Texture and Anisotropy of Jc of ex situ MgB2/Fe Mono—Filamentary Tapes

采用不同粒度的初始MgB2粉末，通过粉末套管法技术制备出非原位单芯MgB2／Fe超导带；测量了不同磁场和温度下MgB2／Fe带的以值．结果表明；Jc具有各向异性，其各向异性的大小受初始粉末尺寸的影响．对剥离铁包套后MgB2芯的XRD图拟合分析表明，MgB2均显示轻微的织构，MgB2／Fe界面处的织构稍强．MgB2的再结晶晶粒尺寸随初始粉末尺寸的增大而增大．讨论了粉末粒度和织构度与Jc各向异性的关联性．

TEXTURE AND ANISOTROPY OF Jc OF EX SITU MgB2/Fe MONO-FILAMENTGRY TAPES

The ex situ MgB2/Fe mono-filamentary tapes have been prepared by powder in tube (PIT) technique starting from MgB2 powders with different sizes. The critical current densities, Jc, of the tapes have been measured at various magnetic fields and different temperatures. It was found that the anisotropy of Jc is influenced significantly by the starting MgB2 powder grain size. The recrystallized grain size of the annealed MgB2 core is increased with increasing of starting powder size. XRD analysis of the MgB2 filaments removing the Fe sheath showed that it existed slight stronger texture at the interface between MgB2/Fe sheath than that in the centre of the MgB2 filaments. The correlation among the starting powder size, texture and anisotropy of Jc was discussed.