High temperature magnetic properties of cobalt ferrite nanoparticles

摘要

Cobalt ferrite materials have a wide variety of technological applications that requires temperatures higher than room temperature. Thus the magnetic properties such as saturation magnetization, M_s remanent magnetization, M_r, coercivitty, H_c, and Curie temperature, T_c, of nanoparticles of CoFe_2O_4 were studied in a broad range of temperature varying from room temperature to 870 K. It was observed that, for temperatures 100 K above room temperature, these magnetic properties are still the same as at room temperature. The results were discussed in terms of interparticle interactions induced by the thermal fluctuations, cation distribution, and other imperfections that exert fields on Co~(2+) ions could increase with temperature.