Abstract
In the thesis, we have investigated the carrier dynamics in films of colossal magnetoresistance (CMR,La0.7Sr0.3MnO3) .First,we have measured the transmission THz time domain spectroscopy to obtain index of refract、power absorption，dielectric constant of the CMR film and then used Drude Model to estimate conductivity of the film. From these data, the index of refract of colossal magnetoresistance film in THz range (0.1~ 1.8 THz)is determined in the range of 15~65 . To understand the dynamic behaviors, we have measured time-resolved photoreflecitivity (PR) and optical pump-THz probe (OPTP) of the film .By using three temperature model to analysis these results, we can obtain the dynamics process of electron-electron interactions、electron-lattice interactions and spin-lattice interactions .From these PR data, we find five relaxation times and we can explain three of them . Similarly, from these OPTP datum we observe similar phenomenon.