Unique dielectric behavior of 0.6Pb(Ni1/2W1/2)O3·0.4PbTiO3 derived from mechanical activation

Abstract

0.6Pb(Ni1/2W1/2)O3·0.4PbTiO 3(0.6PNW·0.4PT) of complex perovskite structure is successfully synthesized by mechanical activation of mixed oxide composition, followed by sintering at 950°C. It exhibits a considerably stable temperature dependence of dielectric constant over the wide temperature range of -120° to 20°C, although there occurs a dielectric peak at around 74°C. Raman spectroscopic studies show the coexistence of tetragonal and pseudocubic perovskite phases on sintering at 950°C, which are attributed to the inhomogeneous distribution of PbTiO3 arising from mechanical activation. The dielectric behaviour can be fine tuned by thermal annealing at 750°C, leading to phase redistribution in PNW-PT.