Antiferroelectric-like double hysteresis loops in Ag-doped K0.5 Na0.5NbO3 ceramics

In this work, we report the effect of Ag + doping on the microstructure, dielectric, ferroelectric, piezoelectric, and energy storage properties of the K 0.5 Na 0.5 NbO 3 (KNN) ceramics for which (K 0.5 Na 0.5 ) (1-x) Ag x NbO 3 (KNN-xAg) ceramics with x = 0, 0.01, 0.02 and 0.03 were prepared by the conventional solid-state method. The substitution of Ag + changes the microstructure of KNN from inhomogeneous bimodal grain distribution to homogeneous densely packed grains with an average grain size of 0.5–2.25 μm. The phase transition ( T C ) of KNN shifts towards the lower temperature side with Ag + doping. Antiferroelectric-type double PE loops were observed in Ag-doped KNN ceramics at room temperature, which has improved the energy storage and piezoelectric properties of KNN. For ceramics poled at 2 kV/mm for 30 min, a d 33 value of ∼149 pC/N and k p ∼0.41 were obtained. These enhanced properties in Ag-doped KNN are due to the occurrence of double polarization hysteresis loops. • High purity (K 0.5 Na 0.5 ) 1-x Ag x NbO 3 ceramics were synthesized via solid state route. • Phase transition ( T C ) of KNN shifts towards the lower temperature side with Ag + doping. • Anti-ferroelectric like P-E loops were obtained with addition of Ag in KNN ceramics. • Reduced leakage current and improved energy storage performance were found in KNN-xAg ceramics. • Large d 33 ∼ 149 pC/N and k p ∼0.41 were obtained for x = 0.03 KNN-xAg ceramic.