Effect of doping concentration on electric-pulse- induced resistance in Nd1-xSrxMnO3 ceramics

Electric-pulse-induced resistances (EPIRs) and I-V characteristics of polycrystalline Nd1-xAxMnO3 (A = Ca, Ba, Sr, x = 0-0.9) ceramics synthesized by solid state reaction are investigated. The results show that similar to Nd0.7Sr0.3MnO3, compounds Nd0.7Ba0.3MnO3 and Nd0.7Ca0.3MnO3, with the same doped concentration as that of Nd0.7Sr0.3MnO3, can also exhibit a nonlinear I-V behaviour and a stable EPIR effect at room temperature. Further studies on the Nd1-xSrxMnO3 series indicate that the stability of EPIR is closely correlated with the Sr doped concentration. Around the half doping x= 0.5, the EPIR effect can be observed stably. With Sr concentration increasing or decreasing, however, the EPIR becomes weaker gradually and disappears completely if Sr concentration further increases or decreases. The redistribution of various defects between the electrode and bulk interface with polar pulses is proposed to explain the unique transport behaviour.