Effect of oxygen annealing on Pr0.7Ca0.3MnO3 thin film for colossal electroresistance at room temperature

Abstract

We studied an appropriate annealing condition of Pr0.7Ca0.3MnO3 (PCMO) thin film that can show good resistive switching characteristics for resistance random access memory applications and also tried to elucidate the mechanism of the resistive switching of PCMO thin film at room temperature. We could observe that crystal structure of PCMO film was changed by oxygen annealing. From x-ray photoelectron spectroscopy measurements, we can conclude that the excess of oxygen by oxygen annealing of PCMO film leads to an increase of Mn4+ content at the PCMO surface with a subsequent change in the Mn4+/Mn3+ ratio at the PCMO surface. The resistance ratio of high resistance state and low resistance state was increased by oxygen annealing of PCMO thin film. This can be explained as follows. The change of the Mn4+/Mn3+ ratio at the PCMO surface by oxygen annealing leads to the change of characteristics of Au-PCMO interface domain and therefore results in the change of the resistance ratio. (c) 2006 American Institute of Physics.