Mossbauer and DC electrical resistivity study of Zn substituted tetragonal CuFe2-yGayO4 compound

Mossbauer technique has been employed for the study of hyperfine parameters of the compound Cu1-xZnxGay-Fe2-y O-4 with x from 0.0 to 0.5, and y = 0.3 in order to determine the cation inter-site distribution and establish the conduction mechanism. Substitution of Ga3+ and Zn2+ ions results in a decrease of the hyperfine field at octahedral B-sites as well as tetrahedral A-sites. The area ratio of Fe3+ ions at A- and B-sites at 77 K indicates that Zn2+ ions occupy the tetrahedral A-site where, Cu2+, and Ga3+ ions occupy the octahedral B-site. DC electrical resistivity measurements carried out on the studied samples indicate a semiconducting behavior. The magnetic transition temperature T, determined from the relation of resistivity (p) with temperature was found to decrease linearly with increasing Zn content. The activation energies calculated at the magnetic and paramagnetic regions are found to increase with increasing Zn content. The obtained results for the Mossbauer parameters are interpreted based on the superexchange and supertransferred hyperfine interactions, where results of resistivity are explained in light of the hopping conduction occurring at the octahedral B-sites. (C) 2004 Elsevier B.V. All rights reserved.