Electronic transport in La1.67Sr0.33NiO4 and Nd1.67Sr0.33NiO4 under high electric fields

Abstract

We report high-field conductivity measurements of polycrystalline samples of La1.67 Sr0.33 NiO4 and Nd1.67 Sr0.33 NiO4 at various temperatures in the stripe ordered state. Since their discovery, an important issue has been the response of the stripes to high electric fields. The main result of this work is that while the pulsed I-V characteristics, using single short current pulses, are ohmic for Nd1.67 Sr0.33 NiO4 up to fields of ∼550 V/ cm and ohmic or only slightly non-ohmic for La1.67 Sr0.33 NiO4 in fields of the same order of magnitude, the corresponding dc I-V characteristics are strongly nonlinear. The conditions for four-probe pulsed I-V measurements that avoid self-heating were determined experimentally. The low-field resistivity and the thermopower of our samples are in satisfactory agreement with those reported in the literature for polycrystals and for single crystals of these materials. © 2008 American Institute of Physics.