All chemical YBa(2)Cu(3)O(7) superconducting multilayers: Critical role of CeO(2) cap layer flatness

作者：Coll M^*; Gazquez J; Huehne R; Holzapfel B; Morilla Y; Garcia Lopez J; Pomar A; Sandiumenge F; Puig T; Obradors X

来源：Journal of Materials Research, 2009, 24(4): 1446-1455.

DOI：10.1557/JMR.2009.0160

New advances toward microstructural improvement of epitaxial CeO(2) films grown by chemical solution deposition and their use as buffer layers for YBa(2)Cu(3)O(7) (YBCO) films are presented. We demonstrate that the degree of epitaxy and the fraction of (001) atomically flat surface area are controlled by the incorporation of tetravalent (Zr(4 )) or trivalent (Gd(3 )) cations into the ceria lattice. The degree of epitaxy has been investigated by means of Rutherford backscattering spectroscopy-channeling and reflection high-energy electron diffraction. In addition, we use a new methodology to quantify the fraction of (001) atomically flat area from atomic force microscopy images. Results are further correlated with the superconducting properties, microstructure, and texture of YBCO films grown by the trifluoroacetate route. A comparison with pulsed laser deposition and YBCO films grown on the same ceria layers is also presented. This growth procedure has allowed us to obtain all chemical multilayer films with controlled microstructure and critical current densities above 4 MA cm(-2) at 77 K.

• 出版日期2009-4