Phase coexistence and transformations in field-cooled ternary piezoelectric single crystals near the morphotropic phase boundary

摘要

Structural phase transformations in (100)-oriented Pb(In_(1/2)Nb_(1/2))O_3-Pb(Mg_(1/3)Nb_(2/3))O_3-PbTiO_3 single crystals have been investigated by X-ray diffraction. A cubic (C) → tetragonal (T) → monoclinic-C (M_C) transformation sequence was observed in the field-cooled condition. Two phase coexistence regions of C + T and T + M_C were found. In addition to an increase in the C → T phase transition temperature and a decrease of the T→ M_C one, a broadening of the coexistence regions was also found with increasing field. This broadening can be explained by the presence of polar nano regions within the C, T, and M_C phase regions.