Magnetoresistance and non-Ohmic conductivity of thin platinum films at low temperatures

Abstract

The electrical conductivity of thin Pt films is measured as a function of temperature T, magnetic field B, and electric field E. A logarithmic temperature dependence is observed. The magnetoresistance is positive and anisotropic, increasing as B2/T in small perpendicular fields and logarithmically in high B⊥. The electric field causes the resistance to drop proportional to E2 at low E and logarithmically at high E, in agreement with localization theory. Our data on the magnetoresistance, however, disagree with theory.