Thermal barrier materials are used in modern turbines to enable them to run above the melting temperature of the turbine blades. However, to go to higher temperatures (and higher efficiencies) we need new barrier materials with lower thermal conductivities. La2Zr2O7 is one such material however the origin of its low thermal conductivity is unknown. We propose to use the MERLIN spectrometer to determine the origin of the low thermal conductivity and identify the individual vibrations responsible for heat transfer. This will enable us to devise new ways to reduce the thermal conductivity both in La2Zr2O7 and other barrier materials.