X-ray study of structural domains in the near-surface region of SrTiO3 substrates with Y0.6Pr0.4Ba2Cu3O7/La2/3Ca1/3MnO3 superlattices grown on top

We investigated with synchrotron x-ray diffraction and reflectometry the formation of structural domains in the near-surface region of single crystalline SrTiO(3) (001) substrates with Y(0.6)Pr(0.4)Ba(2)Cu(3)O(7)/La(2/3)Ca(1/3)MnO(3) superlattices grown on top. We find that the antiferrodistortive cubic to tetragonal transition, which occurs at T(STO)=104 K in the bulk and at a considerably higher temperature of at least 120 K in the surface region of SrTiO(3), has only a weak influence on the domain formation. The strongest changes occur instead in the vicinity of the tetragonal to orthorhombic transition in SrTiO(3) around 65 K where pronounced surface facets develop that reach deep (at least several micrometers) into the SrTiO(3) substrate. These micrometer-sized facets are anisotropic and tilted with respect to one another by up to 0.5 degrees 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 SrTiO(3) surface and the multilayer grown on top.