ROLE OF SB DOPING IN GOVERNING THE THERMAL-CONDUCTIVITY OF BI-PB-SR-CA-CU-O SUPERCONDUCTORS BETWEEN 10-K AND 150-K

In this paper, we report on the role of Sb doping in causing differences in the nature of the thermal conductivity (k) versus temperature (T) plot between 10 and 150 K for Bi1.6Pb0.4Sr2Ca2Cu3Ox superconductors. The peak in the thermal conductivity plot shifts towards lower temperature and also becomes sharper with Sb doping. The increase in the static imperfections as a result of Sb doping is quantitatively estimated following the Tewordt and Wolkhausen [TW] model. The role of static imperfections in governing the nature of the k-T plot is discussed. We conclude that the sharp rise in k below the transition temperature (T(c)) for Sb-doped samples can be better accounted for by invoking the concept of suppression of quasiparticle scattering, rather than by the commonly believed concept of increased phonon mean free path due to condensation of carriers.