Magnetization and self-heating temperature of NiFe2O4 nanoparticles measured by applying ac magnetic field

Abstract

Magnetic and self-heating properties of various size NiFe2O 4 (7.7-242.0 nm) were evaluated. The self heating temperature of each sample measured by applying ac magnetic field was affected by its magnetic property. The particle size dependence was also explained by the magnetic properties of the samples. At the lower frequency, the self heating was contributed by hysteresis loss. The ac magnetization process was also evaluated and the result could clarify the origin of self-heating. The 7.7 nm particle was heated by relaxation losses by the applied field at higher frequency. The energy efficiency of a magnetic field to generate self heating was analyzed. It was found that the particle of 130.7 nm exhibited the highest temperature rise and heat generation efficiency for the applied field of low amplitude and frequency. © 2010 IOP Publishing Ltd.