EPR studies of the triangular-lattice antiferromagnet Cs2CuBr4
E. Schulze1,2, A.N. Ponomaryov1, J. Wosnitza1,2, H. Tanaka3, and S.A. Zvyagin1
1Dresden High Magnetic Field Laboratory (HLD-EMFL) Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany
2Institut für Festkörperphysik, TU Dresden, D-01069 Dresden, Germany 3Tokyo Institute of Technology, Tokyo 152-8550, Japan
Received June 19, 2017
The spin dynamics of the spin-1/2 triangular-lattice antiferromagnet Cs2CuBr4 is probed by means of high-frequency electron paramagnetic resonance (EPR) spectroscopy. Temperature dependences of EPR parameters are studied in a broad temperature range between 1.4 and 200 K for different orientations of the applied magnetic field. In the high-temperature regime (T >> J/kB), an unusually broad and anisotropic resonance line is detected, suggesting a sizeable Dzyaloshinskii–Moriya interaction. Employing the theory of exchange narrowing, the ratio of the Dzyaloshinskii–Moriya vector components, Dc/Da ≈ 0.3, is estimated.
PACS: 75.50.Ee Antiferromagnetics; PACS: 76.30.–v Electron paramagnetic resonance and relaxation; PACS: 76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance.