Substrate influence on the growth of Co-doped La0.5Sr0.5TiO3−δ epitaxial thin films

We report on the growth of thin films of the diluted magnetic oxide Co-doped La0.5Sr0.5TiO3−δ on SrTiO3 and LaAlO3 substrates. The films are ferromagnetic at room temperature, with no indications of parasite phases from high-resolution x-ray diffraction experiments. The structural mismatch with the substrate is shown to have a strong impact on the growth mechanisms and, consequently, on the surface morphology. In this sense, to grow the films on SrTiO3, for which the mismatch is minimized, appears to be more appropriate for the future integration of Co-doped La0.5Sr0.5TiO3−δ layers into heterostructures for perpendicular transport.