Magnetic hyperthermia of laponite based ferrofluid

Magnetic Hyperthermia experiments have been performed on different concentrations of magnetic iron oxide nanoparticles immobilized on nano-clay disks. The specific absorption rate (SAR) was measured in AC field amplitudes H-0 from 7 to 30 kA/m. At low field amplitudes, SAR followed the usual H-0(2) law whereas for higher field amplitudes a linear dependence was found for the higher concentrations. Measurements at three different field amplitudes were also performed for a wide range of iron oxide concentrations in order to determine the effect of the Brownian relaxation time to SAR. A field dependent maximum was observed and for fields up to 20 kA/m the power dissipation losses were well explained according to theoretical predictions. (C) 2013 Elsevier B.V. All rights reserved.