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

摘要

The results of low temperature electron paramagnetic resonance (EPR) study of Fe doped TlGaS2 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 Fe3+ centers located at the centers of GaS4 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 TlGaS2. On comparing the EPR spectra of Fe3+ centers in TlGaSe2, 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.