Diffuse phase transition in Ca-modified Pb(Li1/4La1/4Mo1/2)O-3 ferroelectric ceramics

Polycrystalline samples of (Pb1-xCax)(Li1/4La1/4Mo1/2)O-3, x = 0.00, 0.03, 0.07, 0.10, were prepared by solid-state reaction technique. The formation and quality of the compounds were checked by preliminary X-ray studies. Det ailed studies of dielectric properties (constant and loss) and hysteresis l oop as a function of temperature suggest that these compounds undergo ferro electric diffuse phase transition. The substitution of Ca2+ ion at Pb2+ sit es causes a major effect on their transition temperature and electrical pro perties. Measurements of de resistivity as a function of temperature and bi asing de electric field suggest that the compounds have negative temperatur e coefficients of resistance (NTCR) above room temperature. (C) 1999 Elsevi er Science Ltd. All rights reserved.