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

TL;DR

This study investigates how zinc doping affects the in-plane thermal conductivity of YBCO single crystals across a broad temperature range, revealing significant reductions and suppression of magnetic field effects with increased doping.

Contribution

It provides new experimental data on Zn-doped YBCO's thermal conductivity and analyzes the impact of doping on quasiparticle excitations and magnetic field response.

Findings

Thermal conductivity decreases with Zn doping, eliminating the peak at high doping levels.

Magnetic field effects on thermal conductivity are suppressed by Zn doping.

Remnant magneto-thermal resistivity is reduced to about one-tenth in doped samples.

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.