Effect of Annealing Temperature and Preparation Condition on Magnetic Anisotropy in Nanocrystalline Cobalt Ferrite.

Nanocrystalline cobalt ferrite (\CoFe2{\O}4) materials have been synthesized by citrate precursor and co-precipitation method. Samples are annealed at different temperatures to obtain the different nanocrystallite-size materials. All the samples crystallize to Fd\overline3m space group in cubic symmetry. Magnetic hysteresis loops measurement has been carried out at room temperature using a vibrating sample magnetometer (VSM). The magnetic data in the saturation region have been analyzed by employing the law of approach (LA) to saturation technique. The anisotropy constant ( K1) is found to be higher in citrate precursor derived samples. The saturation magnetization ( Ms), coercivity ( Hc), remanent magnetization ( Mr) and anisotropy constant ( K1) increases with the increase of crystallite size. [ABSTRACT FROM AUTHOR]