Inversion of the temperature coefficient of resistance of chromium films as the result of their nanocrystalline structure

The temperature dependence of the resistance of chromium films obtained by the thermal deposition on a substrate at room temperature was studied. It is shown that the most probable crystallite size in as-deposited films is 9 nm and increases by about 15% after the first annealing. According to the results of resistive studies, the structure formed after the first heating is stable and changes slightly during thermal cycling. It has been found that up to a temperature of approximately 200 °C, the temperature coefficient of resistance of the samples is negative and amounts to approximately −2 · 10−4 K−1. With a further increase in temperature, the temperature coefficient of resistance becomes positive, but remains significantly lower than the value corresponding to chromium in the bulk state. The observed effects are explained by the nanocrystalline structure of the samples.