Dielectric and piezoelectric properties of ZnO and SnO2 co-doping K0.5Na0.5Nbo3 ceramics

Abstract

Abstract A series of (1− x )K 0.5 Na 0.5 NbO 3− x (ZnO and SnO 2 ) ceramics were prepared by solid state reaction method and their structures, dielectric and piezoelectric properties were investigated. All samples show pure perovskite phase with typical orthorhombic symmetry at x ≤0.6%. However, a trace amount of ZnSnO 3 was detected at x ≥0.8%, in addition to the ZnSnO 3 , some Zn 2 SnO 4 and SnO 2 were presented at x ≥1.0%. The phase transition temperature of orthorhombic–tetragonal ( T O − T ) and tetragonal–cubic ( T c ), the remnant polarization ( P r ) and the coercive field ( E c ) decreased with increasing x . The dielectric constant ( e r ), piezoelectric constant ( d 33 ) and electromechanical coupling factor ( k p ) increased with increasing x until x =0.8%, and then decreased with further increasing x . And the optimum piezoelectric properties of e r =503, d 33 =124 pC/N and k p =0.398 were obtained. The increase in piezoelectric properties might be due to the increase in density and ZnSnO 3 doping.