B-site ordering and dielectric relaxation properties of lead magnesium niobate

The mechanism of order-disorder of Lead Magnesium Niobate on B-site was exa mined by both the heat treatment and La+3-doping methods. Pyrochlore phase appeared with the increase of La+3-doping concentration was also studied. T he effect on dielectric properties, such as the increase of degree of diffu se phase transition in both the annealed and La+3-doped specimen, was inter preted as a formation of Mg2+/Nb5+=1 non-stoichiometric short-range ordered micro-domains accompanied with segregation of Nb5+ in the disordered area. It was demonstrated that kinetic mechanism of growth of ordered micro-doma ins was controlled by ion diffusion during both the annealing and La+3-dopi ng.