Coherent Phonons in YMnO3

Strong spin-lattice coupling in multiferroic hexagonal manganite YMnO$_3$ probed by ultrafast optical spectroscopy

We report the observation of spin-lattice coupling in multiferroic YMnO$_3$ by femtosecond near-infrared pump and probe spectroscopy. A coherent 31~GHz acoustic phonon was detected above the magnetic ordering temperature, and a higher frequency coherent mode was observed in the anti-ferromagnetic phase. This temperature-dependent measurement demonstrates that the acoustic phonon excitation is coupled to spin ordering.

APPLIED PHYSICS LETTERS 97, 031914 (2010).