EPITAXIAL-GROWTH OF YBA2CU3O7-X THIN-FILMS ON (111)SRTIO3 SUBSTRATES

The growth of YBa2Cu3O7-x thin films deposited by sputtering onto (111 ) SrTiO3 substrates at different temperatures, T-s, was studied by X-r ay diffraction and HRTEM measurements. At all T-s values, the films gr ow epitaxially (113) oriented. Ar low T-s, the growth is pseudomorphic and homogeneously strained. At high T-s, strain is released probably by defect incorporation leading to broad mosaic distributions. In the intermediate T-s range, internal strain is accumulated in the films. T hree domain orientations tilted by 120 degrees were observed in the fi lm plane. Superconductivity with maximum T-c values of 84 K was only o bserved in films prepared at high T-s revealing the orthorhombic struc ture. The oxygenation of the films is probably strain-controlled. (C) 1998 Elsevier Science S.A.