HEAT-TRANSPORT IN THE INSULATING PHASES OF SM1-XCU3OY HIGH-TEMPERATURE SUPERCONDUCTORS(XBA2)

Thermal conductivity (kappa) of two series of high temperature superco nductors with general formula Sm1+x Ba2-xCu3Oy have been measured. Bot h series begin with the same sample of T-c = 90.4 K and extend to nons uperconducting phases. The first series is of 123 cation stoichiometry and variable oxygen content y, the second is a series of solid soluti ons with variable x. The temperature dependences of kappa are very sim ilar for superconducting partner samples from both series (i.e. with t he same T-c), whereas the nonsuperconducting samples reveal dramatic d ifferences. We propose to attribute the huge increase of kappa and the change of its temperature characteristics of insulating oxygen defici ent sample to some additional heat carriers, supposedly of magnetic or igin. Absence of this additional heat transport mechanism for insulati ng solid solution allows to treat it as a proper reference for estimat ion of phonon contribution in the superconducting 123 compounds.