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Grazing incidence x-ray diffraction and reflectivity measurements were carried out on ultrathin (a few unit cells thick) superconducting heterostructures, based on Ba[sub 0.9]Nd[sub 0.1]CuO[sub 2+x] and CaCuO[sub 2] individual blocks, using undulator radiation from a third-generation synchrotron. We investigated films with different thicknesses of the intermediate CaCuO[sub 2] block, grown on (001)SrTiO[sub 3] substrates by the pulsed-laser deposition technique with no in situ diagnostic. In this communication we demonstrate that the thickness of such heterostructures can be controlled at the single unit cell level. This analysis shows that the interfaces between the different constituent blocks are very sharp with roughness less than one unit cell. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]