary from elliptical to linear polarizations.The temporal dynamics of level repulsion presents the beat-like behavior.The level attraction presents monotonous decay in the weak coupling regime but gives rise to instability in the strong coupling regime due to the magnon amplification.As the detuning is large,both magnon and photon amplitudes present a synchronizing oscillation.Our results are important for exploring the temporal evolution of magnon–photon coupling in the range of optical frequency and designing magnon-based timing devices.
基金supported by the U.S. Department of Energy, Office of Basic Energy Sciences under Award No. DE-SC0024339.
文摘The pseudospectral Landau-Lifshitz(PS-LL)model can describe atomic-scale magnetic exchange interactions within a continuum framework.This is achieved by employing a convolution kernel that models the nonlocal interaction in a grid-independent manner.Even though the PS-LL was originally introduced to address atomic exchange,any nonlocal kernel can be modeled.In the field of magnonics,the dipole field is fundamental to describe the dispersion relation of magnons,the quasiparticle representation of angular momentum.Because dipole-dipole interactions are longrange,numerical approaches typically rely on convolutions.Here,we demonstrate that the PS-LL model can be used to perform magnonic simulations with a single convolution kernel derived from analytical solutions.Wedemonstrate a twofold increase in computational speed compared with the full dipole calculation.This approach is valid insofar as the excitations are linear,which is typically the case for magnons.Our results have the potential to accelerate magnonic research,particularly for the inverse design method,where several simulations must be performed to achieve the desired outcome.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFA0301200)the National Natural Science Foundation of China(Grant Nos.11774022,and U1530401)
文摘We develop a theory for the magnon Kerr effect in a cavity magnonics system, consisting of magnons in a small yttrium iron garnet(YIG) sphere strongly coupled to cavity photons, and use it to study the bistability in this hybrid system. To have a complete picture of the bistability phenomenon, we analyze two different cases in driving the cavity magnonics system, i.e.,directly pumping the YIG sphere and the cavity, respectively. In both cases, the magnon frequency shifts due to the Kerr effect exhibit a similar bistable behavior but the corresponding critical powers are different. Moreover, we show how the bistability of the system can be demonstrated using the transmission spectrum of the cavity. Our results are valid in a wide parameter regime and generalize the theory of bistability in a cavity magnonics system.
基金support from the National Natural Science Foundation of China(Grant Nos.62131002 and 62071448)and the Fundamental Research Funds for the Central Universities(BNU).
文摘Recently,the photon–magnon coherent interaction based on the collective spins excitation in ferromagnetic materials has been achieved experimentally.Under the prospect,the magnons are proposed to store and process quantum information.Meanwhile,cavity-optomagnonics which describes the interaction between photons and magnons has been developing rapidly as an interesting topic of the cavity quantum electrodynamics.Here in this short review,we mainly introduce the recent theoretical and experimental progress in the field of optomagnetic coupling and optical manipulation based on cavity-optomagnonics.According to the frequency range of the electromagnetic field,cavity optomagnonics can be divided into microwave cavity optomagnonics and optical cavity optomagnonics,due to the different dynamics of the photon–magnon interaction.As the interaction between the electromagnetic field and the magnetic materials is enhanced in the cavity-optomagnonic system,it provides great significance to explore the nonlinear characteristics and quantum properties for different magnetic systems.More importantly,the electromagnetic response of optomagnonics covers the frequency range from gigahertz to terahertz which provides a broad frequency platform for the multi-mode controlling in quantum systems.
文摘A magnonic counterpart to optical frequency combs is vital for high-precision magnonic frequency metrology and spectroscopy.Here,we present an efficient mechanism for the generation of robust magnonic frequency combs in a yttrium iron garnet(YIG)sphere via magnetostrictive effects.We show that magnonic and vibrational dynamics in the ferrimagnetic sphere can be substantively modified in the presence of magnetostrictive effects,which results in degenerate and non-degenerate magnonic four-wave mixing and frequency conversion.Particularly,resonantly enhanced magnetostrictive effects can induce phonon laser action above a threshold,which leads to significant magnonic nonlinearity and enables a potentially practical scheme for the generation of robust magnonic frequency combs.Numerical calculations of both magnonic and phononic dynamics show excellent agreement with this theory.These results deepen our understanding of magnetostrictive interaction,open a novel and efficient pathway to realize magnonic frequency conversion and mixing in a magnonic device,and provide a sensitive tool for precision measurement.
