  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 [P. F. de Chatel, I. Nandori, J. Hakl, S. Meszaros and K. Vad, J. Phys.:
Condens. Matter 21, 124202 (2009)]. As opposed to many applications 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 when only
dynamical effects are taken into account. Thus, in this case, 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.
