Synchrotron X-ray diffraction study of SrRuO3/SrTiO3/SrRuO3 nano-sized heterostructures grown by laser MBE

Structural investigation using X-ray synchrotron radiation has been performed on SrRuO₃/SrTiO₃/SrRuO₃ epitaxial heterostructures, with each constituent layer a few unit cell thick grown on (001) SrTiO₃ substrate. Detailed information on the evolution of the in-plane lattice structure has been obtained, in these heterostructures, by grazing incidence diffraction measurements. The samples have been grown by low-pressure pulsed laser deposition. Under our deposition conditions, SrRuO₃ layers grow with an elongated cell perpendicular to the substrate surface. The in-plane pseudocubic lattice parameters do not match the in-plane square SrTiO₃ structure even in the case of very thin SrRuO₃ layers. Such a distortion was found to decrease with increasing the thickness of the SrTiO₃ barrier layer.