基金supported by the National Key Research and Development Program of China (MOST)(Grant No.2022YFA1402800)the Chinese Academy of Sciences (CAS) Presidents International Fellowship Initiative (PIFI)(Grant No.2025PG0006)+3 种基金the National Natural Science Foundation of China (NSFC)(Grant Nos.51831012,12274437,and 52161160334)the CAS Project for Young Scientists in Basic Research (Grant No.YSBR-084)the CAS Youth Interdisciplinary Teamthe China Postdoctoral Science Foundation (Grant No.2025M773402)。
文摘Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling the automatic derivation of analytical expressions for the eigenmatrix elements via symbolic computation,eliminating the need for tedious manual calculations.Using this approach,we investigate the impact of magnetic hysteresis on magnon-magnon coupling in a system with interlayer Dzyaloshinskii-Moriya interaction(DMI).The magnetic hysteresis leads to an asymmetric magnetic field dependence of the resonance frequency and alters the number of degeneracy points between the pure optical and acoustic modes.Moreover,it can result in the coupling strength at the gap of the f–H phase diagram being nearly vanishing,contrary to the conventionally expected maximum.These results deepen the understanding of the effect of interlayer DMI on magnon–magnon coupling and the proposed universal method significantly streamlines the solving process of magnon–magnon coupling problems.
基金The project was funded by the European Research Council(ERC)Starting Grant 678309 MagnonCircuits and the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)-TRR 173-268565370(“Spin+X”,Project B01)the Nachwuchsring of the TU KaiserslauternR.V.acknowledges support of National Research Foundation of Ukraine(grant number 2020.02/0261).
文摘The field of magnonics,which aims at using spin waves as carriers in data-processing devices,has attracted increasing interest in recent years.We present and study micromagnetically a nonlinear nanoscale magnonic ring resonator device for enabling implementations of magnonic logic gates and neuromorphic magnonic circuits.In the linear regime,this device efficiently suppresses spin-wave transmission using the phenomenon of critical resonant coupling,thus exhibiting the behavior of a notch filter.By increasing the spin-wave input power,the resonance frequency is shifted,leading to transmission curves,depending on the frequency,reminiscent of the activation functions of neurons,or showing the characteristics of a power limiter.An analytical theory is developed to describe the transmission curve of magnonic ring resonators in the linear and nonlinear regimes,and is validated by a comprehensive micromagnetic study.The proposed magnonic ring resonator provides a multi-functional nonlinear building block for unconventional magnonic circuits.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0580000)the National Natural Science Foundation of China(Grant Nos.12204306,12122413,12227901,12474120,and U23A6002)+4 种基金the Science and Technology Commission of Shanghai Municipality(Grant Nos.23JC1404100 and 22JC1403300)the National Key R&D Program of China(Grant Nos.2022YFA1404603 and2023YFA1406604)the Shandong Provincial Natural Science FoundationChina(Grant No.ZR2024YQ001)the Qilu Young Scholar Programs of Shandong University。
文摘Strong coupling effects in magnonic systems are highly promising.They combine the advantages of different quasiparticles and enable energy transfer for coherent information processing.When driven by microwave,electric,or optical pumps,these coupling effects can give rise to intriguing nonlinear phenomena,which have become a focal point in the field of magnonics.This review systematically explores pump-engineered magnon-coupling systems from three perspectives:(1)pump-induced hybridization of magnon modes,(2)nonlinear manipulation of magnon dynamics,and(3)implementation of functional magnonic devices.Unlike conventional cavity-magnon interactions that are constrained by electromagnetic boundaries,pumped coupled magnons are liberated from these restrictions.They can operate over a broad frequency band rather than being confined to discrete modes.An example is the recently discovered pump-induced magnon mode(PIM).These magnons arise from the collective excitations of unsaturated spins driven by microwave pumps.They exhibit reduced damping and photon-number-sensitive splitting characteristics,facilitating waveform-controlled coupling strength and enhanced nonlinearity—features that support phenomena such as magnonic frequency combs(MFCs).By expanding this principle to electric pumping schemes,we bridge fundamental physics and practical device applications,enabling nonreciprocal switching and meter-scale strong coupling.These advances establish high-dimensional control capabilities for coupled magnonics and pave the way for their use as a promising platform for dynamically programmable devices,magnetic-field sensing,and coherent networks.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1402400)the National Natural Science Foundation of China(Grant No.12374119)the support of the Center for Nanoscience and Nanotechnology and the Supercomputing Center at Wuhan University in China。
