EPR study of the structural phase transitions in chromium doped thallium indium disulphide

Abstract

The results of low-temperature electron paramagnetic resonance (EPR) investigations of Cr3+ doped TlInS2 single crystals in the temperature range 5-300K are presented. Remarkable temperature dependences of the linewidth and resonance field of the main absorption peak in EPR spectra of Cr3+ ion were observed. These peculiarities are attributed to the well-known successive phase transitions between 200 and 220 K. Considerable changes of EPR spectra were observed at the temperatures below 80 K, which are associated with strong line broadening, splitting, and appearance of additional peaks. Such transformations are considered as results of tetragonal distortions of InS4 tetrahedra. An active group responsible for the previously reported phase transitions at the temperatures 216, 204 and 79 K has been determined. (C) 2002 Elsevier Science B.V. All rights reserved.