Evolution of domain structure and ferroelectric polarization in praseodymium doped BiFeO3 ceramics

Nanoscale domain structure, electric-field-induced polarization switching and electromagnetic strain in lead-free perovskite bismuth ferrite are substantial parameters for nonvolatile magnetoelectric applications. This work highlights nano-to-micro domain morphology, polarization switching and electromechanical mechanisms in (Bi_1-xPr_x)FeO₃ ceramics in the vicinity of the morphotropic phase boundary (MPB). A coexistence of ferroelectric rhombohedral R3c and antiferroelectric orthorhombic Pbam symmetries was identified in conjunction with antiphase domain boundaries and polar nano-regions in the interiors of grains as the system crosses the MPB. Out-of-plane piezoresponse force microscopy indicates decreased ferroelectric polarization and capability of polarization switching as the system approaches the MPB. Frequency- and temperature-dependent dielectric permittivity indicates a relaxor characteristic in all compositions. The O 2p-Fe 3d and O 2p-Bi 6s(p) orbital hybridizations play key roles for evolution of structural distortion, polarization and electromechanical.