A new semimagnetic compound: Cd1-xFexIn2S4 single crystal grown by CVT

Single crystals of the Cd1-xFexIn2S4 compounds were grown by the chemical vapour transport method using iodine as transport agent. The crystals were grown by placing the ampoule in a two zone furnace, keeping the source temperature and the deposition temperature at 850 and 800 °C respectively. The resulting crystals with nominal concentrations: x = 0.25, 0.5, 0.75 were characterized by X-ray powder diffraction, electron probe micro-analysis and magnetic measurements. Electron probe micro-analysis showed that the actual concentration of Fe was lower than the nominal one. X-ray diffractograms were taken at room temperature for each sample, revealing that the compounds form a solid solution in the whole range of compositions and crystallize with cubic symmetry in the space group Fd3m. All samples show a spinel structure with a random arrangement of cations. The magnetic behavior of the samples was investigated by low-field magnetization measurements in the range 5-300 K. The observed magnetic behavior does not show any magnetic transition in the studied temperature range. However an irreversibility has been observed between zero-field-cooled (ZFC) and field-cooled (FC) cycles. High temperature susceptibility data follow the Curie-Weiss law with a negative paramagnetic Curie temperature, indicating the predominance of antiferromagnetic interactions. The optical absorption data for sample with x = 0.75 shows a direct energy gap of 1.28 eV at RT.