抄録
The authors have been studying the preparation of dense and highly oriented bulk sample of Bi based superconductor by the floating zone method. Recently, the effects of Ag doping on Jc and the related properties were investigated in FZ samples. The results obtained are summarized as follows. 1. Ag exists not only in grain boundary but also in 2212 grain. 2. Ag doping in the range of 0-10% does not significantly affect Jc. The doping of Ag over 10% degrades oriented structure resulting in decrease of Jc value. 3. The contact resistance at current terminal is drastically lowered by Ag doping. High contact resistance in undoped sample was suggested to potentially lower Jc measured value. 4. Measurement of complex magnetic susceptibility revealed FZ sample contains weak links. It was suggested that Ag doping improves weak link properties. Peak area in temperature dependence of imaginary part of complex magnetic susceptibility was proposed as an index for weak links in sample. Jc decreases with increase of this index value.
