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 Tmin 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.