Mocvd Preparation Of Ybco Superconducting Layer Strip Process Research

The Second-generation HTS tapes of YBa2Cu3O7_δ （YBCO） gained the worldwide attention because of its high critical temperature, low preparation cost, good electrical properties. At the same time, it has a wide range of applications in strong electric fields, such as superconducting motors, superconducting generators, superconducting energy storage, and superconducting power transmission cable. Currently in many film preparation processes of superconducting films, MOCVD method is the very valuable for high deposition rate and large scale deposition of YBCO films.In this dissertation, YBCO films were deposited on CeO2/YSZ/Y2O3buffered rolling assisted biaxial textured Ni-W₅at%metal substrate with self-made MOCVD system. And this work is a preparation for the later large scale YBCO deposition. The main contents are as follows:1. We improved the self-made MOCVD system. The equipment was so important in our research so that a lot of work had been done to improve the self made MOCVD system for better application. In order to reduce the risk of blocking, the vent of the injector was changed which made the metal organic sources evaporated as a form of mist. At the same time, the heating method in the reacting chamber changed from single resistance wire heating to halogen providing photo-assisted heating.2. In the experiment, Ba metal organic source was not as stable as Y and Cu metal organic sources which made it quite difficult to keep the study repeatability. So high volatility, low melting point, and good stability Ba mental organic sources were studied by add assistant ligand in the original Ba（TMHD）2, which ensure the smooth progress of the study. And also the effects of different Ba sources to the final films were studied in detail.3. We learn the difference in film processes between the resistance heating method and the photo-assisted heating method. Using of photo-assisted heating, the complete c-axis YBCO superconducting films was grown under the optimum process, which had excellent in-plane texture with full width at half maximum （FWHM） value of （103）=4.8°and out-of-plane texture with FWHM of （005）=1.8°and its critical current density Jc was0.2MA/cm2. Although the critical current density was close in a long deposition area, the composition and morphology was different, it’s need for further improvement.