CRYSTALLOGRAPHIC AND MAGNETIC-PROPERTIES OF CUIN0.1FE1.9O4

CuIn0.1Fe1.9O4 has been studied by Mossbauer spectroscopy and X-ray di ffraction. The crystal is found to have a cubic spinel structure with the lattice constant a0 = 8275 +/- 0.005 angstrom. It is noteworthy th at the 5% replacement of Fe by In in the copper ferrite transforms the crystal structure from a tetragonal to a cubic structure and decrease s the quadrupole shifts drastically. The iron ions at both A (tetrahed ral) and B a cubic (octahedral) sites are found to be in ferric states . Atomic migration from A to B sites starts near 250 K and increases r apidly with increasing temperature to such a degree that 87% of the fe rric ions at the A sites move over to the B sites at