Anisotropy of thermal conductivity in single crystals YBa2Cu3O7

The anisotropy of thermal conductivity It in single crystals YBa2Cu3O7 has been studied. The temperature dependence of k in c-direction is well described by the lattice thermal conductivity (T-max = 60 K; k(max) = 4 W/mK; T-D = 140 K). The precise measurements reveal the hysteretic behavior of out-of-plane thermal conductivity. In ab-direction the upturn in ii for temperatures below T-c is observed and temperatures of thermal conductivity peaks in ab-and c-direction coincide. Theoretical analysis suggests a model in which an observed peak below T-c in thermal conductivity for ab-direction is ascribed to a quasiparticle contribution. (C) 2000 Elsevier Science B.V. All rights reserved.