Spinel compounds are of great interest in both fundamental and application-oriented perspectives due to the geometric magnetic frustration inherent to their lattice and the resulting complex magnetic states.Here,we ap...Spinel compounds are of great interest in both fundamental and application-oriented perspectives due to the geometric magnetic frustration inherent to their lattice and the resulting complex magnetic states.Here,we applied x-ray diffraction,magnetization,heat capacity and powder inelastic neutron scattering measurements,along with theoretical calculations,to study the exotic properties of chromite-spinel oxides CoCr_(2)O_(4) and MnCr_(2)O_(4).The temperature dependence of the phonon spectra provides an insight into the correlation between oxygen motion and the magnetic order,as well as the magnetoelectric effect in the ground state of MnCr_(2)O_(4).Moreover,spin-wave excitations in CoCr_(2)O_(4) and MnCr_(2)O_(4) are compared with Heisenberg model calculations.This approach enables the precise determination of exchange energies and offers a comprehensive understanding of the spin dynamics and relevant exchange interactions in complicated spiral spin ordering.展开更多
As a typical two-dimensional frustrated quantum magnet,the triangular-lattice antiferromagnet exhibits a series of exotic states from the complicated interplay of the lattice,spin,electron,and orbit with quantum and t...As a typical two-dimensional frustrated quantum magnet,the triangular-lattice antiferromagnet exhibits a series of exotic states from the complicated interplay of the lattice,spin,electron,and orbit with quantum and thermal fluctuations.From the ground state of a triangular-lattice Heisenberg antiferromagnet with coplanar 120o ordering,a series of magnetization anomalies can manifest under a magnetic field,such as the 1/3 magnetization plateau(Ms/3)and umbrella-shaped phase.This Ms/3 plateau state is recognized as an up-up-down structure stabilized by the quantum effect.By surveying theoretical research and experimental measurements on triangularlattice antiferromagnets,this review article describes the current understanding of the magnetic properties of triple-perovskite antiferromagnets A_(3)MB_(2)O_(9)(A=Ba,Ca,and Sr;M=Co,Ni,and Mn;B=Sb,Nb).Through examining both the bulk properties and spin dynamics,fascinating insights into the quantum effect on the triangular lattice are discussed.展开更多
In solids,the reservation of symmetries defines the types of topological invariants that classify various topological quantum materials[1–3].Among them,the time-reversal symmetry(TRS)is the most fundamental,which pla...In solids,the reservation of symmetries defines the types of topological invariants that classify various topological quantum materials[1–3].Among them,the time-reversal symmetry(TRS)is the most fundamental,which plays key role in topological helical edge or surface states.Nevertheless,breaking TRS in topological materials typically gives rise to unexpected exotic states,such as magnetic Weyl semimetals,quantum anomalous Hall insulators,and axion insulators.展开更多
基金the financial support from the National Key Research and Development Program of China(Grant No.2022YFA1402702)the National Science Foundation of China(Grant Nos.U2032213 and 12004243)+8 种基金the National Science Foundation of China(Grant No.12274412)the Interdisciplinary Program of Wuhan National High Magnetic Field Center(Grant No.WHMFC 202122)Huazhong University of Science and Technologythe support from the National Natural Science Foundation of China(Grant No.52101236)Guangdong Basic and Applied Basic Research Foundation(Grant No.2021B1515140014)the Guangdong Provincial Key Laboratory of Extreme Conditionsfinancial support from the National Key Research and Development Program of China(Grant Nos.2021YFA1600201 and 2023YFA1607402)the support of NSF-DMR-2003117supported by a beamtime allocation RB1910163 from the Science and Technology Facilities Council。
文摘Spinel compounds are of great interest in both fundamental and application-oriented perspectives due to the geometric magnetic frustration inherent to their lattice and the resulting complex magnetic states.Here,we applied x-ray diffraction,magnetization,heat capacity and powder inelastic neutron scattering measurements,along with theoretical calculations,to study the exotic properties of chromite-spinel oxides CoCr_(2)O_(4) and MnCr_(2)O_(4).The temperature dependence of the phonon spectra provides an insight into the correlation between oxygen motion and the magnetic order,as well as the magnetoelectric effect in the ground state of MnCr_(2)O_(4).Moreover,spin-wave excitations in CoCr_(2)O_(4) and MnCr_(2)O_(4) are compared with Heisenberg model calculations.This approach enables the precise determination of exchange energies and offers a comprehensive understanding of the spin dynamics and relevant exchange interactions in complicated spiral spin ordering.
文摘As a typical two-dimensional frustrated quantum magnet,the triangular-lattice antiferromagnet exhibits a series of exotic states from the complicated interplay of the lattice,spin,electron,and orbit with quantum and thermal fluctuations.From the ground state of a triangular-lattice Heisenberg antiferromagnet with coplanar 120o ordering,a series of magnetization anomalies can manifest under a magnetic field,such as the 1/3 magnetization plateau(Ms/3)and umbrella-shaped phase.This Ms/3 plateau state is recognized as an up-up-down structure stabilized by the quantum effect.By surveying theoretical research and experimental measurements on triangularlattice antiferromagnets,this review article describes the current understanding of the magnetic properties of triple-perovskite antiferromagnets A_(3)MB_(2)O_(9)(A=Ba,Ca,and Sr;M=Co,Ni,and Mn;B=Sb,Nb).Through examining both the bulk properties and spin dynamics,fascinating insights into the quantum effect on the triangular lattice are discussed.
基金support by National Key R&D Program of China(2023YFA1406304)supported by the National Key R&D Program of China(2022YFB3608000)+7 种基金National Natural Science Foundation of China(U2032208,11888101,92065201,U2032213,and 12222413)sponsored by Double First-Class Initiative Fund of ShanghaiTech University and the open projects from State Key Laboratory of Functional Materials for Informatics(SKL2022)supported by the National Key Research and Development Program of China(2022YFA1402704)the Natural Science Foundation of Shanghai(23ZR1482200 and 22ZR1473300)funded by the New Cornerstone Science FoundationChina National Postdoctoral Program for Innovative Talents(BX20240348)supported by ME2 project under Contract No.11227902 from the National Natural Science Foundation of Chinasupport from Analytical Instrumentation Center(#SPSTAIC10112914)。
文摘In solids,the reservation of symmetries defines the types of topological invariants that classify various topological quantum materials[1–3].Among them,the time-reversal symmetry(TRS)is the most fundamental,which plays key role in topological helical edge or surface states.Nevertheless,breaking TRS in topological materials typically gives rise to unexpected exotic states,such as magnetic Weyl semimetals,quantum anomalous Hall insulators,and axion insulators.
