  The physics of magnetic state change or reversal in single domain magnetic
grains (called Stoner particles) is interesting from the fundamental as well as
the applied points of view. A change in magnetization can be finely tuned with
a specific time variation o f an externally applied magnetic field. It may also
occur naturally (without application of a field) at very low tempe rature with
quantum tunneling and at higher temperature with thermal excitation. The
optimal (usually shortest) time altering the magn etisation along with the
smallest applied magnetic field are sought in technological applications s uch
as high-density reading or writing of information, spintronics, quantum inform
ation and quantum communication systems. This work reviews the magnetization
change with a time dependent field and tem perature and discusses the time it
takes to alter the magnetization as a function of the control parameter chosen,
temperature and material parameters.
