In this work,Ga-doped Ce RhIn_(5) single crystals are grown by In/Ga flux method.Single-crystal X-ray diffraction,magnetic susceptibility,specific heat,and neutron diffraction measurements are utilized to characterize...In this work,Ga-doped Ce RhIn_(5) single crystals are grown by In/Ga flux method.Single-crystal X-ray diffraction,magnetic susceptibility,specific heat,and neutron diffraction measurements are utilized to characterize the sample quality and the antiferromagnetic transition temperature T_(N).By substituting In with Ga,T_(N) is slightly decreased,but the antiferromagnetic transition peaks in magnetic susceptibility and specific heat measurements are obviously broadened by external field along c-axis.By comparing with Zn-doped Ce RhIn_(5),it can be concluded that T_(N) is dominated by electron density,and the stiffness of antiferromagnetic transition is obviously reduced by Ga substitution.The substitution effects of Ga are possibly caused by forming heterogeneous local structures,which avoids quantum critical point,superconductivity,and non-Fermi liquid states.Investigations on Gadoped Ce RhIn_(5) help to comprehend the chemical substitution effects in Ce RhIn_(5),and the interaction between heterogeneous structure and long-range antiferromagnetic states.展开更多
High-quality antiferromagnetic(AFM)θ-phase manganese nitride(MnN)films were successfully grown on MgO(001)substrates by plasma-assisted molecular beam epitaxy.Structural analysis confirms the high-quality MnN film ha...High-quality antiferromagnetic(AFM)θ-phase manganese nitride(MnN)films were successfully grown on MgO(001)substrates by plasma-assisted molecular beam epitaxy.Structural analysis confirms the high-quality MnN film has a tetragonal distortion with a c/a ratio of~0.98.The film exhibits exceptional stability in both aqueous and ambient conditions,which is a crucial factor for practical applications.Electrical transport reveals its metallic behavior with an upturn at low temperatures,which could be attributed to the Kondo effect originated from nitrogen vacancy-induced magnetic impurities.Room temperature exchange bias has been demonstrated in a MnN/CoFeB heterostructure,verifying the AFM ordering of MnN.Considering its high Néel temperature~650 K,superior stability,and low-cost,this work highlights the epitaxial MnN films as a promising candidate for AFM spintronic applications.展开更多
The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic si...The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic simulations, we investigate recently synthesized ultrathin perovskite bismuth ferrite(BFO) films. Our numerical results reveal that, at the monolayer limit, the ferroelectricity of BFO is missing because the octahedral distortions are constrained. However, the monolayer bismuth ferrite is a topological antiferromagnetic metal with tunable bimeron magnetic structure. The dual topologically non-trivial characteristics make monolayer bismuth ferrite a multifunctional building block in future spintronic devices.展开更多
In this investigation,we delve into the interplay between strong interactions and intricate topological configurations,leading to emergent quantum states such as magnetic topological insulators.The crux of our researc...In this investigation,we delve into the interplay between strong interactions and intricate topological configurations,leading to emergent quantum states such as magnetic topological insulators.The crux of our research centers on elucidating how lattice symmetry modulates antiferromagnetic quantum Hall phenomena.Utilizing the spinful Harper-Hofstadter model enriched with a next-nearest-neighbor(NNN)hopping term,we discern a half-filling bandgap,paving the way for the manifestation of a quantum Hall insulator characterized by a Chern number,C=2.Upon integrating a checkerboardpatterned staggered potential(△)and the Hubbard interaction(U),the system exhibits complex dynamical behaviors.Marginal NNN hopping culminates in a Ne′el antiferromagnetic Mott insulator.In contrast,intensified hopping results in stripe antiferromagnetic configurations.Moreover,in the regime of limited NNN hopping,a C=1 Ne′el antiferromagnetic quantum Hall insulator emerges.A salient observation pertains to the manifestation of a C=1 antiferromagnetic quantum Hall insulator when spin-flip mechanisms are not offset by space group symmetries.These findings chart a pathway for further explorations into antiferromagnetic Quantum Hall States.展开更多
We theoretically study the effect of a uniform orbital magnetic field on spin waves in a triangular lattice tetrahedral antiferromagnetic insulator without spin–orbit coupling. Through symmetry analysis and microscop...We theoretically study the effect of a uniform orbital magnetic field on spin waves in a triangular lattice tetrahedral antiferromagnetic insulator without spin–orbit coupling. Through symmetry analysis and microscopic calculation, we show that the optical spin wave mode at the Brillouin zone center can acquire a small orbital magnetic moment, although it exhibits no magnetic moment from the Zeeman coupling. Our results are potentially applicable to intercalated van der Waals materials and twisted double-bilayer graphene.展开更多
