Nanoscale current modulations in Pr0.7Ca0.3MnO3 thin films

Many theoretical and experimental efforts have been focused on the origin of the electric-pulse-induced resistance change effect. However, there are still various reports of the origin supporting either the bulk nature or the interface nature. To resolve the controversies, nanoscale electronic measurements may provide essential clues. In this work, we report microscopic electrical properties of Pr0.7Ca0.3MnO3 thin films. The resistance of a single-crystalline grain is not homogeneous in nanometer scale. We deduce that nanoscale inhomogeneity is related to the periodic relaxation of substrate-induced strain, which is caused by the lattice mismatch between the substrate and the thin film.