Dielectric and piezoelectric enhancement in lead-free Bi0.5Na0.5TiO3 ceramics by incorporating BaTiO3

X-ray diffraction confirmed the formation of BNT–xBT solid solutions and a structural transition from rhombohedral to tetragonal symmetry. Frequency-dependent dielectric measurements showed a notable increase in relative permittivity, reaching 1750, over twice that of undoped BNT.

This enhancement is linked to the formation of polar nanoregions (PNRs), which boost dielectric susceptibility through localized polarization. Temperature-dependent analysis revealed a broadened permittivity peak and diffuse phase transition, indicating disrupted long-range ferroelectric order and growing PNR activity. Polarization–electric field (P–E) loops showed a reduction in coercive field from ~ 60 kV/cm in pure BNT to ~ 23 kV/cm in BNT-BT modified samples, due to the coexistence of PNRs and ferroelectric domains, facilitating polarization switching and resulting in slim hysteresis loops.