In-plane thermal conductivity of large single crystals of Sm-substituted (Y₁₋ₓSmₓ)Ba₂Cu₃O₇₋δ

الأصل · EN

We have investigated the in-plane thermal conductivity κab(T,H) of large single crystals of optimally oxygen-doped (Y₁₋ₓ,Smₓ)Ba₂Cu₃O₇₋δ (x=0, 0.1, 0.2 and 1.0) and YBa₂(Cu₁₋yZny)₃O₇₋δ(y=0.0071) as functions of temperature and magnetic field (along the c axis). For comparison, the temperature dependence of κab for as-grown crystals with the corresponding compositions are presented. The nonlinear field dependence of κab for all crystals was observed at relatively low fields near a half of Tc. We make fits of the κ(H) data to an electron contribution model, providing both the mean free path of quasiparticles ℓ₀ and the electronic thermal conductivity κₑ, in the absence of field. The local lattice distortion due to the Sm substitution for Y suppresses both the phonon and electron contributions. On the other hand, the light Zn doping into the CuO ₂ planes affects solely the electron component below Tc, resulting in a substantial decrease in ℓ₀.