The Effect of Giant Striction and Thermal Expansion Anomalies in Systems with Structural Instabilities

Abstract

AbstractA simple fluctuation theory analogous to the spin‐fluctuation theory of the magneto‐volume effect is presented to discuss the phenomenon of giant striction, associated with displacive phase transitions, and thermal expansion anomalies. It is argued that the giant striction accompanying the phase transition to the incommensurate charge density wave state is responsible for the low temperature anomalous expansion of α‐uranium and α‐plutonium. The spontaneous striction values in these materials are estimated to be 4.57 × 10−3 and 1.82 × 10−2 comparable with those known for systems with giant magnetostriction.