1206.1544 (I. Nandori et al.)

Magnetic particle hyperthermia: Neel relaxation under circularly
polarized field in anisotropic nanoparticles    [PDF]

I. Nandori, J. Racz

The deterministic Landau-Lifshitz-Gilbert equation has been used to investigate the nonlinear dynamics of magnetization and the specific loss power in magnetic nanoparticles with uniaxial anisotropy driven by a rotating magnetic field, generalizing the results obtained for the isotropic case found in [10]. As opposed to many application of magnetization reversal in single-domain ferromagnetic particles where losses must be minimized, in this paper, we study the mechanisms of dissipation used in cancer therapy by hyperthermia which requires the enhancement of energy losses. We show that for circularly polarized field, the loss energy per cycle is decreased by the anisotropy compared to the isotropic case. Thus in the low frequency limit, a better heating efficiency can be achieved for isotropic nanoparticles. The possible role of thermal fluctuations is also discussed. Results obtained are compared to experimental data.

View original: http://arxiv.org/abs/1206.1544