Thermal switching rate of a ferromagnetic material with uniaxial   anisotropy
  The field dependence of the thermal switching rate of a ferromagnetic material with uniaxial anisotropy was studied by solving the Fokker-Planck equation. We derived the analytical expression of the thermal switching rate using the mean first-passage time approach, and found that Brown's formula [Phys. Rev. 130, 1677 (1963)] is applicable even in the low barrier limit by replacing the attempt frequency with the proper factor which is expressed by the error function. 
Tomohiro Taniguchi and Hiroshi Imamura
cond-mat.mes-hall