Particle Size Dependent Structural and Magnetic Properties of Cocrfeo_4 Nanoparticles

摘要

Nanoparticles of CoCrFeCU ferrite in the particle size range of 9 - 38 nm have been prepared by a sol-gel auto combustion method. Synthesized powders were annealed at four different temperatures viz. 400 °C, 600 °C, 800 °C and 1000 °C. Particle sizes are determined by X-ray analysis and TEM. The size of the nanoparticles increase linearly with sintering temperature and time, most probably due to coalescence that increases as sintering temperature increases. The saturation magnetization increases from 62 to 81 emu/g and coercivity initially increases up to 814 Oe and then decreases to 366 Oe with increase in particle size and sintering temperature. The typical blocking temperature increases from 135 to 165 K with increasing particle size.