Annealing-Dependent Morphotropic Phase Boundary in the BiMg0.5Ti0.5O3–BiZn0.5Ti0.5O3 Perovskite System

• Published in: Materials Vol. 15; no. 19; p. 6998
• Main Authors: Cardoso, João Pedro V., Shvartsman, Vladimir V., Pushkarev, Anatoli V., Radyush, Yuriy V., Olekhnovich, Nikolai M., Khalyavin, Dmitry D., Čižmár, Erik, Feher, Alexander, Salak, Andrei N.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-10-2022; MDPI
• Subjects: Annealing; conversion polymorphism; Cooling; Ferroelectric materials; Ferroelectricity; Ferroelectrics; high-pressure synthesis; Lead zirconate titanates; lead-free; Microscopy; Morphology; Orthorhombic phase; Perovskites; Phase boundaries; Phase diagrams; Piezoelectric ceramics; piezoresponse force microscopy; Polymorphism; Solid solutions; Temperature; X-ray diffraction
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15196998

The annealing behavior of (1-x)BiMg0.5Ti0.5O3–xBiZn0.5Ti0.5O3 [(1-x)BMT–xBZT] perovskite solid solutions synthesized under high pressure was studied in situ via X-ray diffraction and piezoresponse force microscopy. The as prepared ceramics show a morphotropic phase boundary (MPB) between the non-polar orthorhombic and ferroelectric tetragonal states at 75 mol. % BZT. It is shown that annealing above 573 K results in irreversible changes in the phase diagram. Namely, for compositions with 0.2 < x < 0.6, the initial orthorhombic phase transforms into a ferroelectric rhombohedral phase. The new MPB between the rhombohedral and tetragonal phases lies at a lower BZT content of 60 mol. %. The phase diagram of the BMT–BZT annealed ceramics is formally analogous to that of the commercial piezoelectric material lead zirconate titanate. This makes the BMT–BZT system promising for the development of environmentally friendly piezoelectric ceramics.