Structural variability in La 0.5Sr 0.5TiO 3±δ thin films

Abstract

La 0.5Sr 0.5TiO 3±δ films were grown by pulsed laser deposition and characterized using aberration-corrected scanning transmission electron microscopy. Single-phase films with low resistivity and a near Ti 3 valence state were stabilized by a large concentration of oxygen vacancies under reducing conductions. In contrast, single-phase films transformed into superlattices upon exposure to an oxygen rich environment through the formation of stacking faults and cation vacancies in order to reach the stable Ti 4 valence state. The resistivity of the superlattices exceeded that of single phase films by two orders of magnitude, indicating that the observed structural order had a significant effect on the overall film properties. © 2011 American Institute of Physics.