Femtomagnetism is recently emerged field in condensed matter physics focused at searching novel fundamental mechanisms of manipulating magnetic state by femtosecond laser pulses. One of the promising materials for femtomagnetism are ferrimagnetic garnets due to the possibility of controlling their anisotropy on a picoseconds timescale. In this work we studied the laser-induced magnetization dynamics in substituted garnet films characterized by pronounced out-of-plane anisotropy. Using magneto-optical pump-probe technique we’ve demonstrated two different types of laser-induced magnetization dynamics in garnet films. Depending on magnetic anisotropy strength we observed either laser-induced demagnetization occurring due to spin temperature increase or magnetization precession induced by fast change in the magnetocrystalline anisotropy.
This work is supported by the Russian Government Program P220 (Grant #14.B25.31.0025) and in part by the RFBR (Grant #13-02-00754).