Structural, dielectric and magnetic properties of cobalt ferrite prepared using auto combustion and ceramic route

Cobalt ferrite is synthesized by using low temperature auto combustion and high temperature ceramic methods. The prepared samples have values of lattice constant equal to 8.40Å and 8.38Å for auto combustion and ceramic methods respectively. The FTIR spectrum of samples of the auto combustion method shows a high frequency vibrational band at 580cm−1 assigned to tetrahedral site and a low frequency vibrational band at 409cm−1 assigned to octahedral site which are shifted to 590cm−1 and 412cm−1 for the ceramic method sample. SEM micrographs of samples show a substantial difference in surface morphology and size of the grains between the two methods. The frequency dependent dielectric constant and ac conductivity of the samples measured from 1Hz to 2MHz at room temperature are reported. The room temperature magnetic hysteresis parameters of the samples are measured using VSM. The measured values of saturation magnetization, coercivity and remanent magnetization are 42emu/g, 1553Oe, 18.5emu/g for the auto combustion method, 66.7emu/g, 379.6Oe, and 17.3emu/g for the ceramic method, respectively. The difference in preparation methods and size of the grains causes interesting changes in electrical and magnetic properties.