The specific features of the coexistence of phases in heavily twinned crystals of the (1−x)Pb(Mg1/3Nb2/3)O3−xPbTiO3 system in the vicinity of the morphotropic phase boundary (0.30 ≤ x ≤ 0.40) were investigated. The phase transformations in crystals with x = constant during cooling were considered for electric field strengths of 0 and 0.1MV/m. The conditions for the formation of interphase boundaries (zero net strain planes) were determined for various first-order phase transitions. The results of calculating the tetragonal-monoclinic MC and monoclinic-monoclinic (MC–MA) phase transitions were represented in the form of so-called twin state-interphase boundary diagrams. The effect of a 90° domain (twin) structure of the tetragonal phase upon the heterophase state associated with the presence of monoclinic phases was analyzed.

Comparative Analysis of the Twin and Heterophase Structures in (1−x)Pb(Mg1/3Nb2/3)O3−xPbTiO3 Crystals. V.Y.Topolov: Physics of the Solid State, 2006, 48[7], 1334-41