Structure and Relaxor Behavior of (0.5-x)BiFeO₃-0.5PbFe_0.5Nb_0.5O3-xPbTiO₃ Ternary Ceramics

Ceramics of the quasi-binary concentration section (0.1 = x = 0.2, ?x = 0.025) of the ternary solid solution system (0.5 - x)BiFeO3-0.5PbFe(0.5)Nb(0.5)O(3)-xPbTiO(3) were prepared by the conventional solid-phase reaction method. An X-ray study at different temperatures revealed that (0.5 - x)BF-0.5PFN-xPT ceramics have a cluster morphology. Clusters have different modulation, crystal lattice symmetry, and chemical composition. The presence of a cluster structure in a solid solution with heterovalent substitution, consisting of regions rich in Ti+4, Nb+5, or Fe3+, has led to the appearance of Maxwell-Wagner polarization in the studied ceramics. The study of the dielectric characteristics revealed the relaxor-like behavior of the studied ceramics. The grain morphology, dielectric, pyroelectric, and piezoelectric properties of the selected solid solutions were investigated. The highest piezoelectric coefficient, d(33) = 280 pC/N, was obtained in the 0.3BiFeO(3)-0.5PbFe(0.5)Nb(0.5)O(3)-0.2PbTiO(3) ceramics. Study of the dielectric characteristics of all samples revealed relaxor ferroelectric behavior and a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 140-170 degrees C.