| In this work, we study the electronic properties of La0.5Sr 0.5MnO3 (LSM5) thin films. We began the study of the electronic conductivity of LSM5 film at high temperature. The conductivity increases with temperature until it reaches a maximum, and decreases after this point. Secondly, the thermal behavior of the conductivity in thin films does not correspond to that in the bulk. In fact, conductivity in bulk material decreases with rising temperature.; With the thermal behavior of the conductivity measured at low temperature, the results obtained become more understandable. At very low temperature, conductivity decreases with temperature to reach a minimum near room temperature, and then increases. We have shown that the charge carriers in LSM5 are small polarons which move adiabaticly. In addition to the confirmation of the polaronic behavior, low temperature conductivity measurements permit one to deduce certain physical parameters which are compatible with these obtained from the high temperature conductivity analysis. (Abstract shortened by UMI.)... |
