Quasiparticle Relaxation Dynamics in Two Distinct Gap Structures: La${}_{0.67}$Ca${}_{0.33}$MnO${}_3$ and LaMnO${}_3$

Abstract

The spin and quasiparticle relaxation dynamics in La${}_{0.67}$Ca${}_{0.33}$MnO${}_3$ and LaMnO${}_3$ single crystals and thin films is investigated as a function of temperature and magnetic field by pump-probe spectroscopy. The unusually slow spin-lattice relaxation dynamics is governed by the temperature- and magnetic field- dependent pseudogap in La${}_{0.67}$Ca${}_{0.33}$MnO${}_3$, and by the temperature-independent Jahn-Teller gap in LaMnO${}_3$. Our results show that the coupled dynamics of charge, spin and lattice is strongly correlated with the distinct gap structures in these manganites.

9 pages, 4 figures