Title: 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 $\frac{{B}^{2}}{T}$ in small perpendicular fields and logarithmically in high ${B}_{\ensuremath{\perp}}$. The electric field causes the resistance to drop proportional to ${E}^{2}$ at low $E$ and logarithmically at high $E$, in agreement with localization theory. Our data on the magnetoresistance, however, disagree with theory.