This study investigates the origin of polarization in bismuth sodium titanate-based ceramics, specifically 0.2(Ba0.4Sr0.6TiO3)-0.8(Bi0.5Na0.5TiO3) (BST246). The research reveals that Ti⁴+ contributes less than a third to the overall polarization, while displacements of O²⁻ ions and A-site cations, particularly Bi³⁺, are significant. The analysis of the ferroelectric transition in this system provides insights into understanding such transitions in other ferroelectric perovskites, especially those containing lone pair elements. BST246 exhibits a coexistence of tetragonal and cubic phases at room temperature, allowing for a direct comparison between polar and nonpolar structures. The study shows that the polarization is influenced by the displacement of atoms, with Bi³⁺ ions showing a significant off-center displacement. The research also highlights the role of polar nanoregions (PNRs) in the relaxor ferroelectric behavior of BST246. The study uses high-resolution neutron diffraction, ab initio calculations, and electrical measurements to analyze the structural and electrical properties of BST246. The results show that the tetragonal and cubic phases have similar free energies, and the material exhibits nonergodic relaxor ferroelectric behavior at lower temperatures and ergodic behavior at higher temperatures. The depolarization temperature (Td) of BST246 is around 110 °C, corresponding to a transition from nonergodic to ergodic states. The study also reveals that the displacement of Bi³⁺ ions is significant, contributing a major part to the total A-site contribution to the dipole moment. The overall dipole moment is calculated using the Berry phase approach, showing that Bi³⁺, Ti⁴⁺, and O²⁻ ions make significant contributions to the dipole moment, while Ba²⁺, Sr²⁺, and Na⁺ ions contribute relatively less. The findings challenge the conventional view that B-site cation displacements are the primary cause of polarization in perovskite-structured ferroelectrics. The study provides new insights into the polarization mechanisms in BST246 and highlights the importance of understanding structural changes and polarization mechanisms in relaxor ferroelectrics for tailoring and optimizing such materials for various applications.This study investigates the origin of polarization in bismuth sodium titanate-based ceramics, specifically 0.2(Ba0.4Sr0.6TiO3)-0.8(Bi0.5Na0.5TiO3) (BST246). The research reveals that Ti⁴+ contributes less than a third to the overall polarization, while displacements of O²⁻ ions and A-site cations, particularly Bi³⁺, are significant. The analysis of the ferroelectric transition in this system provides insights into understanding such transitions in other ferroelectric perovskites, especially those containing lone pair elements. BST246 exhibits a coexistence of tetragonal and cubic phases at room temperature, allowing for a direct comparison between polar and nonpolar structures. The study shows that the polarization is influenced by the displacement of atoms, with Bi³⁺ ions showing a significant off-center displacement. The research also highlights the role of polar nanoregions (PNRs) in the relaxor ferroelectric behavior of BST246. The study uses high-resolution neutron diffraction, ab initio calculations, and electrical measurements to analyze the structural and electrical properties of BST246. The results show that the tetragonal and cubic phases have similar free energies, and the material exhibits nonergodic relaxor ferroelectric behavior at lower temperatures and ergodic behavior at higher temperatures. The depolarization temperature (Td) of BST246 is around 110 °C, corresponding to a transition from nonergodic to ergodic states. The study also reveals that the displacement of Bi³⁺ ions is significant, contributing a major part to the total A-site contribution to the dipole moment. The overall dipole moment is calculated using the Berry phase approach, showing that Bi³⁺, Ti⁴⁺, and O²⁻ ions make significant contributions to the dipole moment, while Ba²⁺, Sr²⁺, and Na⁺ ions contribute relatively less. The findings challenge the conventional view that B-site cation displacements are the primary cause of polarization in perovskite-structured ferroelectrics. The study provides new insights into the polarization mechanisms in BST246 and highlights the importance of understanding structural changes and polarization mechanisms in relaxor ferroelectrics for tailoring and optimizing such materials for various applications.