A study on diffuse antiferroelectric-paraelectric phase transition in pseudobinary Pb(Fe1/2Nb1/2)O3-xPb(Mg1/2W1/2)O3 solid solution

Abstract

An antiferroelectric-paraelectric diffuse phase transition in pseudobinary (1−x)Pb(Fe1/2Nb1/2)O3-xPb(Mg1/2W1/2)O3 solid solution for 0.60≤x≤1.00 is investigated by its dielectric property and calorimetric measurements. The dielectric constant shows a diffuse phase transition behavior for 0.60 ≤x≤0.88, but shows a sharp phase transition behavior for 0.90≤x≤1.00. The apparent dielectric transition temperature increases with increasing external frequency for 0.60≤x≤0.88, but remains constant with respect to the change in external frequency for 0.90≤x≤1.00. Dielectric curves as a function of temperature show broadened peaks for 0.60≤x≤0.88, but show relatively sharp peaks for 0.90≤x≤1.00. The transition enthalpy change also increases with increasing x. The diffuse phase transition for 0.60≤x≤0.88 is accompanied by a small enthalpy change. The small enthalpy difference between the antiferroelectric and paraelectric phases seems to lower the barrier between the two phases, and in the process, the diffuse phase transition seems to be induced.