Phase transition in Pb[(Mg3/4Cu1/4)1/3Nb2/3]O3 ceramic

Single phase perovskite-type cubic ceramics of Pb[(Mg 3/4 Cu 1/4 ) 1/3 Nb 2/3 ]O 3 (PMCN) were synthesized by high temperature double step solid state reaction technique. Dielectric studies show relaxor behaviour with diffuse phase transition. The phase transition (T m ) occurs at -22°C at 10 kHz. The frequency dependence of T m has been modeled using Vogel-Fulcher relation. The dielectric relaxation in PMCN is found analogous to the magnetic relaxation in spin-glass system. The relaxor behaviour in PMCN has also been examined through admittance spectroscopy.