Nonlinear conductivity in CaRuO3 thin films measured by short current   pulses
  Metals near quantum critical points have been predicted to display universal out-of equilibrium behavior in the steady current-carrying state. We have studied the non-linear conductivity of high-quality CaRuO$_3$ thin films with residual resistivity ratio up to 57 using micro-second short, high-field current pulses at low temperatures. Even for the shortest pulses of $5\mu$s, Joule heating persists, making it impossible to observe a possible universal non-linearity. Much shorter pulses are needed for the investigation of universal non-linear conductivity. 
Sven Esser, Sebastian Esser, Christian Stingl, Philipp Gegenwart
cond-mat.mtrl-sci cond-mat.str-el