Quasiparticle Relaxation Dynamics in Two Distinct Gap Structures: La 0.67 Ca 0.33 MnO 3 and LaMnO 3
Y. H. Ren, H. B. Zhao, G. L\U{fc}pke, Y. F. Hu, Qi Li, C. S. Hong, N. H. Hur
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.