Dielectric, ferroelectric and piezoelectric properties of (1−x)[K0.5Na0.5NbO3]−x[LiSbO3] ceramics

Lead-free (1−x)[K0.5Na0.5NbO3]−x[LiSbO3] (x=0, 0.04, 0.05 and 0.06)/(KNN-LS) ceramics were prepared by conventional solid-state reaction route (CSSR). For dense morphology pure KNN ceramic was sintered at 1120 °C and LS modified KNN ceramics were sintered at 1080 °C for 4 h, respectively. The structural study at room temperature (RT) revealed the transformation of pure orthorhombic to tetragonal structure with the increase in LS content in KNN-LS ceramics. Temperature dependent dielectric study confirmed the increase of diffuse phase transition nature with the increase in LS content in KNN-LS ceramics. The presence of orthorhombic to tetragonal (TO−T) polymorphic phase transition temperature (PPT) ∼43 °C confirmed the presence of two ferroelectric (orthorhombic and tetragonal) phases in 0.95KNN-0.05LS ceramics at RT. 0.95KNN-0.05LS ceramics showed better ferroelectric and piezoelectric properties i.e., remnant polarization (Pr)∼18.7 Î¼C/cm2, coercive field (Ec)∼11.8 kV/cm, piezoelectric coefficient (d33)∼215 pC/N, coupling coefficient (kp)∼0.415 and remnant strain ∼0.07% were obtained. ⺠Effect of LiSbO3 content on the electrical properties of KNN ceramics within the MPB region. ⺠Optimization of poling temperature to obtain better piezoelectric properties. ⺠Increase of diffuse phase transition nature with the increase in LiSbO3 content. ⺠Temperature dependence of piezoelectric properties have been studied.