Thermal conductivity of YBa2Cu3O7 has been measured on samples of a few mm thickness. AboveTc thermal conductivity is found to decrease with increase in temperature, pointing towards a contribution to thermal resistivity from three-phonon Umklapp processes. BelowTc 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.
