Fast switching of magnetic nanoparticles: simulation of thermal noise effects using the Langevin dynamics

摘要

The most straightforward method to simulate fast switching in magnetic systems is the so called Langevin dynamics, where the stochastic equations of motion for magnetic moments are solved. Thermal fluctuations are taken into account using the so called fluctuation (random) field H{sup}(fl) which is added to the standard deterministic effective field H{sup}(det). Two important methodical problems do exist when applying this formalism: (i) which interpretation of the stochastic differential equations (Ito or Stratonovich) should be used to obtain physically correct results and (ii) how to chose the correlation properties of the random field H{sup}(fl).