Antiferromagnetic(AFM)spintronics have sparked extensive research interest in the field of information storage due to the considerable advantages offered by antiferromagnets,including non-volatile data storage,higher ...Antiferromagnetic(AFM)spintronics have sparked extensive research interest in the field of information storage due to the considerable advantages offered by antiferromagnets,including non-volatile data storage,higher storage density,and accelerating data processing.However,the manipulation and detection of internal AFM order in antiferromagnets hinders their applications in spintronic devices.Here,we proposed a design idea for an AFM material that is self-assembled from one-dimensional(1D)ferromagnetic(FM)chains.To validate this idea,we screened a two-dimensional(2D)selfassembled CrBr_(2)antiferromagnet of an AFM semiconductor from a large amount of data.This 2D CrBr_(2)antiferromagnet is composed of 1D FM CrBr_(2)chains that are arranged in a staggered and parallel configuration.In this type of antiferromagnet,the write-data operation of information is achieved in 1D FM chains,followed by a self-assembly process driving the assembly of 1D FM chains into an antiferromagnet.These constituent 1D FM chains become decoupled by external perturbations,such as heat,pressure,strain,etc.,thereby realizing the read-data operation of information.We anticipate that this antiferromagnet,composed of 1D FM chains,can be realized not only in the 1D to 2D system,but also is expected to expand to 2D to three-dimensional(3D)system,and even 1D to 3D system.展开更多
The spin pumping effect in magnetic heterostructures and multilayers is a highly effective method for the generationand transmission of spin currents. In the increasingly prominent synthetic antiferromagnetic structur...The spin pumping effect in magnetic heterostructures and multilayers is a highly effective method for the generationand transmission of spin currents. In the increasingly prominent synthetic antiferromagnetic structures, the two ferromagneticlayers demonstrate in-phase and out-of-phase states, corresponding to acoustic and optical precession modes. Withinthis context, our study explores the spin pumping effect in Py/Ru/Py synthetic antiferromagnetic structures across differentmodes. The heightened magnetic damping resulting from the spin pumping effect in the in-phase state initially decreaseswith increasing Py thickness before stabilizing. Conversely, in the out-of-phase state, the amplified damping exceeds thatof the in-phase state, suggesting a greater spin relaxation within this configuration, which demonstrates sensitivity to alterationsin static exchange interactions. These findings contribute to advancing the application of synthetic antiferromagneticstructures in magnonic devices.展开更多
Intercalated transition metal dichalcogenides(TMDCs)attract much attention due to their rich properties and potential applications.In this article,we grew successfully high-quality V_(1/3)TaS_(2) crystals by a vapor t...Intercalated transition metal dichalcogenides(TMDCs)attract much attention due to their rich properties and potential applications.In this article,we grew successfully high-quality V_(1/3)TaS_(2) crystals by a vapor transport method.We measured the magnetization,longitudinal resistivityρxx(T,H),Hall resistivityρxy(T,H),as well as performed calculations of the electronic band structure.It was found that V_(1/3)TaS_(2) is an A-type antiferromagnet with the Neel temperature T_(N)=6.20 K,and exhibits a negative magnetoresistance(MR)near T_(N).Both band structure calculations and Hall resistivity measurements demonstrated it is a magnetic semimetal.展开更多
A clear microscopic understanding of exchange bias is crucial for its application in magnetic recording, and further progress in this area is desired. Based on the results of our first-principles calculations and Mont...A clear microscopic understanding of exchange bias is crucial for its application in magnetic recording, and further progress in this area is desired. Based on the results of our first-principles calculations and Monte Carlo simulations,we present a theoretical proposal for a stacking-dependent exchange bias in two-dimensional compensated van der Waals ferromagnetic/antiferromagnetic bilayer heterostructures. The exchange bias effect emerges in stacking registries that accommodate inhomogeneous interlayer magnetic interactions between the ferromagnetic layer and different spin sublattices of the antiferromagnetic layer. Moreover, the on/off switching and polarity reversal of the exchange bias can be achieved by interlayer sliding, and the strength can be modulated using an external electric field. Our findings push the limits of exchange bias systems to extreme bilayer thickness in two-dimensional van der Waals heterostructures, potentially stimulating new experimental investigations and applications.展开更多
Recently,Chern insulators in an antiferromagnetic(AFM)phase have been suggested theoretically and predicted in a few materials.However,the experimental observation of two-dimensional(2D)AFM quantum anomalous Hall effe...Recently,Chern insulators in an antiferromagnetic(AFM)phase have been suggested theoretically and predicted in a few materials.However,the experimental observation of two-dimensional(2D)AFM quantum anomalous Hall effect is still a challenge to date.In this work,we propose that an AFM Chern insulator can be realized in a 2D monolayer of NiOsCl_(6)modulated by a compressive strain.Strain modulation is accessible experimentally and used widely in predicting and tuning topological nontrivial phases.With first-principles calculations,we have investigated the structural,magnetic,and electronic properties of NiOsCl_(6).Its stability has been confirmed through molecular dynamical simulations,elasticity constant,and phonon spectrum.It has a collinear AFM order,with opposite magnetic moments of 1.3μBon each Ni/Os atom,respectively,and the Neel temperature is estimated to be 93 K.In the absence of strain,it functions as an AFM insulator with a direct gap with spin-orbital coupling included.Compressive strain will induce a transition from a normal insulator to a Chern insulator characterized by a Chern number C=1,with a band gap of about 30 meV.This transition is accompanied by a structural distortion.Remarkably,the Chern insulator phase persists within the 3%-10%compressive strain range,offering an alternative platform for the utilization of AFM materials in spintronic devices.展开更多
