Preparation and characterization of bamboo charcoal/Ni_(0.5)Zn_(0.5)Fe_2O_4 composite with core-shell structure

摘要

Bamboo charcoal particles coated with Ni_(0.5)Zn_(0.5)Fe_2O_4, forming a core-shell structure, were synthesized by hydrothermal method. A structural characterization by FTIR, XRD and TEM proved that nanometer-sized Ni_(0.5)Zn_(0.5)Fe_2O_4 in the composite was responsible for the ferromagnetic behavior of the composite. Effects of the bamboo charcoal and temperature on the magnetic properties of bamboo charcoal/Ni_(0.5)Zn_(0.5)Fe_2O_4 composite have been studied by ferromagnetic resonance (FMR) technique. The measuring temperature was varied from 220 to 460 K. A clear evolution from ferromagnetic resonance to paramagnetic resonance (EPR) was observed as a function of temperature, which is related with the passage through the Curie point (~380 K).