YBCO超导晶体生长规律的实时原位观察研究  

In situ observation of growth process of single domain YBCO superconductors

作　　者：李佳伟[1] 杨万民[1] 陈森林[1] 王妙[1] 冯忠岭[1] 

机构地区：[1]陕西师范大学物理学与信息技术学院,西安710062

出　　处：《中国科学：物理学、力学、天文学》2015年第2期66-73,共8页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(批准号:51342001;51167016);教育部科学技术研究重大项目(编号:311033);高等学校博士学科点专项科研基金(编号:20120202110003);中央高校基本科研业务费专项资金(编号:GK201305014;GK201004009)资助项目

摘　　要：本文采用顶部籽晶熔渗法(TSIG)成功制备出了不同过冷度下、不同保温时间的系列YBCO单畴超导块材;同时采用原位观察的方法,借助高温摄像技术实时记录了YBCO晶体的生长过程.通过对在不同过冷度、不同保温时间YBCO晶体生长形貌的分析和研究,结果表明:YBCO晶体起始外延生长温度为1008°C,单畴生长温度窗口为988°C–1008°C;在确定的过冷度下保温时,YBCO晶体的起始生长速率很快,最大平均生长速率达到0.95 mm h-1,之后,先快速衰减,然后逐渐趋于稳定;在YBCO晶体生长温区范围内,过冷度越大,生长速率越快,晶体生长的平均速率与过冷度之间的关系可以用Ra=a(△T)b公式来描述;YBCO晶体的瞬时生长速率在0.01–0.72 mm h-1之间,具有很大的波动性,但瞬时生长速率的平均值随过冷度的增大呈线性增加.这些结果对于进一步制备高质量的YBCO块材具有重要的指导意义.In situ observation of isothermal growth process of single domain YBCO bulk superconductors under different supercooling by top-seeded infiltration growth technique has been carried out via high temperature video camera. The research and analysis of macrographs of YBCO bulks under different growth time and supercooling are reported. It is found that the initial epitaxial growth temperature is about 1008~C and the growth temperature window is ranged from 988~C to 1008~C.The average growth rate of YBCO bulk increases with increasing supercooling and decreases with growth time when supercooling temperature is fixed, which is well consistent with the formula Ra=a（AT）b; In addition, It is also discovered that the instantaneous growth rate is a random scattering data with time ranging from 0.01-0.72 mm h-i, but the mean value of instantaneous growth rate linear increase with supercooling. These results are of great significance for fabricating high quality YBCO bulk.

关 键 词：晶体生长速率 YBCO 高温超导 顶部籽晶熔渗法 

分 类 号：O78[理学—晶体学]