Systemically angular and planar transport investigations are performed in layered antiferromagnetic(AF)V_(5)S_(8).In this AF system,obvious anomalous Hall effect(AHE)is observed with a large Hall angle of 0.1 compared...Systemically angular and planar transport investigations are performed in layered antiferromagnetic(AF)V_(5)S_(8).In this AF system,obvious anomalous Hall effect(AHE)is observed with a large Hall angle of 0.1 compared to that in ferromagnetic(FM)system.It can persist to the temperatures above AF transition and exhibit strong angular field dependence.The phase diagram reveals various magnetic states by rotating the applied field.By analyzing the anisotropic transport behavior,magnon contributions are revealed and exhibit obvious angular dependence with a spin-flop vanishing line.The observed prominent planar Hall effect and anisotropic magnetoresisitivity exhibit two-fold systematical angular dependent oscillations.These behaviors are attributed to the scattering from spin–orbital coupling instead of nontrivial topological origin.Our results reveal anisotropic interactions of magnetism and electron in V5S8,suggesting potential opportunities for the AF spintronic sensor and devices.展开更多
The study on temperature dependence of exchange bias field and coercivity is crucial to solving the writing/reading dilemma in magnetic recording.Motivated by recent experimental findings,a complete switch between exc...The study on temperature dependence of exchange bias field and coercivity is crucial to solving the writing/reading dilemma in magnetic recording.Motivated by recent experimental findings,a complete switch between exchange bias field and coercivity with temperature is proposed,and the performance,characterized by average switching temperature(T_(S))and switching temperature width(T_(W)),controlled by antiferromagnetic anisotropy(KAF)and exchange coupling(J_(AF))constants is studied based on a MonteCarlo simulation.The results show that a linear relationship between T_(S)and KAFis established when KAFis above a critical value,while T_(S)is weakly influenced by J_(AF).On the contrary,T_(W)is insensitive to KAF,while strongly depends on J_(AF).Besides overcoming thermal energy,the increase of KAFfor a small J_(AF)guarantees the completely frozen states in the antiferromagnetic layers during magnetizing at higher temperature,below which the exchange bias field exists with a negligible coercivity.Otherwise,for a large J_(AF),the uncompensated antiferromagnetic magnetization behavior during the ferromagnetic magnetization reversal becomes complicated,and the switching process in the low temperature range depends on the irreversibility of uncompensated antiferromagnetic magnetization reversal during magnetizing,while in the high temperature range mainly influenced by the field-cooling process,resulting in a large T_(W).This work provides an opportunity to control/optimize the performance of the temperatureinduced switch between unidirectional and uniaxial symmetries through precisely tuning KAFand/or J_(AF)to meet different application demands in the next generation information technology.展开更多
By use of the Hartree approximation and the method of multiple scales, we investigate quantum solitons and intrinsic localized modes in a one-dimensional antiferromagnetic chain. It is shown that there exist solitons ...By use of the Hartree approximation and the method of multiple scales, we investigate quantum solitons and intrinsic localized modes in a one-dimensional antiferromagnetic chain. It is shown that there exist solitons of two different quantum frequency bands： i.e., magnetic optical solitons and acoustic solitons. At the boundary of the Brillouin zone, these solitons becornc quantum intrinsic localized modes： their quantum eigenfrequencics are below the bottom of the harmonic optical frequency band and above the top of the harmonic acoustic frequency band.展开更多
Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and or...Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types. The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy. The equation of the critical stress is derived, which can judge whether the loops show hysteresis or not. Numerical calculations suggest that except for the magnitude of the mechanical stress, the relative orientation of the stress is also an important factor to tune the exchange bias effect.展开更多
In this work, the magnetic properties of Ising and XY antiferromagnetic thin-films are investigated each as a function of Neel temperature and thickness for layers （n = 2, 3, 4, 5, 6, and bulk （∞） by means of a me...In this work, the magnetic properties of Ising and XY antiferromagnetic thin-films are investigated each as a function of Neel temperature and thickness for layers （n = 2, 3, 4, 5, 6, and bulk （∞） by means of a mean-field and high temperature series expansion （HTSE） combined with Pade approximant calculations. The scaling law of magnetic susceptibility and magnetization is used to determine the critical exponent γ, veff （mean）, ratio of the critical exponents γ/v, and magnetic properties of Ising and XY antiferromagnetic thin-films for different thickness layers n = 2, 3, 4, 5, 6, and bulk （∞）.展开更多
