Abstract
The strongly damping-dependent nonlinear dynamical response of classical superparamagnets is investigated by means of an analytical approach. Using rigorous balance equations for the spin occupation numbers a simple approximate expression is derived for the nonlinear susceptibility. The results are in good agreement with those obtained from the exact (continued-fraction) solution of the Fokker-Planck equation. The formula obtained could be of assistance in the modeling of the experimental data and the determination of the damping coefficient in superparamagnets.
- Received 31 October 2003
DOI:https://doi.org/10.1103/PhysRevB.70.064415
©2004 American Physical Society