On the origin of the low temperatures resistivity minimum in Cr thin films

Abstract

We present measurements of the electrical resistivity and Hall coefficient, ρ and RH, in Cr films of different thicknesses grown on MgO (100) substrates, as a function of temperature T and applied magnetic field H. The results show a low temperature minimum in ρ(T), which is thickness dependent. From 40 K to 2 K, the Hall coefficient is a monotonous increasing function as T is reduced with no particular signature at the temperature T min where the minimum develops. We explain the resistivity minimum assuming an imperfect nesting of the Fermi surface leading to small electron and hole pockets. We introduce a phenomenological model which supports this simple physical picture.