Influence of oxygen vacancy deep trap levels on the EPIR effect in La0.5Ca0.5MnO3 ceramics

La0.5Ca0.5MnO3 (LCMO) ceramic samples were synthesized by solid state reaction under different atmospheres. The transport properties were investigated under the 2-wire mode. Remarkable Electrical Pulse Induced Resistance switching (EPIR) was observed at room temperature for the samples prepared in air. However, the EPIR-effect decreases with increasing temperatures and almost disappears when temperature is more than 450 K. One finds a stronger nonlinearity of the I–V characteristic and an even larger EPIR-effect for the samples sintered in argon. Based on the analysis of the I–V characteristics and the comparison with a standard PN junction, we submit that oxygen vacancies which exist near the surface of LCMO as deep level traps, is one of the key elements for these remarkable EPIR effects.