Picosecond time-resolved magnetization reversal dynamics in Ni80Fe20 microstructure

Ultrafast magnetization reversal dynamics in a 15-nm-thick Ni80Fe20 microst ructure (10 mum x 2 mum) is studied using both time-resolved scanning Kerr microscopy and numerical simulation. The time dependence of the magnetizati on component along the magnetic easy axis reveals a dramatic reduction in s witching time, when the magnetization vector is pulsed by a longitudinal sw itching field while a steady transverse biasing field is applied. According to the time domain images, the abrupt change of the switching time is due to the change in the magnetization reversal mode; i.e., the nucleation domi nant reversal process is replaced by domain wall motion if a transverse bia sing field is applied. (C) 2001 American Institute of Physics.