Dual structures and transition regions in xPbTiO3-(1−x)Pb(Zn1/3Nb2/3)O3 crystals

Model concepts of dual structures are developed as applied to crystals of xPbTiO3-(1−x)Pb(Zn1/3Nb2/3)O3 solid solutions in the range 0 ≤ x ≤ 0.08. The conditions of the formation of dual structures upon partial and complete relaxation of internal mechanical stresses are considered. A new model of transition regions is proposed for analyzing several variants of changing the unit cell parameters that satisfy the condition of complete stress relaxation inside the transition regions in crystals at concentrations x = 0.045 and 0.08. The influence of the intermediate phase P4mm and stability of its 90° domain structure on the formation of dual structures at x ≥ 0.045 is discussed.