文摘Spin waves in van der Waals magnets hold promise for magnonic devices and circuits down to the two-dimensional limit.However,their short decay lengths pose challenges for practical applications.Here,we report on a material platform consisting of a van der Waals magnet,Fe_(5)GeTe_(2)(FGT),and a ferrimagnetic insulator of yttrium iron garnet,Y_(3)Fe_(5)O_(12)(YIG),which supports the low-loss propagation of spin waves.Using broadband spin-wave spectroscopy,we observed an increase in spin-wave group velocity with decreasing temperature,which peaks at 30 K in the YIG and FGT/YIG films.This effect is ascribed to a change in the saturation magnetization of YIG and FGT/YIG at low temperature,resulting in a change in the spin-wave dispersion relations.Using micromagnetic simulations,we further investigated spin-wave propagation in an FGT/YIG bilayer and revealed a longer spin-wave decay length in the bilayer than in a single FGT layer,which is due to the lower effective damping in the bilayer.Moreover,asymmetric spin-wave dispersion,induced by a chiral dipolar interaction between the YIG and FGT layers,enables nonreciprocal control of spin-wave propagation.
基金supported by the National Natural Science Foundation of China(Grant Nos.12174129,T2394475,and T2394470)。
文摘Altermagnets,a new type of collinear antiferromagnet,exhibiting non-degenerate electron and magnon dispersion in momentum space have attracted intensive research attention.We theoretically analyze the origin and feature of chiral magnon splitting in representative altermagnets including tetragonal RuO_(2),hexagonal MnTe,and orthorhombic LaMnO_(3).The magnon spin transport properties including spin Seebeck and spin Nernst coefcients have been investigated.Through these materials,we demonstrate the diference of chiral splitting in d-wave and g-wave antiferromagnet on magnon transport.RuO2with planar magnon splitting exhibits signifcant magnon spin Nernst and magnon spin Seebeck anisotropy in(110)and(001)planes,whereas MnTe,due to its bulk-like magnon splitting,is incapable of producing magnon spin Nernst efect.Our work may provide in-depth understanding on the mechanisms of nonrelativistic magnon splitting and thermal spin transport in altermagnets.
基金supported by the National Key R&D Program of China (Grant No.2022YFA1403203)the National Natural Science Funds for Distinguished Young Scholar (Grant No.52325105)+2 种基金the National Natural Science Foundation of China (Grant Nos.12274411,12241405,52250418,and12404185)the Basic Research Program of the Chinese Academy of Sciences (CAS) Based on Major Scientific Infrastructures (Grant No.JZHKYPT-2021-08)the CAS Project for Young Scientists in Basic Research (Grant No.YSBR-084)。
文摘Magnon spin currents in insulating magnets are useful for low-power spintronics. However, in magnets stacked by antiferromagnetic(AFM) exchange coupling, which have recently aroused significant interest for potential applications in spintronics, Bose–Einstein distribution populates magnon states across all energies from opposite eigenmodes, and hence the magnon spin current is largely compensated. Contrary to this common observation,here, we show that magnets with X-type AFM stacking, where opposite magnetic sublattices form orthogonal intersecting chains, support giant magnon spin currents with minimal compensation. Our model Hamiltonian calculations predict magnetic chain locking of magnon spin currents in these X-type magnets, significantly reducing their compensation ratio. In addition, the one-dimensional nature of the chain-like magnetic sublattices enhances magnon spin conductivities surpassing those of two-dimensional ferromagnets and canonical altermagnets. Notably, uncompensated X-type magnets, such as odd-layer antiferromagnets and ferrimagnets, can exhibit magnon spin currents polarized opposite to those expected by their net magnetization. These unprecedented properties of X-type magnets, combined with their inherent advantages resulting from AFM coupling, offer a promising new path for low-power high-performance spintronics.
