Thermal conductivity of single and multi-stacked DI-BSCCO tapes

We have measured the temperature dependence of the thermal conductivity, κ(T)κ(T), for DI-BSCCO®DI-BSCCO® tapes fabricated by Sumitomo Electric Industries, Ltd., which are (Bi,Pb)2Sr2Ca2Cu3O8+x(Bi,Pb)2Sr2Ca2Cu3O8+x tapes sheathed with Ag or Ag–Au alloy. The κ(T)κ(T) of the tape sheathed with Ag (residual resistance ratio (RRR) = 15) decreases with decreasing temperature and starts to increase rapidly below 60 K, with a maximum at around 15 K. On the other hand, the κ(T)κ(T) of the tape sheathed with Ag–5.4 wt%Au alloy has a very low value that decreases monotonically with decreasing temperature. At around 77 K, the absolute values of κ(T)κ(T) for both tapes were about 260Wm-1K-1 and 80Wm-1K-1, respectively. The κ(T)κ(T) of a stacked sample, in which six DI-BSCCO tapes sheathed with Ag are soldered, was also measured. The measured κ(T)κ(T) was fairly well reproduced by the estimated κ(T)κ(T), which was calculated using the measured κ(T)κ(T) of the single tape and solder.