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 degrees C and LS modified KNN ceramics were sintered at 1080 degrees 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) similar to 43 degrees 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 (P-r)similar to 18.7 mu C/cm(2), coercive field (E-c)similar to 11.8 kV/cm, piezoelectric coefficient (d(33))similar to 215 pC/N, coupling coefficient (k(p))similar to 0.415 and remnant strain similar to 0.07% were obtained. (C) 2012 Elsevier Ltd. All rights reserved.