Effects of composition on phase structure and electrical properties of (K0.5Na0.5)0.90Li0.06Sr0.02Nb(1-x)SbxO3 ceramics

Lead-free (K0.5Na0.5)0.90Li0.06Sr0.02Nb(1-x)SbxO3 (KNLSN-Sbx) ceramics were synthesized by ordinary sintering technique. The compositional dependence of phase structure and electrical properties of the ceramics was systematically investigated. All samples possessed pure perovskite structure, showing room temperature symmetries of orthorhombic at x<0.01, coexistence of orthorhombic and tetragonal phases at x=0.01, and tetragonal at 0.02≤x≤0.05. The temperature of the polymorphic phase transition (PPT) was shifted to lower temperature and dielectric relaxor behavior was induced by increasing Sb content. The samples near the coexistence region (x=0.01) exhibited enhanced electrical properties: d33∼145 pC/N, kp∼38% and Pr∼20.4 μC/cm2.