1. Thermal evolution of spin excitations in honeycomb Ising antiferromagnetic FePSe3
- Author
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Lebing Chen, Xiaokun Teng, Ding Hu, Feng Ye, Garrett E. Granroth, Ming Yi, Jae-Ho Chung, Robert J. Birgeneau, and Pengcheng Dai
- Subjects
Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Atomic physics. Constitution and properties of matter ,QC170-197 - Abstract
Abstract We use elastic and inelastic neutron scattering (INS) to study the antiferromagnetic (AF) phase transitions and spin excitations in the two-dimensional (2D) zig-zag antiferromagnet FePSe3. By determining the magnetic order parameter across the AF phase transition, we conclude that the AF phase transition in FePSe3 is first-order in nature. In addition, our INS measurements reveal that the spin waves in the AF ordered state have a large easy-axis magnetic anisotropy gap, consistent with an Ising Hamiltonian, and possible biquadratic magnetic exchange interactions. On warming across T N, we find that dispersive spin excitations associated with three-fold rotational symmetric AF fluctuations change into FM spin fluctuations above T N. These results suggest that the first-order AF phase transition in FePSe3 may arise from the competition between C 3 symmetric AF and C 1 symmetric FM spin fluctuations around T N, in place of a conventional second-order AF phase transition.
- Published
- 2024
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