Influence of tilting of SrTiO3 substrates on the morphology and superconductivity of YBa2Cu3O7-delta thin films

Morphology and superconductivity of YBa2Cu3-(7-delta) thin films grown on v icinal SrTiO3 substrates by pulsed laser deposition are studied. Ex situ at omic force microscopy and scanning tunneling microscopy are used to observe the film surface morphology, Novel anisotropic step-mediated island growth is found for the first time. The anisotropic evolution of the surface morp hology is discussed in terms of the anisotropic surface diffusion. Relative ly low deposition temperature (750 degreesC is found to be the optimum cond ition for ultra-smooth step-mediated growth of YBa2Cu3O7-delta thin films. Tilting of the substrates is found favorable for the superconductivity of Y Ba2Cu3O7-delta thin films grown an them, The critical temperature at zero r esistance (T-c0) of YBCO films is found to be a function of the vicinal ang le of the SrTiO3 substrates. (C) 2001 Elsevier Science B.V. All rights rese rved.