It has recently been demonstrated that various topological states, including Dirac, Weyl, nodal-line, and triplepoint semimetal phases, can emerge in antiferromagnetic(AFM) half-Heusler compounds. However, how to dete...It has recently been demonstrated that various topological states, including Dirac, Weyl, nodal-line, and triplepoint semimetal phases, can emerge in antiferromagnetic(AFM) half-Heusler compounds. However, how to determine the AFM structure and to distinguish different topological phases from transport behaviors remains unknown. We show that, due to the presence of combined time-reversal and fractional translation symmetry, the recently proposed second-order nonlinear Hall effect can be used to characterize different topological phases with various AFM configurations. Guided by the symmetry analysis, we obtain expressions of the Berry curvature dipole for different AFM configurations. Based on the effective model, we explicitly calculate the Berry curvature dipole, which is found to be vanishingly small for the triple-point semimetal phase, and large in the Weyl semimetal phase. Our results not only put forward an effective method for the identification of magnetic orders and topological phases in AFM half-Heusler materials, but also suggest these materials as a versatile platform for engineering the nonlinear Hall effect.展开更多
We investigate the ultrafast spin dynamics of an antiferromagnet in a ferromagnet/antiferromagnet heterostructure Fe/GdFeO_(3) via an all-optical method.After laser irradiation,the terahertz spin precession is hard to...We investigate the ultrafast spin dynamics of an antiferromagnet in a ferromagnet/antiferromagnet heterostructure Fe/GdFeO_(3) via an all-optical method.After laser irradiation,the terahertz spin precession is hard to be excited in a bare GdFeO_(3) without spin reorientation phase but efficiently in Fe/GdFeO_(3).Both quasi-ferromagnetic and impurity modes,as well as a phonon mode,are observed.We attribute it to the optical modification of interfacial exchange coupling between Fe and GdFeO3.Moreover,the excitation efficiency of dynamics can be modified significantly via the pump laser influence.Our results elucidate that the interfacial exchange coupling is a feasible stimulation to efficiently excite terahertz spin dynamics in antiferromagnets.It will expand the exploration of terahertz spin dynamics for antiferromagnet-based opto-spintronic devices.展开更多
We exploit a scheme to obtain a long-lived entanglement using a driven central spin interacting with an antiferromagnetic spin bath. Our numerical results show the effects of different parameters on the population inv...We exploit a scheme to obtain a long-lived entanglement using a driven central spin interacting with an antiferromagnetic spin bath. Our numerical results show the effects of different parameters on the population inversion and the entanglement dynamics in terms of the linear entropy. It is shown that the long-lived entanglement is an intriguing result corresponding to the collapse region of the atomic inversion. As illustration, we examine the long-time interaction of the entanglement under the resonance and off-resonance regimes.展开更多
We report the detailed physical properties of quaternary compound Ba2BiFeS5 with the key structural ingredient of isolated FeS4 tetrahedra.Magnetization and heat capacity measurements clearly indicate that Ba2BiFeS5 h...We report the detailed physical properties of quaternary compound Ba2BiFeS5 with the key structural ingredient of isolated FeS4 tetrahedra.Magnetization and heat capacity measurements clearly indicate that Ba2BiFeS5 has a paramagnetic to antiferromagnetic transition at about 30 K.The calculated magnetic entropy above ordering temperature is much smaller than theoretical value for high-spin Fe^3+ion with S=5/2,implying the possible short-range antiferromagnetic fluctuation in Ba2BiFeS5.展开更多
The classical frustrated antiferromagnetic J_1–J_2 model is considered in a description of the classical spin wave for a vector spin system. Its ground state(GS) spin ordering is analyzed by minimizing its energy. Ou...The classical frustrated antiferromagnetic J_1–J_2 model is considered in a description of the classical spin wave for a vector spin system. Its ground state(GS) spin ordering is analyzed by minimizing its energy. Our analytical derivations show that all the spins in the GS phase must lie in planes that are parallel to each other. When applying the derived formulations to concrete lattices such as the square and simple cubic lattices, we find that in the large J_2 region, a large continuous GS degeneracy concluded by a qualitative analysis is lifted, and collinear striped ordering is selected as the GS phase.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1402203)the National Natural Science Foundations of China(Grant Nos.12174065 and 12104424)the Shanghai Municipal Science and Technology(Grant No.2019SHZDZX01)。
文摘In this work,Ga-doped Ce RhIn_(5) single crystals are grown by In/Ga flux method.Single-crystal X-ray diffraction,magnetic susceptibility,specific heat,and neutron diffraction measurements are utilized to characterize the sample quality and the antiferromagnetic transition temperature T_(N).By substituting In with Ga,T_(N) is slightly decreased,but the antiferromagnetic transition peaks in magnetic susceptibility and specific heat measurements are obviously broadened by external field along c-axis.By comparing with Zn-doped Ce RhIn_(5),it can be concluded that T_(N) is dominated by electron density,and the stiffness of antiferromagnetic transition is obviously reduced by Ga substitution.The substitution effects of Ga are possibly caused by forming heterogeneous local structures,which avoids quantum critical point,superconductivity,and non-Fermi liquid states.Investigations on Gadoped Ce RhIn_(5) help to comprehend the chemical substitution effects in Ce RhIn_(5),and the interaction between heterogeneous structure and long-range antiferromagnetic states.
