Electron paramagnetic resonance investigation of Fe3+ doped TlInS2 single crystal

TlInS2 single crystal doped by paramagnetic Fe ions has been studied at room temperature by electron paramagnetic resonance (EPR) technique. The fine structure of EPR spectra of the paramagnetic Fe3+ ions is observed. The spectra were interpreted to correspond to the transitions among the spin multiplets (S=5/2, L=0) of the Fe3+ ion, which are split in the local ligand crystal field (CF) of orthorhombic symmetry. Four equivalent Fe3+ centers have been observed in the EPR spectra and the local symmetry of CF at the Fe3+ site and the CF parameters were determined. It was established that the symmetry axis of the axial component in the CF is making an angle of about 48° with the plane of layers of TlInS2 crystal. Experimental results indicate that Fe ions substitute for In ions at the center of the InS4 tetrahedrons, and the rhombic distortion of the CF is caused by Tl ions located in the trigonal cavities between the tetrahedral complexes.