基于喷液雾化-多元共析化学气相沉积法的第二代新型高温超导带材的制备及其性能、取向变化机理研究

本项目拟采用喷液雾化-多元共析化学气相沉积法在新型柔性带材基板CeO2/MgO/Y2O3/Al2O3/Hastelloy C276上制备YBa2Cu3O7-x(YBCO)高温超导薄膜。主要研究YBCO薄膜沉积温度、厚度对其电学性能的影响，并将着重研究超导薄膜的取向由c-轴转变为a-轴的变化机理。通过本项目的研究，不仅可以确定喷液雾化-多元共析化学气相沉积法制备YBCO高温超导带材的工艺参数，解决传统使用固体原料的化学气相沉积法无法长时间提供精确、持续、稳定混合原料蒸气源的难题，还能确定YBCO薄膜在形核初期，临界核取向变化的原因、过程和机理，从而为寻找制备纯c-轴取向的YBCO薄膜的方法奠定理论基础。在研究薄膜取向变化机理时，将以薄膜非自发形核理论为基础，建立晶格简单堆积模型，根据表面能、界面能以及应变能三者之间能量平衡，对YBCO临界核取向由c-轴转变为a-轴的过程和机理进行计算。

This project describes preparation of YBa2Cu3O7-x (YBCO) films on CeO2/MgO/Y2O3/Al2O3/Hastelloy C276 tape by a multielement covolatilizing chemical vapor deposition with a spray-atomizating system. The main contents will be focused on the effects of deposition temperature and the thickness on the electrical performances of the YBCO films and the mechanism in the orientation change of the YBCO films. By the present project, the preparation parameters for the multielement covolatilizing chemical vapor deposition with a spray-atomizating system will be determined, which can slove the issue of disability of suppling precise, stable precursor gases for long deposition time in practical applications for the conventional chemical vapor deposition using solid precursor.Besides, form the study on the mechanism in the orientation change of the YBCO films, the nucluation process and the mechanism of the tranisition from c-axis to a-axis on the YBCO nuclei will be demonstrated. An energy banlance model among the surface energy, interface energy and strain energy will be built based on the stacking theory of the simple crystal lattice.