Improved ferroelectric properties of Ba(Ti,Fe)O₃ ceramics with tiny content of Fe3+doping

BaTiO₃ ceramics were synthesized via a conventional solid-state reaction method to investigate the influence of lattice strain induced by tiny content of Fe3+ doping (1 mol%) on the structural evolution and ferroelectric properties. The incorporation of Fe3+ introduces a compressive strain field, resulting in a reduced c/a ratio and a disordered domain configuration. Such lattice strain significantly enhances the maximum ferroelectric polarization (P_max) from 23.2 μC/cm2 for undoped BaTiO₃ ceramic to 40.6 μC/cm2 for BaTi_0.99Fe_0.01O_3-δ ceramic. This observed enhancement is attributed to a lowered energy barrier for polarization switching and the facilitation of domain wall motion. Phenomenological analysis based on symmetry-related strain-polarization coupling further reveals that the Fe3+ induced compressive strain mitigates the lattice mismatch stress at domain boundaries and alleviates the strain constraint on polarization switching. These findings clarify the relationship between chemical-doping-induced lattice strain and ferroelectric performance, offering a pathway for the deliberate control of domain structure to achieve high ferroelectric performance in bulk ceramics.