Unique Dielectric Behavior of 0.6Pb(Ni_1/2W_1/2)O₃·0.4PbTiO₃ Derived from Mechanical Activation

Abstract

0.6Pb(Ni 1/2 W 1/2 )O 3 ⅐0.4PbTiO 3 (0.6PNW⅐0.4PT) 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 PbTiO 3 arising from mechanical activation. The dielectric behavior can be fine tuned by thermal annealing at 750°C, leading to phase redistribution in PNW-PT.