文摘High-quality antiferromagnetic(AFM)θ-phase manganese nitride(MnN)films were successfully grown on MgO(001)substrates by plasma-assisted molecular beam epitaxy.Structural analysis confirms the high-quality MnN film has a tetragonal distortion with a c/a ratio of~0.98.The film exhibits exceptional stability in both aqueous and ambient conditions,which is a crucial factor for practical applications.Electrical transport reveals its metallic behavior with an upturn at low temperatures,which could be attributed to the Kondo effect originated from nitrogen vacancy-induced magnetic impurities.Room temperature exchange bias has been demonstrated in a MnN/CoFeB heterostructure,verifying the AFM ordering of MnN.Considering its high Néel temperature~650 K,superior stability,and low-cost,this work highlights the epitaxial MnN films as a promising candidate for AFM spintronic applications.
基金supported by the National Natural Science Foundation of China (Grant No. 12174382)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDB0460000 and XDB28000000)the Innovation Program for Quantum Science and Technology (Grant Nos. 2024ZD0300104 and 2021ZD0302600)。
文摘The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic simulations, we investigate recently synthesized ultrathin perovskite bismuth ferrite(BFO) films. Our numerical results reveal that, at the monolayer limit, the ferroelectricity of BFO is missing because the octahedral distortions are constrained. However, the monolayer bismuth ferrite is a topological antiferromagnetic metal with tunable bimeron magnetic structure. The dual topologically non-trivial characteristics make monolayer bismuth ferrite a multifunctional building block in future spintronic devices.
文摘In this investigation,we delve into the interplay between strong interactions and intricate topological configurations,leading to emergent quantum states such as magnetic topological insulators.The crux of our research centers on elucidating how lattice symmetry modulates antiferromagnetic quantum Hall phenomena.Utilizing the spinful Harper-Hofstadter model enriched with a next-nearest-neighbor(NNN)hopping term,we discern a half-filling bandgap,paving the way for the manifestation of a quantum Hall insulator characterized by a Chern number,C=2.Upon integrating a checkerboardpatterned staggered potential(△)and the Hubbard interaction(U),the system exhibits complex dynamical behaviors.Marginal NNN hopping culminates in a Ne′el antiferromagnetic Mott insulator.In contrast,intensified hopping results in stripe antiferromagnetic configurations.Moreover,in the regime of limited NNN hopping,a C=1 Ne′el antiferromagnetic quantum Hall insulator emerges.A salient observation pertains to the manifestation of a C=1 antiferromagnetic quantum Hall insulator when spin-flip mechanisms are not offset by space group symmetries.These findings chart a pathway for further explorations into antiferromagnetic Quantum Hall States.
基金Project supported by the National Key R&D Program of China (Grant No. 2022YFA1403800)the National Natural Science Foundation of China (Grant Nos. 12250008 and 12188101)+1 种基金the Project for Young Scientists in Basic Research (Grant No. YSBR-059)performed in part at the Aspen Center for Physics, supported by the National Natural Science Foundation of China (Grant No. PHY2210452)。
文摘We theoretically study the effect of a uniform orbital magnetic field on spin waves in a triangular lattice tetrahedral antiferromagnetic insulator without spin–orbit coupling. Through symmetry analysis and microscopic calculation, we show that the optical spin wave mode at the Brillouin zone center can acquire a small orbital magnetic moment, although it exhibits no magnetic moment from the Zeeman coupling. Our results are potentially applicable to intercalated van der Waals materials and twisted double-bilayer graphene.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12435001,12304006,and 12404265)the Natural Science Foundation of Shanghai,China(Grant No.23JC1401400)+1 种基金the Fundamental Research Funds for the Central Universities of East China University,the Natural Science Foundation of WIUCAS(Grant No.WIUCASQD2023004)the Natural Science Foundation of Wenzhou(Grant No.L2023005)。
文摘Antiferromagnetic(AFM)spintronics have sparked extensive research interest in the field of information storage due to the considerable advantages offered by antiferromagnets,including non-volatile data storage,higher storage density,and accelerating data processing.However,the manipulation and detection of internal AFM order in antiferromagnets hinders their applications in spintronic devices.Here,we proposed a design idea for an AFM material that is self-assembled from one-dimensional(1D)ferromagnetic(FM)chains.To validate this idea,we screened a two-dimensional(2D)selfassembled CrBr_(2)antiferromagnet of an AFM semiconductor from a large amount of data.This 2D CrBr_(2)antiferromagnet is composed of 1D FM CrBr_(2)chains that are arranged in a staggered and parallel configuration.In this type of antiferromagnet,the write-data operation of information is achieved in 1D FM chains,followed by a self-assembly process driving the assembly of 1D FM chains into an antiferromagnet.These constituent 1D FM chains become decoupled by external perturbations,such as heat,pressure,strain,etc.,thereby realizing the read-data operation of information.We anticipate that this antiferromagnet,composed of 1D FM chains,can be realized not only in the 1D to 2D system,but also is expected to expand to 2D to three-dimensional(3D)system,and even 1D to 3D system.
