Thermal conductivity of platinum and periclase under extreme conditions of pressure and temperature

We have measured the thermal diffusivity and conductivity of platinum and MgO periclase at high pressures (P) and high temperatures (T) by combining the pulsed light heating thermoreflectance technique with a laser-heated diamond anvil cell. The obtained thermal conductivity of platinum shows positive pressure and temperature dependences, reaching about 210 W/m/K at the highest P-T condition of 125 GPa and 1850 K. The thermal conductivity of periclase was determined up to 140 GPa and 1950 K, corresponding to the Earth's lowermost mantle, where the conductivity was about 90 W/m/K. Our measurements allow us to test models for the combined P-T dependence of the thermal conductivity of both metals and insulating materials up to Mbar pressures and thousands of kelvins.