Temperature-dependent field-induced phase transition behavior in Pb(Yb_1/2Nb_1/2)O₃-based antiferroelectrics

Complex lead-based perovskites with the general formula Pb(B_x'B_1-x")O₃, represent an important class of antiferroelectrics beyond the prototypical PbZrO₃ and NaNbO₃. Depending on the combination of B-site species and the degree of cationic ordering, these materials exhibit a wide range of ferroic behaviors, spanning from antiferroelectric to (relaxor) ferroelectric responses. In this study, we investigate (Pb_1-xBa_x)(Yb_1/2Nb_1/2)O₃ polycrystals synthesized via a two-step processing route. Despite displaying antiferroelectric, ferroelectric, or nearly linear dielectric behavior at room temperature, all compositions exhibit double polarization hysteresis loops in proximity to a lower-temperature dielectric anomaly. This dielectric anomaly originates from the competition between antipolar and nanoscale polar regions, and shifts towards lower temperature with increasing Ba content, reflecting the suppression of long-range antiferroelectric ordering. Notably, a composition-invariant temperature scale, T*, is identified and associated with the onset of static correlations among nanoscale polar entities, consistent with behavior reported in other complex Pb-based relaxor ferroelectrics. Superlattice reflections arising from antiparallel Pb²⁺ displacements persist above T*, suggesting an intricate cation-ordering landscape requiring further investigation. These findings underscore the coexistence and competition of polar and antipolar instabilities in complex lead-based perovskites, and their pronounced sensitivity to chemical substitution, thermal fluctuations, and external electric fields.