Growth temperature control of the epitaxy, magnetism, and transport in SrTiO3(001)/La0.5Sr0.5CoO3 thin films

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 La0.5Sr0.5CoO3 thin films grown on SrTiO3(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 O-2, our results also identify a narrow deposition temperature window similar to 600-625 degrees 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. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3622621]