Physical and magnetic properties of highly anisotropic cobalt ferrite particles

Abstract Highly crystalline cobalt ferrite nanoparticles have been prepared in order to investigate the cubic anisotropy of these materials. The particles were prepared by co-precipitation and the decomposition of an organo-metallic complex. Physical characterization was carried out by TEM from which it was determined that the samples had median particle sizes between 5.1 and 12.5 nm. The crystallinity of the particles was investigated by high-resolution TEM. Magnetic measurements of remanence and coercivity as a function of temperature were carried out using vibrating sample magnetometers. Squarenesses of above 0.5 were measured at low temperatures confirming the cubic anisotropy of the materials. An anisotropy field of 1.6 T was extracted from the measurement of coercivity as a function of temperature for highly crystalline samples. The large magnetocrystalline anisotropy leads to these particles potential applications as magnetic inks and hysteresis heating for biomedical uses.