Understanding high-field amplitude electromagnetic heat loss phenomena is of great importance, in particular, in the biomedical field, because the heat-delivery treatment plans might rely on analytical models that are only valid at low field amplitudes. Here, we develop a nonlinear response model valid for single-domain nanoparticles of larger particle sizes and higher field amplitudes in comparison to the linear response theory. A nonlinear magnetization expression and a generalized heat loss power equation are obtained and compared with the exact solution of the stochastic Landau-Lifshitz-Gilbert equation assuming the giant-spin hypothesis. The model is valid within the hyperthermia therapeutic window and predicts a shift of optimum particle size and distinct heat loss field amplitude exponents, which is often obtained experimentally using a phenomenological allometric function. Experimental hyperthermia data with distinct ferrite-based nanoparticles and third harmonic magnetization data support the nonlinear model, which also has implications for magnetic particle imaging and magnetic thermometry.
Giant-spin nonlinear response theory of magnetic nanoparticle hyperthermia: A field dependence study
M. S. Carrião, V. R. R. Aquino, G. T. Landi, E. L. Verde, M. H. Sousa, A. F. Bakuzis; Giant-spin nonlinear response theory of magnetic nanoparticle hyperthermia: A field dependence study. J. Appl. Phys. 7 May 2017; 121 (17): 173901. https://doi.org/10.1063/1.4982357
Download citation file: