RE211晶须实验研究的现状及意义

 作为RE123（REBa2Cu3O7-δ）包晶分解的产物，RE211（RE2BaCuO5）在构成RE123块材、薄膜及涂层导体中扮演着一个重要的角色。在RE123块材中，RE211粒子与RE123晶粒的晶界缺陷能够产生强磁通钉扎，有利于提高临界电流密度（Jc）。探明RE211包裹物形成的原因，对于获得高品质RE123膜十分重要；对于涂层导体，在交替生长Y211与Y123多层膜的过程中引入第二相的纳米尺度的Y211粒子，可以大大提高高磁场下的Jc值。由于RE211对RE123的形成及其超导性能有很大的影响，研究RE211的生长并且生长出大线度RE211晶须，就有很重要的意义。本文简要总结了RE211晶须实验研究的成果和现状，对RE211晶须实验和理论研究的意义以及应用前景进行了讨论；报道了笔者所在小组采用熔体法在单晶炉中生长大尺寸（最长15.5mm）Sm211晶须的方法和条件

Progress in Experiment Researches on RE211 Single Crystal Whiskers

In the resultant phase of peritectic decomposition of the RE123 (REBa2Cu3O7-δ), RE211(RE2BaCuO5) plays an important role in the construction of RE123 bulk, thin film, and coated conductor. In RE123 bulks, the boundary defects between RE211 particles and RE123 grains serve as strong flux pinning and thus help to increase the critical current density(Jc). In RE123 thin films, the influencing factors of formation of RE211 inclusions are important for obtaining high quality RE123 thin film. In the fabrication of coated conductor, second-phase Y211 particles of nanometer size were introduced by growth of alternating multilayer of ultra thin Y211 and Y123. Such a structure greatly enhances the Jc under a high magnetic field. As RE211 greatly influences the RE123 fabrication and its superconductive property, the growth of RE211 and the growth of large size Sm211 single crystal whiskers are a very important. In this paper, the experimental studies on RE211 single crystal whisker are reviewed, including also large size Sm211 single crystal whiskers(length over 15.5mm) growth by melt-method in single crystal stove.