Functional characterization of SrTiO3 tunnel barriers by conducting atomic force microscopy

Electric transport through nanometric SrTiO3 layers on La0.67Ca0.33MnO3(001) epitaxial thin film electrodes has been investigated by conducting atomic force microscopy. Electrical resistance maps, recorded at various biases, of samples with barriers having different thicknesses were used to evaluate the barrier height. The method used does not require assuming a value of tip-contact area and thus allows to overcome inherent limitations of current-voltage curve analysis. The barrier height is found to be in the 0.2–0.4eV range, which is in reasonable agreement with the expected value from junction models.