Effect of cobalt‐ferrite epitaxial layer on the coercivity of ZnFe‐ferrite particles (abstract)

Zn0.2Fe2.8O4 particles were prepared and coated with different amounts of cobalt‐ferrite. The coercivity increases with increasing cobalt‐ferrite coating. In the low Co‐ferrite coating regime, the increase is induced by an enhanced anisotropy of the interface layer, while in the high coating regime, it is due to the Co‐ferrite surface layer. The full depth of the interface layer was found to be approximately 8 A, and the temperature dependence of the change in coercivity in both low and high Co‐ferrite coating regimes was discussed. Mechanisms leading to a greatly increased coercivity of acicular Co‐γ‐Fe2O3 were also discussed.