Synthesis of magnetite nanoparticles for AC magnetic heating

Magnetite particles with different average diameter (D-m) suitable for magnetic fluid hyperthermia (MFH) were synthesized by controlled coprecipitation technique. In this method, the reaction pH was stabilized using the pH buffer and the average particle diameter decreased with increasing reaction pH. The size-dependent magnetic behaviour of the magnetite nanoparticles was studied and the optimum size range required for magnetic fluid hyperthermia (MFH) has been arrived at. Among the samples studied, the maximum specific absorption rate of 15.7 W/g was recorded for the magnetite sample with D-m of 13 nm, when exposed to an AC magnetic field strength of 3.2 kA/m and frequency of 600 kHz. The AC magnetic properties suggested that the size distribution of the sample was bimodal with average particle size less than similar to 13 nm. (C) 2009 Elsevier B.V. All rights reserved.