中文摘要：

超导薄膜所受的应力对其临界转变温度Tc具有重要的影响，研究应力对超导薄膜Tc的影响对获得更高Tc材料具有重要意义．本文采用溶胶-凝胶法，在LAO单晶基板上制备了Y2O3／YBCO薄膜，并研究了Y2O3缓冲层对不同厚度YBC0超导薄膜的临界转变温度的影响．研究发现，当YBCO薄膜厚度为90nm时，由于Y203和YBCO薄膜的晶格错配，在YBCO／Y2O3薄膜的a-b面内引入了压应力，增加了c轴的晶格常数，结果提高了YBCO薄膜的临界转变温度．当YBCO薄膜的厚度较大时（如230nm），由晶格错配引起的应力通过位错的形式得以释放，YBCO薄膜的Tc变化不大．

英文摘要：

The strain in superconductor films plays an important role in improving superconducting critical transi- tion temperature （To）. In order to obtain higher Tc YBCO superconducting film, it is necessary to investigate the effect of the strain on the microstructures and properties of YBCO film. In the paper, YBCO films were prepared on Y2O3 buffered LAO substrates using sol-gel method, and the effect of thickness of YBCO films on Tc was investiga- ted. The results show that Tc of the film was enhanced when the thickness of YBCO film was 90 nm, which is inter- preted as follow. Due to the lattice mismatch between Y2 03 and YBCO films, the compressive epitaxial strhin was introduced into a-b plane of YBCO films, which increased the lattice constant in c-axis direction of YBCO and thus enhanced To. When the thickness of YBCO film is 230 nm, the strain derived from the lattice mismatch is released as a result of the formation of some defects, so Tc of the film is almost unchanged.