Polymer Assisted Co-precipitation Synthesis and Characterization of Polyethylene Glycol (PEG)/CoFe_2O_4 Nanocomposite

摘要

Polyetylene glycol (PEG)/CoFe_2O_4 nanocomposite have been synthesized by PEG assisted co-precipitation method. The presence of PEG on the surface of CoFe_2O_4 nanoparticles was confirmed by Fourier transform infrared spectroscopy. Vibrating sample magnetometer measurements revealed a saturation magnetisation (M_s) value of 90.95 emu/g, which is higher than bulk value, and coercive field (H_s) of 862 Oe that is close to the bulk value at room temperature. The temperature dependent magnetization increases initially and then decreases with increasing temperature. This anomality is attributed to the decrease of B sublattice magnetization more rapidly than A sublattice magnetization. The M_r/M_s values lower than theoretical value of 0.5 suggests that the PEG/CoFe_2O_4 nanocomposite has effective uniaxial anisotropy according to the Stoner-Wohlfarth model. Enhanced magnetic properties (higher M_s and bulk-like H_c value) make the PEG/ CoFe_2O_4 nanocomposite a promising candidate for high density magnetic recording media.