Brillouin scattering and the extent of disorder in fluorite crystals at high temperatures

Many crystals with the fluorite structure show a specific heat anomaly at a temperature T c a few hundred degrees below the melting temperature. It is generally assumed that this anomaly is due to the development of extensive disorder in the anion sublattice. The authors have studied this disorder using both Brillouin scattering and theoretical methods and they discuss the extent of the disorder.