Dr. Ettore Carpene:

Manipulating the spin order with ultrashort light pulses

The need for faster magnetic recording devices has driven researchers to seek more efficient ways to reverse the magnetization. A challenging task is to use ultrashort light pulses for controlling the spin order. It is shown that the magnetic vector of a thin ferromagnetic film can be optically and repeatedly commuted between well defined directions on a timescale of 100 picoseconds. Furthermore, femtosecond light pulses can alter charge distribution as well as spin order on an ultrafast timescale. Disentangling these effects is of utmost importance. We investigated the magneto-optical response of a half-metallic oxide system by time-resolved pump-probe polarimetry, showing that the diagonal (charge) and off-diagonal (spin) terms of the dielectric tensor can be unambiguously retrieved, providing a method to fully characterize the electronic and spin dynamics in correlated magnetic oxides.