Magnetic properties of CoFe2O4 synthesized by solid state, citrate precursor and polymerized complex methods: A comparative study

CoFe2O4 ferrite was synthesized by solid state, citrate gel precursor and polymerized complex methods. Both the solid state method and the polymerized complex method at high temperatures produced micron-sized cobalt ferrite particles. Citrate precursor method and polymerized complex method at low temperatures produced nanosized particles. Using these three techniques, particle size in the range of 30–530 nm could be obtained. Magnetic properties of these samples were found to depend strongly on the particle size. Saturation magnetization was found to decrease marginally with increase in particle size whereas the coercively was found to increase exponentially from 219 Oe to 1625 Oe as the particle size was reduced from 530 nm to about 30 nm. The variations in the magnetic properties are attributed to the grain size effects and cation redistribution. The present work shows that magnetic properties could be tuned over a wide range, by changing the synthesis conditions.