Phase Transition Anomalies in Crystals with Defects

Abstract

A brief review of the evolution of theoretical concepts of the anomalous behaviour of physical quantities near the second order phase transitions in systems with defects is provided. For the «local phase transition temperature» defects the «imperfect scaling» theory is shown to be completely inapplicable. In the case of extremely small defect concentrations the scaling regime inherent in a system absolutely free of defects may exist and thereafter, as the phase transition temperature is approached, the system switches to the strong binding regime which has not been studied yet. For a noticeable concentration of defects the system transforms to the strong binding regime within the range of applicability of the mean-field approximation.

The self consistent procedures accounting for defects within the framework of the mean-field theory in the region preceding that of the strong-binding regime are described in detail.