大块高温超导氧化物单晶生长研究中关键问题探讨

Growth of Large Bulk High T_c Superconducting Oxide Single Crystal:Mechanisms and Technologies

摘要:

高温超导大块单晶体,可以用于精确地测定其晶体结构,掌握结构与各种物性的关系,获得反映其内禀性质的各种信息,对理解和解释高温超导电性机制有重要的理论意义,而且优质的单晶样品也有重要的应用意义.由于高温超导氧化物晶体生长过程中均存在包晶反应及包晶转变,且从液相凝固为固相的过程为非同等成分转变,使这种大块单晶十分不易获得,特别是YBCO,由于其液固相线较陡,制备更为困难.本文讨论了与高Tc氧化物超导单晶生长有关的晶体生长物理理论,以及制备超导氧化物单晶过程中的关键工艺问题,特别是影响其生长速率的因素以及提高生长速率的方法.同时,综述了目前国内外采用的制备方法.

Abstract:

Large bulk HTS single crystal can be used to measure accurately the structure and understand the relation between crystal structure and properties, as well as to obtain more information on its nature for high Tc superconductor. It is important to understand and explain the mechanism of high Tc superconductivity and their applications. It is quite difficult to obtain a large bulk HTS single crystal due to peritectic reaction, peritectic transformation and incoordinate composition transformation in the crystal growth process of HTS oxides, especially, a liquid-solid line of steep slope in YBCO phase diagram. Crystal growth theory related to HTS single crystal grown and techniques, some effects and improvements for crystal growth were discussed in this paper. In addition, some techniques for preparing HTS single crystal were summarized.