Low temperature EPR spectra of Fe3+ centers in ternary layered TlGaS2 crystal

Abstract

The results of low temperature electron paramagnetic resonance (EPR) study of Fe doped TlGaS(2) single crystal in the temperature range of 5-300 K are presented. Iron was added to the growth mixture in amounts corresponding to a molar ratio Fe/Ga of about 1%. The EPR signal due to Fe(3+) centers located at the centers of GaS(4) tetrahedrons has been observed. A transformation of EPR spectra has been observed on decreasing the temperature, which is attributed to lowering of the number of resonance lines. The simulation of rotational patterns of the resonance fields exhibits a decrease of the number of centers at low temperatures as a contrary to those of isostructural compounds of TlGaS(2). On comparing the EPR spectra of Fe(3+) centers in TlGaSe(2), it has been revealed that the Tl atoms lose their zigzag alignment observed previously at room temperature and rearranged to equal structural positions on Tl chains on lowering the temperature. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.