基金National Key Research and De-velopment Program of China(Grant No.2023YFA1406603)the National Natural Science Foundation of China(Grant Nos.52071079,12274071,12374112,and T2394473)Jiangsu Funding Program for Excellent Postdoctoral Talent(Grant No.2023ZB491).
文摘The spin pumping effect in magnetic heterostructures and multilayers is a highly effective method for the generationand transmission of spin currents. In the increasingly prominent synthetic antiferromagnetic structures, the two ferromagneticlayers demonstrate in-phase and out-of-phase states, corresponding to acoustic and optical precession modes. Withinthis context, our study explores the spin pumping effect in Py/Ru/Py synthetic antiferromagnetic structures across differentmodes. The heightened magnetic damping resulting from the spin pumping effect in the in-phase state initially decreaseswith increasing Py thickness before stabilizing. Conversely, in the out-of-phase state, the amplified damping exceeds thatof the in-phase state, suggesting a greater spin relaxation within this configuration, which demonstrates sensitivity to alterationsin static exchange interactions. These findings contribute to advancing the application of synthetic antiferromagneticstructures in magnonic devices.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFA1403202)the National Natural Science Foundation of China(Grant Nos.NSFC-12074335,11974095,5177115,11974095,and 12188101)the Natural Science Foundation of Shaanxi Province of China(Grant No.2022JM-028).
文摘Intercalated transition metal dichalcogenides(TMDCs)attract much attention due to their rich properties and potential applications.In this article,we grew successfully high-quality V_(1/3)TaS_(2) crystals by a vapor transport method.We measured the magnetization,longitudinal resistivityρxx(T,H),Hall resistivityρxy(T,H),as well as performed calculations of the electronic band structure.It was found that V_(1/3)TaS_(2) is an A-type antiferromagnet with the Neel temperature T_(N)=6.20 K,and exhibits a negative magnetoresistance(MR)near T_(N).Both band structure calculations and Hall resistivity measurements demonstrated it is a magnetic semimetal.
基金Project supported by the National Key Research and Development Program of China (Grant No.2019YFA0210004)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No.XDB30000000)+1 种基金the Fundamental Research Funds for the Central Universities (Grant No.WK3510000013)the National Supercomputing Center in Tianjin。
文摘A clear microscopic understanding of exchange bias is crucial for its application in magnetic recording, and further progress in this area is desired. Based on the results of our first-principles calculations and Monte Carlo simulations,we present a theoretical proposal for a stacking-dependent exchange bias in two-dimensional compensated van der Waals ferromagnetic/antiferromagnetic bilayer heterostructures. The exchange bias effect emerges in stacking registries that accommodate inhomogeneous interlayer magnetic interactions between the ferromagnetic layer and different spin sublattices of the antiferromagnetic layer. Moreover, the on/off switching and polarity reversal of the exchange bias can be achieved by interlayer sliding, and the strength can be modulated using an external electric field. Our findings push the limits of exchange bias systems to extreme bilayer thickness in two-dimensional van der Waals heterostructures, potentially stimulating new experimental investigations and applications.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12104183,52173283,and 62071200)the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2021MA040 and ZR2023MA091)+2 种基金the Taishan Scholar Program of Shandong Province,China(Grant No.ts20190939)the Independent Cultivation Program of Innovation Team of Jinan City(Grant No.2021GXRC043)supported by high-performance computing platform at University of Jinan。
文摘Recently,Chern insulators in an antiferromagnetic(AFM)phase have been suggested theoretically and predicted in a few materials.However,the experimental observation of two-dimensional(2D)AFM quantum anomalous Hall effect is still a challenge to date.In this work,we propose that an AFM Chern insulator can be realized in a 2D monolayer of NiOsCl_(6)modulated by a compressive strain.Strain modulation is accessible experimentally and used widely in predicting and tuning topological nontrivial phases.With first-principles calculations,we have investigated the structural,magnetic,and electronic properties of NiOsCl_(6).Its stability has been confirmed through molecular dynamical simulations,elasticity constant,and phonon spectrum.It has a collinear AFM order,with opposite magnetic moments of 1.3μBon each Ni/Os atom,respectively,and the Neel temperature is estimated to be 93 K.In the absence of strain,it functions as an AFM insulator with a direct gap with spin-orbital coupling included.Compressive strain will induce a transition from a normal insulator to a Chern insulator characterized by a Chern number C=1,with a band gap of about 30 meV.This transition is accompanied by a structural distortion.Remarkably,the Chern insulator phase persists within the 3%-10%compressive strain range,offering an alternative platform for the utilization of AFM materials in spintronic devices.
