Influence of cation distribution on magnetic response of polycrystalline Co < inf > 1-x < /inf > Ni < inf > x < /inf > Fe < inf > 2 < /inf > O < inf > 4 < /inf > (0 ≤ x ≤ 1) ferrites

Abstract

The present paper reports the interconnection between cation distribution and physical properties of Co1-x Ni x Fe2O4 (0 ≤ x ≤ 1) samples to tune them for suitable applications at room temperature. A set of five Co1-x Ni x Fe2O4 (CNFO) samples with different nickel concentration (x) were prepared by using citrate-based 'sol-gel' method. The x-ray diffraction (XRD), Raman spectroscopic and scanning electron microscopic techniques were employed to characterize the samples structurally and morphologically. The Rietveld refinement of diffraction data confirms the monophasic spinel cubic structure with Fd3¯m space group. The cationic arrangement between the tetrahedral (A-) and octahedral (B-)sites of (AB2O4-type) CNFO samples was estimated from the diffraction intensities of XRD and the spectral peaks of Raman data. Based on the cation arrangement, the estimated magnetic moment values, by adopting Neel's sublattice model, were in correlation with each other and found to reduce with the rise in nickel content. A systematic change in the lattice, spectral and magnetic parameters with an increase in nickel content in CNFO, clearly ensures the transformation from hard to soft magnetic behavior of the samples. The marked magnetic transformation was elucidated in the framework of cation distribution. The tuning of magnetic parameters and cation distribution in ferrites with an appropriate element substitution might be a viable approach to make them for desired high-frequency magnetic applications.