Dielectric-State Analysis in Solid-Solution Pb(Yb₁₂Ta₁₂)O₃Pb(Lu₁₂Nb₁₂)O₃

The structure and temperature dependence of complex lead perovskite dielectrics were investigated for the system (1 - x)Pb(Yb1/2Ta1/2)O-3-xPb(Lu1/2Nb1/2)O-3. Superlattice reflections for the compositions 0.8 < x < 1.0 were observed by X-ray diffractometry, and the temperature-composition dielectric-state diagram was determined. In the present study, the disordered middle composition, with 0.2 < x < 0.8, showed a diffuse paraelectric-ferroelectric phase transition, whereas the ordered end compositions, with 0 less than or equal to x < 0.2 and 0.8 < x less than or equal to 1,0, revealed successive sharp paraelectric-antiferroelectric and weak antiferroelectric-ferroelectric phase transitions. The dielectric state was confirmed by examining the variation of polarization (P) with electric field (E).