Thermal diffusivity of isotopically enriched<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>12</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>diamond

Type-IIA diamond single crystals containing approximately 0.1%, 0.5%, and 1% C were synthesized and their thermal diffusivities were measured at room temperature by the thermal-wave-mirage technique, resulting in the highest room-temperature thermal Diffusivity of any solid naturally occurring or previously synthesized.

Abstract

Type-IIA diamond single crystals containing approximately 0.1%, 0.5%, and 1% $^{13}\mathrm{C}$ were synthesized and their thermal diffusivities were measured at room temperature by the thermal-wave-mirage technique. The measured value (18.5 ${\mathrm{cm}}^{2}$/s) of the 0.1% $^{13}\mathrm{C}$ crystal was 50% higher than the 1% $^{13}\mathrm{C}$ (natural isotope abundance). This is the highest room-temperature thermal diffusivity of any solid naturally occurring or previously synthesized. The laser damage threshold at 193 nm for the isotopically enriched crystal is more than an order of magnitude higher than that of natural diamond.