MOSSBAUER STUDY OF NI-X(CU0.5FE0.5)(1-X)CR2S4

Ni-x(Cu0.5Fe0.5)(1-x)Cr2S4 has been studied by Mossbauer spectroscopy and X-ray diffraction. The crystal is found to have a cubic spinel structure and the lattice constant decreases with increasing Ni concentration. The iron ions are in ferric states and occupy the tetrahedral sites. When the nickel concentration at the tetrahedral sites increases from 10 to 30%, magnetic hyperfie held and Neel temperature are found to decrease by 2 and 9%, respectively. As the interatomic distance decreases by 0.4%, Debye temperature increases rapidly by 37%.