液相源金属有机物化学气相法制备YBCO高温超导薄膜

发布时间：2018-01-26 07:19

本文关键词： YBCO薄膜金属有机物化学气相沉积涂层导体结构与性能　出处：《电子科技大学》2010年硕士论文　论文类型：学位论文

【摘要】： YBa2Cu3O7-δ高温超导材料在超导发电机、电动机、强场磁体、限流器、储能系统等方面有着广泛的应用前景。但是直接在柔性的金属Ni基带上制备YBCO涂层导体难度很大,主要是薄膜的快速制备、晶格失配以及离子扩散等问题都有待研究并解决。本论文基于金属有机物化学气相沉积法(MOCVD)在LaAlO3单晶以及双轴织构的镍钨合金(Ni-5%W/Y2O3/YSZ/CeO2)基带上生长YBCO超导薄膜。自行设计和搭建了MOCVD实验系统。通过实验,对在单晶基底上制备YBCO薄膜的生长工艺、结构做了系统的研究,并在此基础之上对在金属基底上制备YBCO涂层导体做了初步的探索性研究,为后期超导带材的快速制备打下了基础。主要内容如下: 1.设计并搭建了实验用的MOCVD系统,并通过实验对系统进行了改进。 (1)设计了一套适合液相金属有机源进液并进行闪蒸的系统,通过使用开有微孔的毛细管,将气体与金属有机源液体混合,保证了连续稳定的金属有机源输运,实现了实验的稳定性,为后期工业化生产研究打下基础。 (2)对不同反应室喷口设计的系统进行对比实验。通过改进系统气流控制系统,使得基底上方的气流速度减慢并容易得到控制。在LAO的单晶基底上制备出了完全c轴取向的YBCO外延薄膜。其薄膜表面均匀,致密,晶粒之间连续性好,测得临界电流密度Jc为0.2MA/cm2。 2.在LaAlO3单晶基底上生长YBCO外延薄膜,研究了工艺参数(温度、总压强、氧分压)对YBCO薄膜的结构、表面形貌以及成分比例的影响,并优化了生长工艺。获得了完全c轴取向YBCO薄膜,面外半高宽为0.4°,薄膜表面晶粒连续、均匀,其临界电流密度达到了0.6 MA/cm2。 3.在多层过渡层结构的Ni-5%W/Y2O3/YSZ/CeO2基底上研究制备YBCO涂层导体。研究了过渡层中CeO2层的面外取向对YBCO薄膜结构的影响,发现面外半高宽越小,获得的YBCO涂层导体结构越?好。在CeO2层半高宽为5.5°时获得(005)峰半高宽仅为3.5°的YBCO外延膜。研究了温度对YBCO涂层导体结构的影响,在865℃获得了完全c轴取向,且面外半高宽为3.0°的高质量薄膜。
[Abstract]:Delta motor YBa2Cu3O7- high temperature superconducting materials in the superconducting generator, high field magnets, limiter, energy storage system has a wide application prospect and so on. But directly on the metal flexible Ni baseband prepared on YBCO coated conductor is very difficult, mainly the rapid thin films preparation, crystal lattice mismatch and ion diffusion are to be studied and solved.
In this paper, metal organic chemical vapor deposition (MOCVD) method based on LaAlO3 single crystal and biaxial texture of the nickel tungsten alloy (Ni-5%W/Y2O3/YSZ/CeO2) YBCO superconducting thin film growth on the baseband is designed and built. The MOCVD experimental system. Through the experiment, the growth process of YBCO thin films on single crystal substrate, the structure of the system on the basis of the research and preparation of YBCO coated conductor on a metal substrate to do preliminary study, fast business late tapes prepared to lay the foundation. The main contents are as follows:
1. the experimental MOCVD system was designed and built, and the system was improved by the experiment.
(1) design a system for liquid metal organic liquid and flash, by using a capillary pore, the gas and the metal organic liquid mixture, to ensure continuous and stable metal organic source transport, to achieve the stability of the experiment, to lay the foundation for the study of the late industrialization production.
(2) the experiments of different reaction chamber nozzle design system. By improving the system of air flow control system, makes the above basal airflow velocity slowed down and easy to be controlled. We prepared the YBCO epitaxial film completely c axis orientation in single crystal substrate LAO. The film surface is uniform, dense, continuous grain well, the measured critical current density of Jc 0.2MA/cm2.
2. in the LaAlO3 single crystal substrate of YBCO epitaxial growth thin film, the effects of process parameters (temperature, total pressure, oxygen partial pressure) on YBCO thin film structure, surface topography and composition proportion, and optimization of the growth process. Was a complete c axis oriented YBCO films, out of plane FWHM is 0.4 degrees, the surface grain film, uniform, the critical current density reached 0.6 MA/cm2.
3. in the preparation of YBCO coated conductor multilayer transition of Ni-5%W/Y2O3/YSZ/CeO2 base layer structure. Effects of plane orientation CeO2 transition layer in the structure of YBCO thin films, found out of plane half width smaller, YBCO coated conductor structure more? Good. At CeO2 layer half width is 5.5 degrees when (005) FWHM is only YBCO epitaxial film of 3.5 degrees. Effect of temperature on YBCO coated conductor structure has been studied and obtained a complete c axis oriented at 865 DEG C, and out of plane FWHM for high quality thin films of 3 degrees.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TM26

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