Colossal electroresistance and magnetoresistance effect in polycrystalline perovskite cobaltites Nd1-xSrxCoO3 (x=0.1, 0.2, 0.3)

Polycrystalline samples of cobaltites Nd1-xSrxCoO3 (x = 0.1, 0.2, 0.3) with the perovskite structure were synthesized by conventional solid state reaction method. Different currents ranging from 1 mu A to I mA were applied to study the electroresistance (ER) effect. Temperature dependence of resistivity for the samples decrease dramatically with increase of the currents in the low temperature and non-linear current-voltage (I-V) characteristics are observed. The maximum ER ratio (defined as ER = (rho(1) (mA) - rho(L))/rho(L) x 100%) of the all samples is more than -99%, which indicates a colossal electroresistance (CER) effect has found in these compounds. What is more, we also found that electric current can have influence on the low field magnetoresistance (LFMR) of the samples. LFMR decrease with the increase of applied current. The experimental results were discussed by spin polarized carriers modified ferromagnetic (FM)/nonmagnetic (NM) interface and grain interior phase separation scenario. (C) 2012 Elsevier Ltd. All rights reserved.