Stretched-exponential decay in isolated single domain particles

We analyze here a semi-analytic expression for the decay law of a uniaxial single domain particle. Coherent rotation of magnetization, axial symmetry and constant applied field are assumed. The observed decay is determined by a competition between local equilibrization and overbarrier processes, and deviations from exponential decay occur if these two processes take place on a comparable time scale. The relative timescales are shown to depend not only on applied field and temperature, but also very strongly on the initial state of the particle.