铊系超导单晶的低温生长  

Tl-BASED SUPERCONDUCTING OXIDE SINGLE CRYSTAL GROWTH UNDER LOW TEMPERATURES

作　　者：王益宽[1] 孟宪仁 林明柱[1] 涂清云[1] 张拴勤[1] 柔丽华 林振金 刘振兴[1] 

机构地区：[1]北京师范大学物理系,中国科学院物理所

出　　处：《低温物理学报》1996年第1期58-64,共7页Low Temperature Physical Letters

摘　　要：采用蠕爬型助熔剂ＣａＯ－ＣｕＯ和蒸发型复合助熔剂ＣａＯ－ＣｕＯ－ＮａＣｌ来制备Ｔｌ－Ｂａ－Ｃａ－ＣＵ－Ｏ超导单晶，生长炉最高温度分别为８９０℃和８５０℃，因而实现了铊系单晶的低温生长．生长出的单晶分别是典型尺寸为２．０×１．５×０．２ｍｍ３，Ｔｃ在１００Ｋ与１１９Ｋ之间的Ｔｌ－２２１２相单晶和尺寸为１．２×１．０×０．１ｍｍ３，Ｔｃ约为１１５Ｋ的Ｔｌ－２２２３相超导单晶．采用蠕爬型助熔剂可以降低熔点而不引进其它非组元杂质，但导致熔料蠕爬，对生长大块单晶不利．采用蒸发型复合助熔剂克服了熔料的蠕爬现象，减少了铊的损失，对生长多铜氧层的单晶有利．Abstract Tl-based superconducting single crystals such as Tl-2212 phase crystals which have typical size of 2. 5× 1. 5 × 0. 2mm3 and whose Tos are between 100K and 119K and Tl-2223 phase crystals which have size of 1. 2 × 1. 0 × 0. 1mm3 and whose Tos are about 115K were grown in the closed furnace whose temperature was controlled exactly by a computer using two growth techniques: one uses CaO-CuO as creeping flux which led to the top furnace temperature as low as 890 ℃, the other NaCl as vaporizing flux which led to the top furnace temperature as low as 850℃. So the Tl-based superconducting single crystal growth under low temperactures has been carried out. The creeping flux can make the. melting points lower without introducing non-component impurity, but it causes melt creeping which is unbenificial to the growth of single crystals. And the'vaporizing flux prevents the melt creeping phenomena and lessens the loss of thallium,so it is benificial to the growth of multi-CuO2 sheets single crystals.

关 键 词：铊系 超导体 单晶 单温生长 

分 类 号：TM263[一般工业技术—材料科学与工程]