Ultrafast spin spectroscopy by impulsive terahertz pulse excitations
Abstract
Terahertz pulses with the magnetic field components can excite directly and control the magnetization and spin precessions in magnetic materials. Macroscopic magnetization control is successfully demonstrated by using terahertz pulse excitations around the spin reorientation phase transition. The ultrafast response of the magnetizations for nano-magnet epsilon type ferrite shows ultrafast build up and decay of sub-picoseconds which corresponds to time duration of the terahertz excitation pulses.