Thermal conductivity of YBa2[Cu(1-x)Znx]3O(7-y) single crystals

Abstract

The in-plane thermal conductivity K(T) of Zn-doped YBCO single crystals (YBCO:Zn) has been investigated in the temperature range from 5 to 250 K and in magnetic fields up to 30 kOe. The thermal conductivity decreases substantially with increase of the Zn concentration providing reduction in the thermal conductivity peak and its disappearance at a high content of the dopant. At temperatures below 15 K the K(T) dependencies are functionally similar for all the samples. The magnetic field effect on the thermal conductivity is strongly suppressed by doping even in the crystal with the lowest Zn content. For YBCO:Zn with x=0.003 at temperatures below 25 K the magnitude of remnant magneto-thermal resistivity is about one tenth of that for pure YBCO. Analysing experimental data we use the theory of thermal conductivity in high-Tc superconductors and speculations about the modification of quasiparticle excitation spectrum due to the Cooper pair breaking.