Electric transport coefficients in highly epitaxial LaBaCo2O5 + δ films with “p-to-n” transition induced by oxygen deficiency

Electric transport coefficients such as carrier type, density, and mobility are the important physical parameters in designing functional devices. In this work, we report the study on the electric transport coefficients of the highly epitaxial LaBaCo2O5 + δ (LBCO) films, which were discussed as a function of electric conductivity for the first time and compared with the results calculated by the theory for mixed conduction. The mobility in the LBCO films was determined to be ∼0.85 and ∼40 cm2/V s for holes and electrons, respectively, and the density of p-type carriers strongly depends on the oxygen deficiency. Solid evidence is presented to demonstrate that the oxygen deficiency cannot make LBCO materials changed from p- to n-type. The n-type conduction observed in experiment is a counterfeit phenomenon caused by the deficiency in Hall measurement, rather than a realistic transition induced by oxygen deficiency. In addition, the temperature-dependent conductivity was discussed using the differential coefficients, which might be useful in the study of the samples with magnetic transition.