Self-heating characteristics of cobalt ferrite nanoparticles for hyperthermia application

The self-heating temperature rising characteristics of CoFe2O4 hard spinel ferrite nanoparticles were investigated and were compared to those of soft spinel ferrite in order to explore the effects of magnetic anisotropy and magnetic susceptibility on the behavior of self-heating temperature rising characteristics for hyperthermia application. The maximum self-heating temperature, elevated by using our specially designed RF-MRI modified LC circuit in a solid state, was 4.6 degrees C. The corresponding frequency and magnetic field strength product for the 4.6 degrees C temperature rising, H(0)f, was 13.4 x 10(8) Am-1 s(-1). The extremely low elevated temperature and the small specific absorption rate (SAR) relevant to the gentle slope from the time vs. temperature rising curve were found to be primarily due to a stronger anisotropy (or a smaller magnetic susceptibility) of CoFe2O4 hard spinel ferrite nanoparticles compared to the soft spinel ferrite nanoparticles. (C) 2006 Elsevier B.V. All rights reserved.