Resistivity of AlNi Nanosized Alloy Film at Low Temperature

AlNi films were grown by magnetron sputtering and the change rule of film resistivity with temperature (8-300 K) was measured by self-made straight four-probe low temperature measurement system. It is found that the resistivity of pure Al and Ni nano films exhibits a positive resistivity temperature coefficient due to the electron phonon or electron-magnetron interaction. Moreover, the electron-magnetron scattering plays a much important role at high temperature region (80-300 K), while the grain boundary/surface has a dominant effect on the resistivity of pure metal films at low temperature region (<40 K). With increasing the amount of Ni atoms doping into the films, Al_1-xNi_x nano-alloy films gradually transfer from the crystalline-metal phase to semiconductor one with a negative resistivity temperature coefficient. At low temperatures, the electrons are excited from one localize state to another one with the help of phonons. Due to the low-dimensional localization effect, the resistivity-temperature relationship of the Al_1-xNi_x nano-alloy films follows no longer completely the thermally activated conductive model, but also partially the polarization mechanism.