Cation distribution and magnetic interactions in Zn-substituted CuFe2O4 ferrites

A series of Cu1-xZnxFe2O4, spinel ferrites with x=0, 0.25, 0.50, 0.75 and 1.0, respectively were prepared by standard ceramic method to study the relationship between structural parameters and concentration of the substituted non-magnetic (Zn) ion. Determination of crystal structure oxygen positional parameter and cation distribution using X-ray diffraction (XRD) and R-factor method revealed that these ferrites belong to the family of mixed or partially inverse spinels. The magnetic interaction has been calculated from ac susceptibility measurements using mutual inductance technique as a function of concentration of the substituted ions in these mixed ferrites. The dominant interaction in all ferrite samples is A-B interaction which is due to the negative values of paramagnetic Curie temperature theta (K) and the distribution of cations among A and B sites showing that the magnetic ordering is antiferromagnetic. The Curie temperature (T-c) rises up to x=0.75 possibly due to increase in exchange interaction and magnetic moments. For x>0.75, T-c decreases due to cation distribution (normal) on A and B-sites resulting in the weakening of A-B interaction due to the presence of triangular spin arrangement of Y-K type on B-sublattice. (C) 2000 Elsevier Science S.A. All rights reserved.