Abstract
, a quantum antiferromagnet with a double-layer structure of 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- 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 ; the procedure can be applied for a large number of quantum antiferromagnets. In addition, the temperature dependence of EPR intensity and linewidth in has been studied and discussed.
- Received 20 December 2005
DOI:https://doi.org/10.1103/PhysRevB.73.094446
©2006 American Physical Society