Electrical transport properties of V3Si, V5Si3, and VSi2 thin films

Abstract

Resistivity measurements in a wide temperature range (2–1100 K) have been performed on thin films of ${\mathrm{V}}_3$Si, ${\mathrm{V}}_5$ ${\mathrm{Si}}_3$, and ${\mathrm{VSi}}_2$ formed on an inert substrate. An anomalous resistivity behavior has been observed in these metallic compounds: The resistivity deviates from linearity and approaches a saturation value at the higher temperatures. The resistivity data can be fitted quite well to a phenomenological expression based on the idea that a limiting resistivity is reached when the electron mean free path is of the order of the interatomic spacing. The electron mean free paths, which have been computed from the experimental data, lend support to the above idea. The saturation phenomenon in ${\mathrm{V}}_3$Si and ${\mathrm{V}}_5$ ${\mathrm{Si}}_3$ compounds is characterized by a limiting resistivity of the same magnitude as observed in several A15 materials and in the Mooij correlation, yet in ${\mathrm{VSi}}_2$ the resistivity saturates to a much higher value. The ${\mathrm{V}}_3$Si is a superconductor with a transition temperature around 15 K and a residual resistivity ratio of 10.6. On the other hand, ${\mathrm{V}}_5$ ${\mathrm{Si}}_3$ and ${\mathrm{VSi}}_2$ thin compound films do not show superconductivity state down to 2 K. The temperature dependence of the Hall coefficient gives evidence of a complex and different electronic structure of the three compounds.