Non-stoichiometric cobalt ferrite, CoxFe3-xO4 (x=1.0 to 2.0): Structural, magnetic and magnetoelastic properties

This work discusses the changes in the structural, magnetic and magnetoelastic properties of CoxFe3-xO4 (x=1.0 to 2.0) due to variations in cation concentration and the presence of a secondary Co1-yFeyO phase. Non-stoichiometric cobalt ferrite samples used in this study were prepared via the ceramic method. Samples with x>1 possess two phases; a secondary rock salt Co1-yFeyO phase and a spinel cobalt ferrite phase with varying cation concentration. The sample x=1 has only the spinel phase. Increase in Co concentration resulted in a decrease in magnetization but an increase in coercivity. Magnetostrictive properties and magnetocrystalline anisotropy were also affected by deviation from stoichiometric composition. Results are discussed on the basis of the coexistence of Co3+, Co2+ and Fe3+ in the spinel lattice of the samples and the influence of the secondary Co1-yFeyO phase on the overall properties. (C) 2013 Elsevier B.V. All rights reserved.