中文摘要：

采用低氟MOD法在氧化物缓冲层哈氏合金基底上制备了不同结构的YGdBCO多层膜．分析研究了有银修饰与无银修饰YGdBCO多层膜的微结构与性能，对比研究了银修饰在多层膜结构中的作用．XRD与SEM结果表明银修饰改变了YGdBCO生长的热力学参数，使得YGdBCO具有更好的c轴织构度，更为平整致密的表面形貌，并最终提高了YGdB（如的超导性能．为了进一步理解银修饰的作用，用经典成核理论分析了YGdBC0成核过程，按照经典成核理论n轴成核与C轴成核的竞争主要取决于过饱和度，银修饰可能降低了YGdBCO的过饱和度，因而扩大了YGdBCOf轴成核的窗口．

英文摘要：

Various artificial multilayers consisting of YGdBCO superconducting films were fabricated on the oxide buffered Hastelloy substrate by low fluorine metalorganic deposition method. Microscopic and superconducting performances are studied on the composite YGdBCO multilayer films with and without the alternative ultrathin layers of Ag, which comparatively shows the Ag decorating effects in such architectures. X-ray diffraction and scanning electron microscopy implies that the growth thermodynamic parameters of the YGdBCO are modified, resulting in a better c-axis orientation, a higher in-plane texture, as well as a superior surface, and finally give rise to much improvement of superconducting performance. To understand the above Ag decorating effects further, the critical Gibbs free energy △G＊ （r） on the nucleation of MOD-YGdBCO films on the biaxially textured buffer layers is analyzed with respect to the additions of Ag. Acoording to classical nucleation theory, the competition between a-axis and c-axis growths is subject to the supersaturation. As the consequence, Ag additions may reduce supersaturation at the growth interfaces, and hence gives rise to a wider window of c-axis nucleation.