摘要
Floating zone method with optical radiation heating was applied to growing a class of R2PdSi3(R=Pr,Tb and Gd) single crystals due to its containerless melting and high stability of the floating zone.One serious problem during the single crystal growth,precipitates of secondary phases,was discussed from the following four parts:precipitates from the raw materials and preparation process,precipitates formed during the growing process,precipitates in the melts and precipitates in the grown crystals.Annealing treatment and composition shift can effectively reduce the precipitates which are not formed during the crystallization but precipitated on post-solidification cooling from the as-grown crystal matrix because of the retrograde solubility of Si.
利用具有无坩埚、高稳定性等特性的光辐射悬浮区熔法,制备R2PdSi3(R=Pr,Tb和Gd)单晶。从原材料和试样制备过程、单晶生长过程、熔体内部以及单晶基体4个方面研究单晶制备过程中一个很重要的现象,第二相沉淀。采用退火热处理方法以及给料棒成分微调法可以有效减少凝固后期冷却过程中由于Si溶解度降低析出的条纹状RSi(R=Pr,Tb和Gd)沉淀。
基金
Project (2008629045) supported by the China Scholarship Council (Constructing High-Level University Project)