MOSSBAUER STUDY OF ANTIFERROMAGNETIC CUFES2-XSEX

CuFeS2-xSex has been studied by Mossbauer spectroscopy and x-ray diffraction. The crystal is found to have a tetragonal structure and the lattice constants a0 and c0 increase linearly with increasing selenium concentration. It is noteworthy that the replacement of S by Se in the chalcopyrite decreases the strength of both the superexchange interaction and the interatomic binding. As the interatomic distance increases by 1%, the magnetic hyperfine field and the Debye temperature decrease by 0.8 and 6 %, respectively. The iron ions are found to be in ferric states.