Antiferroelectricity in tantalum doped (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free ceramics

Abstract (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 (Ti 1− x Ta x )O 3 ( x =0.00–0.04) lead-free polycrystalline ceramics were synthesized using the solid state reaction route, and their crystal structures and electrical properties were systematically studied. With the introduction of Ta substitution, the relaxor antiferroelectric phase with tetragonal P 4 bm symmetry is stabilized. The representative double polarization hysteresis loops and sprout shaped strain curves for antiferroelectric ceramics are observed at higher Ta contents with x =0.01–0.02 at room temperature. x =0.01 shows the largest strain of 3.81‰ under 60 kV/cm, indicating a good candidate for actuator applications. The polarization and strain hysteresis loops are also evaluated to verify the temperature-induced normal ferroelectric phase to relaxor antiferroelectric phase transition at temperature up to 120 °C. The energy storage density and efficiency at various temperatures are calculated and analyzed in the compositions of x =0.00–0.02. The results indicate that the energy storage density becomes more temperature independent with the increase of Ta concentration, which are promising for applications in high-temperature capacitors.