Evaluation of the switching rate for magnetic nanoparticles: Analysis, optimization, and comparison of various numerical simulation algorithms

Here, the authors address one of the most important problems of statistical physics in magnetism -- evaluation of the escape rate over high energy barriers -- using the archetypal example of a biaxial macrospin. After deriving an analytical expression for the corresponding rate, predictions of two analytical and four numerical methods for the switching time dependence on the barrier height in the range 10--60 kT (so that the switching time spans 20 orders of magnitude) are compared. It is shown that for large barriers only the forward flux method provides physically reasonable results.