Thermal conductivity of YBa₂Cu₃O₇ from 7 K to 260 K

Abstract

Thermal conductivity of YBa₂Cu₃O₇ has been measured on samples of a few mm thickness. Above T_c thermal conductivity is found to decrease with increase in temperature, pointing towards a contribution to thermal resistivity from three-phonon Umklapp processes. Below T_c thermal conductivity increases rapidly before reaching a maximum at about 50 K and then falls towards zero at lower temperatures. The experimental set up is described and results discussed.