Magnetic hyperthermia for treatment of tumors would benefit greatly from increased heating of the superparamagnetic particles, coupled with reduced incident electromagnetic wave power. Previous micromagnetic simulations based on the Landau-Lifshitz-Gilbert equation with thermal fluctuations showed that the use of incident square waves greatly increases the normalized heat. Experimentally generating a square waveform may produce a trapezoidal waveform due to an inherent rise and fall time. It is found that the normalized heating power given by this wave shows a 30% improvement over the sinusoidal waveform for an anisotropy distribution of 20%. A static magnetic field can increase the effectiveness of a sinusoidal waveform, but gives little added benefit to the effectiveness of a square waveform.
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This work was supported by National Science Foundation contract BME 0730825.