TEM AFM STUDY OF THE GROWTH OF LA2-XSRXCUO4 THIN-FILMS LASER-DEPOSITED ON (100)SRTIO3 SUBSTRATES/

The growth characteristics of La2-xSrxCuO4 thin films of various thick nesses (10-150 nm), epitaxially grown by laser ablation on (100) SrTiO 3 substrates, were analysed by transmission electron microscopy (TEM) and atomic force microscopy (AFM). A periodic surface roughness with a n important peak valley amplitude (about 20% of the film thickness) wa s clearly observed in the films thicker than 25 nm. The period of the undulations did not depend on the deposited thickness. In contrast, AF M experiments performed on thinner films showed a perfect smoothness o f the surface and a complete coverage of the substrate. These results were examined in connection with the fabrication of YBCO/LSCO (YBa2Cu3 O7-delta/La2-xSrxCuO4) high T-c superconducting multilayer films.