基金Project supported by the open research fund of Songshan Lake Materials Laboratory(Grant No.2021SLABFN11)the National Natural Science Foundation of China(Grant Nos.U2130101 and 92165204)+5 种基金Natural Science Foundation of Guangdong Province(Grant No.2022A1515010035)Guangzhou Basic and Applied Basic Research Foundation(Grant No.202201011798)the Open Project of Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices(Grant No.2022B1212010008)the Open Project of Key Laboratory of Optoelectronic Materials and Technologies(Grant No.OEMT-2023-ZTS-01)the National Key R&D Program of China(Grant Nos.2023YFF0718400 and 2023YFA1406500)(national)college students innovation and entrepreneurship training program,Sun Yat-sen University(Grant No.202310359).
文摘Systemically angular and planar transport investigations are performed in layered antiferromagnetic(AF)V_(5)S_(8).In this AF system,obvious anomalous Hall effect(AHE)is observed with a large Hall angle of 0.1 compared to that in ferromagnetic(FM)system.It can persist to the temperatures above AF transition and exhibit strong angular field dependence.The phase diagram reveals various magnetic states by rotating the applied field.By analyzing the anisotropic transport behavior,magnon contributions are revealed and exhibit obvious angular dependence with a spin-flop vanishing line.The observed prominent planar Hall effect and anisotropic magnetoresisitivity exhibit two-fold systematical angular dependent oscillations.These behaviors are attributed to the scattering from spin–orbital coupling instead of nontrivial topological origin.Our results reveal anisotropic interactions of magnetism and electron in V5S8,suggesting potential opportunities for the AF spintronic sensor and devices.
基金financially supported by the National Natural Science Foundation of China(No.11774045)the Joint Research Fund Liaoning-Shenyang National Laboratory for Materials Science(No.20180510008)。
文摘The study on temperature dependence of exchange bias field and coercivity is crucial to solving the writing/reading dilemma in magnetic recording.Motivated by recent experimental findings,a complete switch between exchange bias field and coercivity with temperature is proposed,and the performance,characterized by average switching temperature(T_(S))and switching temperature width(T_(W)),controlled by antiferromagnetic anisotropy(KAF)and exchange coupling(J_(AF))constants is studied based on a MonteCarlo simulation.The results show that a linear relationship between T_(S)and KAFis established when KAFis above a critical value,while T_(S)is weakly influenced by J_(AF).On the contrary,T_(W)is insensitive to KAF,while strongly depends on J_(AF).Besides overcoming thermal energy,the increase of KAFfor a small J_(AF)guarantees the completely frozen states in the antiferromagnetic layers during magnetizing at higher temperature,below which the exchange bias field exists with a negligible coercivity.Otherwise,for a large J_(AF),the uncompensated antiferromagnetic magnetization behavior during the ferromagnetic magnetization reversal becomes complicated,and the switching process in the low temperature range depends on the irreversibility of uncompensated antiferromagnetic magnetization reversal during magnetizing,while in the high temperature range mainly influenced by the field-cooling process,resulting in a large T_(W).This work provides an opportunity to control/optimize the performance of the temperatureinduced switch between unidirectional and uniaxial symmetries through precisely tuning KAFand/or J_(AF)to meet different application demands in the next generation information technology.
基金Project supported by the Natural Science Foundation of Hunan Province, China （Grant No 03JJY6008）.
文摘By use of the Hartree approximation and the method of multiple scales, we investigate quantum solitons and intrinsic localized modes in a one-dimensional antiferromagnetic chain. It is shown that there exist solitons of two different quantum frequency bands： i.e., magnetic optical solitons and acoustic solitons. At the boundary of the Brillouin zone, these solitons becornc quantum intrinsic localized modes： their quantum eigenfrequencics are below the bottom of the harmonic optical frequency band and above the top of the harmonic acoustic frequency band.
基金Supported by the Youth Science Foundation of Shanxi Province under Grant No 2013021010-3the National Natural Science Foundation of China under Grant Nos 61434002 and 11404202
文摘Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types. The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy. The equation of the critical stress is derived, which can judge whether the loops show hysteresis or not. Numerical calculations suggest that except for the magnitude of the mechanical stress, the relative orientation of the stress is also an important factor to tune the exchange bias effect.
