Electron transport in NiCr-O thin films at low temperatures

Abstract
Starting from measurements of the DC conductivity sigma (T) in the temperature range from 0.05 to 300 K, the authors can qualitatively describe the electron transport in NiCr-O thin films at low temperatures by its dependence on the atomic oxygen concentration cO. At a critical value of cO a metal-insulator transition occurs near T=0. In the metallic region the electrical behaviour can be interpreted in terms of weakly localised electrons including electron correlation. In the non-metallic region an activated temperature dependence is found which is due to variable-range hopping of strongly localised electrons.