X-ray study of structural domains in the near-surface region of SrTiO 3 substrates with Y0.6Pr0.4Ba 2Cu3O7/La2/3Ca1/3MnO 3 superlattices grown on top

Abstract

We investigated with synchrotron x-ray diffraction and reflectometry the formation of structural domains in the near-surface region of single crystalline SrTiO3 (001) substrates with Y0.6 Pr0.4 Ba2 Cu3 O7 / La2/3 Ca1/3 MnO3 superlattices grown on top. We find that the antiferrodistortive cubic to tetragonal transition, which occurs at TSTO =104 K in the bulk and at a considerably higher temperature of at least 120 K in the surface region of SrTiO3, has only a weak influence on the domain formation. The strongest changes occur instead in the vicinity of the tetragonal to orthorhombic transition in SrTiO3 around 65 K where pronounced surface facets develop that reach deep (at least several micrometers) into the SrTiO3 substrate. These micrometer-sized facets are anisotropic and tilted with respect to one another by up to 0.5° along the shorter direction. Finally, we find that a third structural transition below 30 K gives rise to significant changes in the spread of the c -axis parameters. Overall, our data provide evidence for a strong mutual interaction between the structural properties of the SrTiO3 surface and the multilayer grown on top. © 2008 The American Physical Society.