Control of Coercivity and Magnetic Anisotropy Through Cobalt Substitution in Ni-Zn Ferrite

The present study aims to develop low magnetic anisotropy Ni-Zn nanoferrites with cobalt substitution. The results enable the development of nanoferrite samples with superior magnetic properties suitable for high-frequency core applications through an understanding of the influence of cobalt in the manipulation of the magnetic anisotropy of the nanoferrite. Ni0.65-xZn0.35CoxFe2O4 (x varies from 0.00 to 0.24 in steps of 0.04) particles were synthesized by sol-gel method using polyvinyl alcohol as a chelating agent. X-ray diffraction patterns of all the samples showed sharp peaks corresponding to spinel structure with no extra phases. Transmission electron micrographs depict uniform size distribution of particles in the range 185 to 247 nm. Magnetic properties were measured at 300 K and 5 K. Excellent control to reduce the magnetic anisotropy to a negligible amount can be achieved by incorporating minute amounts of cobalt in nickel-zinc ferrite.