Conductivity of La0.7Sr0.3MnO3 − δ films with small deviations from stoichiometry with respect to oxygen

We have studied the dynamics of the transport and optical characteristics of epitaxial La 0.7 Sr 0.3 MnO 3 − δ (LSMO) films with oxygen deficiency varied in the course of a multistage annealing. A hierarchical scheme for evaluating the defectness of the film material is proposed, which is based on the results of measurements of the minimum dc conductivity (σ dc ( T )) and the range of its variation with the temperature. It is established that the optical conductivity (σ opt ) at a radiation quantum energy of 2 eV corresponds to the limiting value of minimum σ dc ( T ) in LSMO films without oxygen deficiency. This result does not contradict previously reported optical data and is consistent with the existing notions about the mechanisms of conductivity operative in the system under consideration.