Phase transitions in mixed crystals of ferroelectric betaine arsenate and antiferroelectric betaine phosphate

Abstract

Phase transitions in the mixed crystals system of ferroelectric betaine arsenate (BA) and antiferroelectric betaine phosphate (BP) are investigated by X-ray, dielectric and thermal measurements. The phase diagram of the system BP_(1–x)BA _x in the whole concentration region is given; an antiferroelectric phase transition occurs in the region 0 ≤ x ≤ 0.4, the structural-glass like behavior is observed in the region 0.5 ≤ x ≤ 0.85, and a ferroelectric phase transition takes place in the region 0.9 ≤ x ≤ 1.0.