文摘In this work, the magnetic properties of Ising and XY antiferromagnetic thin-films are investigated each as a function of Neel temperature and thickness for layers （n = 2, 3, 4, 5, 6, and bulk （∞） by means of a mean-field and high temperature series expansion （HTSE） combined with Pade approximant calculations. The scaling law of magnetic susceptibility and magnetization is used to determine the critical exponent γ, veff （mean）, ratio of the critical exponents γ/v, and magnetic properties of Ising and XY antiferromagnetic thin-films for different thickness layers n = 2, 3, 4, 5, 6, and bulk （∞）.
基金Supported by the National Natural Science Foundation of China (Grant Nos.11834006,12074181,and 11674165)the Natural Science Foundation of Jiangsu Province (Grant No.BK20200007)+1 种基金the Fok Ying-Tong Education Foundation of China (Grant No.161006)the Fundamental Research Funds for the Central Universities (Grant No.020414380149)。
文摘It has recently been demonstrated that various topological states, including Dirac, Weyl, nodal-line, and triplepoint semimetal phases, can emerge in antiferromagnetic(AFM) half-Heusler compounds. However, how to determine the AFM structure and to distinguish different topological phases from transport behaviors remains unknown. We show that, due to the presence of combined time-reversal and fractional translation symmetry, the recently proposed second-order nonlinear Hall effect can be used to characterize different topological phases with various AFM configurations. Guided by the symmetry analysis, we obtain expressions of the Berry curvature dipole for different AFM configurations. Based on the effective model, we explicitly calculate the Berry curvature dipole, which is found to be vanishingly small for the triple-point semimetal phase, and large in the Weyl semimetal phase. Our results not only put forward an effective method for the identification of magnetic orders and topological phases in AFM half-Heusler materials, but also suggest these materials as a versatile platform for engineering the nonlinear Hall effect.
基金Project supported by the National Key Research Program of China(Grant Nos.2018YFF01010303,2017YFB0702702,and 2016YFA0300701)the National Natural Sciences Foundation of China(Grant Nos.52031015,1187411,51427801,and 51871235)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant Nos.QYZDJ-SSW-JSC023,KJZD-SW-M01,and ZDYZ2012-2).
文摘We investigate the ultrafast spin dynamics of an antiferromagnet in a ferromagnet/antiferromagnet heterostructure Fe/GdFeO_(3) via an all-optical method.After laser irradiation,the terahertz spin precession is hard to be excited in a bare GdFeO_(3) without spin reorientation phase but efficiently in Fe/GdFeO_(3).Both quasi-ferromagnetic and impurity modes,as well as a phonon mode,are observed.We attribute it to the optical modification of interfacial exchange coupling between Fe and GdFeO3.Moreover,the excitation efficiency of dynamics can be modified significantly via the pump laser influence.Our results elucidate that the interfacial exchange coupling is a feasible stimulation to efficiently excite terahertz spin dynamics in antiferromagnets.It will expand the exploration of terahertz spin dynamics for antiferromagnet-based opto-spintronic devices.
文摘We exploit a scheme to obtain a long-lived entanglement using a driven central spin interacting with an antiferromagnetic spin bath. Our numerical results show the effects of different parameters on the population inversion and the entanglement dynamics in terms of the linear entropy. It is shown that the long-lived entanglement is an intriguing result corresponding to the collapse region of the atomic inversion. As illustration, we examine the long-time interaction of the entanglement under the resonance and off-resonance regimes.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0300504)the National Natural Science Foundation of China(Grant Nos.11574394,11774423,and 11822412)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(RUC)(Grant Nos.15XNLQ07,18XNLG14,and 19XNLG17)
文摘We report the detailed physical properties of quaternary compound Ba2BiFeS5 with the key structural ingredient of isolated FeS4 tetrahedra.Magnetization and heat capacity measurements clearly indicate that Ba2BiFeS5 has a paramagnetic to antiferromagnetic transition at about 30 K.The calculated magnetic entropy above ordering temperature is much smaller than theoretical value for high-spin Fe^3+ion with S=5/2,implying the possible short-range antiferromagnetic fluctuation in Ba2BiFeS5.
基金Supported by the National Natural Science Foundation of China under Grant No 11774002
文摘The classical frustrated antiferromagnetic J_1–J_2 model is considered in a description of the classical spin wave for a vector spin system. Its ground state(GS) spin ordering is analyzed by minimizing its energy. Our analytical derivations show that all the spins in the GS phase must lie in planes that are parallel to each other. When applying the derived formulations to concrete lattices such as the square and simple cubic lattices, we find that in the large J_2 region, a large continuous GS degeneracy concluded by a qualitative analysis is lifted, and collinear striped ordering is selected as the GS phase.
