Anomalous electron structure and magnetic properties in copper doped sulphur spinel

Abstract The Jahn–Teller distortional spinel compounds Fe 1− x Cu x Cr 2 S 4 ( x = 0.1 , 0.5) with conduction mechanism are investigated. The Mossbauer spectra were recorded from 13 K to room temperature. The asymmetric line broadening was observed for the x = 0.1 and considered to be the dynamic Jahn–Teller distortion. The unusual reduction of magnetic hyperfine field below 100 K may be explained in terms of cancellation effect between the mutually opposite orbital current field ( H L ) and Fermi contact field ( H C ). Mossbauer spectra identify that Fe ions occupy tetrahedral sites, the Cr ions occupy octahedral sites with a +3 valence in the Fe 1− x Cu x Cr 2 S 4 ( x = 0.1 , 0.5). The charge state of Fe ions are ferrous (Fe 2+ ) for the x = 0.1 , while Fe ions are ferric (Fe 3+ ) for the x = 0.5 .