Investigation of dielectric and piezoelectric properties of niobium-modified PLSZFT nanoceramics for sensor and actuator applications

In this paper, the microstructure, dielectric and piezoelectric properties of pentavalent Nb5+ on isovalent Sr2+ and acceptor Fe3+-modified PLZT have been reported. Nanocrystalline ceramic compositions [Pb0.973La0.012Sr0.015][(Zr0.54Ti0.46)0.9895−(5n/4)Fe0.01Nbn]O3 (PLSZFNT) where n = 0, 0.2, 0.4, 0.6, 0.8 and 1 mol%) near morphotrophic phase boundary were fabricated through solid-state reaction method.X-ray diffraction patterns indicated that pure PLZT showed the presence of rhombohedral phase, and Fe and Sr incorporation into PLZT (PLSZFT) lattice shifted to coexistence of both rhombohedral and tetragonal phases while increasing Nb content in PLSZFT resulted in enhanced tetragonality. The tolerance factor (t = 1.00) indicates an ideal and stable tetragonal structure of PLSZFNT lattice. Grain size and apparent density were maximum at Nb0.01. TEM studies indicated that average particle size ranged from 16 to 63 nm. The effect of grain growth on dielectric and piezoelectric properties were studied. The optimum dielectric and piezoelectric properties were found (ɛRT = 2862, d33 = 491 pC/N and kp = 0.522) in n = 1 mol%, respectively, which could be suitable for possible sensor and actuator applications.