Quasiparticle contribution to heat carriers relaxation time in DyBa2Cu3O7-x from heat diffusivity measurements - art. no. 184521

It is shown that the controversy on phonons or electrons being the most inf luenced heat carriers below the critical temperature of high-T-c. supercond uctors can be resolved. Electrical and thermal properties of the same DyBa2 Cu3O7-x monodomain have been measured for two highly different oxygenation levels. While the oxygenated sample DyBa2Cu3O7 has very good superconductin g properties (T-c = 90 K), the DyBa2Cu3O6.3 sample exhibits an insulator be havior. A careful comparison between measurements of the thermal diffusivit y of both samples allows us to extract the electronic contribution. This co ntribution to the relaxation time of heat carriers is shown to be large bel ow T-c and more sensitive to the superconducting state than the phonon cont ribution.