Synthesis and characterization of cobalt ferrite powdered materials

Abstract

The thesis dealt with the effects of various factors on the magnetic properties, especially coercivity of cobalt ferrite (CoFe2O4) powdered materials. The experimental results revealed the strong dependence of magnetic properties on the average particle size and size distribution as well as cation distribution of the resultant powders. Ni2+ substitution of Co2+ in NixCo1-xFe2O4 samples revealed the effects of chemical composition, and the key role of Co2+ in the intrinsic magnetocrystalline anisotropy of cobalt ferrite materials. Mechanical milling induced high coercivities up to 5.1 kOe in CoFe2O4 and NixCo1-xFe2O4 samples. Microstructure analysis and detailed magnetic studies revealed the domain-wall pinning mechanism and stress anisotropy for the milled-induced high coercivities in CoFe2O4 and NixCo1-xFe2O4 samples.