STRAIN ANALYSIS AND STRUCTURAL CHARACTERIZATION OF SRCUO2 CACUO2 INFINITE-LAYER SUPERLATTICES/

A detailed structural characterization of SrCuO2/CaCuO2 infinite layer superlattices is presented. The analyses are performed by using high- resolution X-ray diffraction, reciprocal space mapping and X-ray specu lar reflectivity. In addition, preliminary results of X-ray photoelect ron spectroscopy are reported, The X-ray analyses confirm the high str uctural quality of infinite layer superlattices deposited by pulsed la ser technique on slightly misoriented SrTiO3 substrates. The strain an alyses indicate that (i) a macroscopic tilt of the superlattice with r espect to the substrate lattice occurs, and (ii) the SrCuO2 layers are in a relaxed state, while the CaCuO2 unit cells are tetragonally dist orted with respect the SrCuO2 lattice. The low-angle X-ray measurement s reveal good interfacial properties and indicate a partial correlatio n of the interface roughness across the layers. A computer simulation of the experimental X-ray specular reflectivity patterns yields an ave rage interface roughness of about 4 Angstrom. Finally, the X-ray photo electron spectroscopy investigations confirm the good quality of the i nfinite layer superlattices with a correct stoichiometric contents and , particularly, a chemical state of CuO2 planes similar to that of typ ical high quality superconducting YBCO thin films. (C) 1997 Elsevier S cience B.V.