Theory of high-temperature phase transitions in actinide oxides

Abstract

A theory of phase transitions in actinide oxides which includes the effects of both Frenkel and Schottky defects has been developed. Coulomb interaction between charged defects and its effects on both defect formation energy and configurational entropy have been shown to be key factors in describing the phase transition. This simple model accounts for most of the experimental information available but predicts lower defect concentrations than have been observed in recent neutron-scattering experiments. An extended treatment which should account for that effect as well is suggested.