Sub-switching domain effect for analysis the non-linear dielectric behavior of (K0.49 Na0.49Li0.02) (Nb0.98Sb0.02)O3 ceramic based on Rayleigh model

The solid-state sintering technique has been implemented to synthesize (K0.5Na0.5NbO3)-0.02(LiSbO3) (KNN-LS) Pb-free ceramic. The crystal structure, dielectric and ferroelectric properties of the prepared material were investigated. Pure orthorhombic perovskite phase [I-(220)/I-(002) = 1.68] with Amm2 space group has been detected at room temperature for sintered ceramic. Two anomalous permittivity peaks corresponding to orthorhombic-tetragonal (O-T) phase transition at T = 175 degrees C and tetragonal-cubic (T-C) phase transition at T = 355 degrees C have been observed. At polymorphic phase transition, the Rayleigh model shown the extrinsic contributions caused by domain wall motion is about 80%, while the intrinsic contribution attributed to the lattice distortion is about 20%. Ferroelectric properties were investigated in a wide range of temperatures (RT-225)degrees C. The results shown a conductive material at high temperature due to the higher cation disorder and leakage current above PPT. The present results are interested for understanding the mechanism of t permittivity-temperature behavior of KNN-doped LS ions based on Rayleigh model. The large remnant polarization and low coercive field below PPT make the material a suitable candidate for energy storage application.