A reorientation of the PO₃-groups and radiation damage effect in ferroelectric phase transition studied by CW-EPR of PO₃²⁻radical in glycine·H₃PO₃single crystal

Abstract

Abstract EPR of γ-ray generated PO3 2- radicals indicates that the four radical centers are equivalent in the paraelectric phase and become inequivalent in the ferroelectric phase due to a ±3° rotation. The phase transition temperature is shifted by irradiation from Tc = 224 K to Tc = 180 K. The molecular mechanism of the order-disorder phase transition is discussed