Effect of La on piezoelectric properties of Pb(Ni1/3Sb2/3)O3-Pb(ZrTi)O3 ferroelectric ceramics

Piezoceramic compositions Pb1-zLaz(NiSb)(0.05)[(Z(r0.52)Ti(0.48))(1-Z/4)](0.95)O-3 with Z = 0.01-0.05 were synthesized by mixed oxide route to study the effect of Lanthanum (La) on crystal structure, microstructure, piezoelectric and ferroelectric properties. Calcination was performed at 1,060 degrees C and sintering at 1,270 degrees C for 1 h. X-Ray diffraction pattern indicated the polycrystalline microstructure along with co-existence of tetragonal and rhombohedral perovskite phases. Dielectric constant (K-3(T)) was increased whereas piezoelectric voltage constant (g(33)) was decreased with increase in lanthanum. Dense microstructure was observed for the composition containing 3 mol% of lanthanum. This was resulted in optimum piezoelectric charge constant (d(33) = 468 x 10(-12) C/N), electromechanical coupling factor (k(p) = 0.68), remanent polarization (P-r = 24.65 mu C/cm(2)) and displacement (D = 2,012 nm). Results indicated that the composition Pb0.97La0.03(NiSb)(0.05)[(Zr0.52Ti0.48)(0.9925)](0.95)O-3 could be suitable for actuator applications. The composition Pb0.98La0.02(NiSb)(0.05)[(Zr0.52Ti0.48)(0.995)](0.95)O-3 resulted into moderately high value of voltage constant (g(33) = 39.3 x 10(-12) V m/N) and optimum value of Figure of Merit (d(33) x g(33) = 16.2 x 10(-12) C V m/N-2) indicated the usefulness for sensor and power harvesting applications.