THERMAL-CONDUCTIVITY OF ZN, PR AND TB DOPED YBCO SINGLE-CRYSTALS - THEORY AND EXPERIMENT

The thermal conductivity K(T) vs temperature has been measured for (Y,Pr)Ba2Cu3O7, (Y,Tb)Ba2Cu3O7 and YBa2(Cu,Zn)(3)O-7 single crystals from 10 less than or equal to T less than or equal to 280K. For YBa2Cu3O7 (YBCO), a strong enhancement in K(T) is observed for T less than or equal to T-c with a peak in K(T) at approximately T approximate to T-c/2 with a sharp change in slope of K(T) at T-c. These results are similar to those reported previously. For the selectively doped YBCO, the peak in K(T) is shifted to lower temperatures and occurs at T approximate to 20K independent of T-c and the impurity concentration. In addition, the sharp change in slope of K(T) at T-c is not apparent for the doped crystals. These results are discussed along with a theoretical model for electronic conduction including both impurity and inelastic scattering from spin fluctuations.