Cluster glass like behavior of magnetoelectric PbNi1/3Nb2/3O3 ceramics

Dielectric properties of single phase PbNi1/3Nb2/3O3 (PNN) ceramic prepared by two step coulmbite method has been investigates thoroughly. The value of degree of relaxational constant ΔTm ∼24, and diffuseness parameter calculated from the modified Curie-Weiss fitting δA ∼111, suggests higher dielectric relaxation strength for PNN in comparison to well-known PbMg1/3Nb2/3O3 PMN. Frequency dependence of temperature of dielectric maximum (e’m) is fitted with Arrhenius, Dipolar glass, stretched exponential and cluster glass model. The attempt frequency of physically acceptable process has been obtained from cluster glass model, which indicates critical slowing down of PNR dynamics.