Eur. Phys. J. B (2014) 87: 133
https://doi.org/10.1140/epjb/e2014-50215-1

Regular Article

Nonlinear conductivity in CaRuO₃ thin films measured by short current pulses

¹ I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
² Experimentalphysik VI, Zentrum für Elektronische Korrelationen und Magnetismus, Universität Augsburg, 86135 Augsburg, Germany

^a e-mail: cstingl@gwdg.de

Received: 28 March 2014
Received in final form: 6 May 2014
Published online: 18 June 2014

Abstract

Metals near quantum critical points have been predicted to display universal out-of-equilibrium behaviour in the steady current-carrying state. We have studied the nonlinear conductivity of high-quality CaRuO₃ thin films with residual resistivity ratios up to 57 using microsecond-short, high-field current pulses at low temperatures. Even for our shortest pulses, Joule heating persists, making it impossible to observe an intrinsic nonlinearity. Comparing with THz spectroscopic results, we can establish a clear window for the pulse duration needed to observe the predicted universal nonlinear conductivity.