Intrinsic and precipitate-induced quantum corrections to conductivity in La2/3Sr1/3MnO3 thin films

The low-temperature magnetotransport properties of manganite thin films are characterized by the occurrence of resistivity minima,. rho(min), below 30 K whose origin and especially role of disorder has not yet been explored in detail. In order to contribute to the clarification of the physical mechanism giving rise to the resistivity minimum in these systems, an appropriate concentration (3%, 6%, and 20%) of nanoscaled nonmagnetic ZrO2 particles are introduced as a secondary phase into La2/3Sr1/3MnO3 thin films. As the volume density of ZrO2 precipitates increases, the films show a more pronounced resistivity upturn for T < T-min. The measured temperature and magnetic field dependence of the resistivity of our samples is in good agreement with a combination of the theory of three-dimensional weak localization and electron-electron interactions. We show that within this frame the observed features of the scattering-related resistivity minimum at low temperature in correlated electron systems can be explained, including its spin dependence, its scattering parameters, and its variation with increasing nonmagnetic disorder.