Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication
Spin-triplet excitons in the S = 1/2 gapped antiferromagnet BaCuSi2O6: Electron paramagnetic resonance studies
Zvyagin, S. A.; Wosnitza, J.; Krzystek, J.; Stern, R.; Jaime, M.; Sasago, Y.; Uchinokura, K.;
BaCuSi2O6, a S = 1/2 quantum antiferromagnet with a double-layer structure of Cu2+ ions in a distorted planar-rectangular coordination and with a dimerized spin singlet ground state, has been studied by means of the electron paramagnetic resonance technique. It is argued that multiple absorptions observed at low temperatures are intimately related to a thermally activated spin-triplet exciton superstructure, which appears to be a characteristic feature of low-dimensional anisotropic spin- 1/2 systems with the dimerized spin-singlet ground state. We showed that analysis of the angular dependence of exciton modes could be used for accurate estimation of anisotropy parameters in BaCuSi2O6; the procedure can be applied for a large number of S = 1/2 quantum antiferromagnets. In addition, the temperature dependence of EPR intensity and linewidth in BaCuSi2O6 has been studied and discussed.

Publ.-Id: 9150 - Permalink