Characteristic features of the change of domain structure in mixed [(NH4)1−x Rbx]3H(SO4)2 crystals in the vicinity of superprotonic phase transition

Abstract

X-ray diffraction measurements of mixed [(NH4)1−xRbx]3H(SO4)2 crystals of different compositions are performed. The characteristics of the change of the domain structure in the vicinity of the supeprotonic-ferroelastic phase transition in crystals of different compositions are studied and compared with the variations of the crystal structure in the course of gradual substitution of ammonium by rubidium. This phase transition is theoretically described based on the phenomenological theory of a high-temperature phase transition.