Role of photoinduced heating in transient photoconductivity in CMR materials

The temperature dependence of the photoconductivity of La1−xSrxMnO3 colossal magnetoresistance (CMR) films and single crystals has been studied using visible pulsed radiation. The responses in films and crystals have similar appearance but are in different time scales. Critical reduction of the relaxation rate was observed in vicinity of the transition temperature. The experimental results are explained with a simple thermodynamic model accounting for the latent heat of ferromagnetic transition as well as heat conduction and redistribution processes.