Dynamics of photoinduced melting of charge/orbital order in a layered manganite La0.5Sr1.5MnO4 -: art. no. 113105

Photoinduced effects on the charge- and orbital-ordered (CO/OO) states in a layered perovskite manganite La0.5Sr1.5MnO4 have been investigated with femtosecond polarization-sensitive pump-probe spectroscopy. Disappearance of the optical birefringence as well as conspicuous change of the optical:spectrum indicates the immediate destruction of the CO/OO states upon photoexcitation. A large difference in the temporal evolution of the birefringence and the reflectivity change was observed, indicating that the adiabatic, fast (<200 fs) photomelting of the CO/OO states is followed by slow (10 ps-10 ns) evolution of the lattice disorder, which is subject to the critical slowing down effect as the temperature approaches T-CO = 220 K.