STRUCTURAL, TRANSPORT AND INFRARED STUDIES OF OXIDIC SPINELS ZN1-XNIXFECRO4

X-ray, electrical conductivity and IR studies for the system Zn1-xNixFeCrO4 were carried out. All the compounds, 0 ≤x ≤ 1 showed cubic symmetry. X-ray intensity calculations and IR studies indicate the presence of Zn2+ at tetrahedral sites, Ni2+ and Cr3+ at octahedral sites, and Fe3+ ions are equally distributed at both the sites. Activation energy and thermoelectric coefficient decreases with the increasing values of X. All the compounds exhibit P-type semiconductivity which may be due to transfer of Fe3+ ions from B-site to A-site creating holes. The electrical resistivity temperature behaviour obeys the relation ρ{variant}=ρ{variant}0 exp (ΔE/KT). The mobility of holes as calculated from IR and conductivity data is of the order of 10-9 cm2 V sec-1. The probable ionic configuration for the system is suggested to be Zn1-x2+Fex3+ [Fe1-x3+Nix2+Cr3+] O42-. © 1990 Chapman and Hall Ltd.