The authors report a detailed study of the influence of deposition temperature on the microstructure, phase purity, nanoscale chemical homogeneity, stoichiometry, and magnetic and electronic properties of epitaxial La 0.5Sr0.5CoO3 thin films grown on SrTiO 3(001) substrates via reactive dc magnetron sputtering. The results are interpreted in terms of the temperature-dependent interplay between crystallization, strain relaxation, and cation mobility (which improve with increasing deposition temperature), and oxygenation (which deteriorates at the highest deposition temperatures). In addition to the established approach to epitaxial sputter deposition based on high temperature deposition combined with subsequent ex situ annealing in O2, our results also identify a narrow deposition temperature window ∼600-625 C, where single phase, highly crystalline, low surface roughness epitaxial films can be obtained with close to ideal stoichiometry without postdeposition annealing. Electronic and magnetic properties similar to bulk single crystals can be obtained in this region.
|Original language||English (US)|
|Journal||Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films|
|State||Published - Sep 2011|
Bibliographical noteFunding Information:
Work at UMN supported primarily by NSF (DMR-0804432), with additional support from DOE (DE-FG02-06ER46275, specifically scattering characterization). Research at ORNL (M.V.) supported by the U.S. DOE Office of Science, Division of Materials Science and Engineering. J.G. acknowledges the Spanish MEC 2007-0086 and the European Research Council Starting Investigator Award. The authors are grateful to J. T. Luck for STEM specimen preparation.