Structure and the location of the morphotropic phase boundary region in (1-x)[Pb(Mg_1/3Nb_2/3)O₃]-xPbTiO₃

Abstract

The structure of (1-x)[Pb(Mg1/3Nb2/3)O3]-xPbTiO3 is tetragonal and rhombohedral for x⩾0.35 and x⩽0.30, respectively. The intrinsic width of the morphotropic phase boundary region (0.30<x<0.35) is an order of magnitude smaller than hitherto believed. The structure of the morphotropic phase for x = 0.34 is shown to be monoclinic with space group Pm and not a mixture of rhombohedral and tetragonal phases.

Strain on ferroelectric thin films

“…Instead of a line, a boundary, a morphotropic phase region was established circa 2000. This region is characterized by monoclinic symmetries: Cm [10][11][12][13], Cc [14,15], and Pm [16,17], either alone or coexisting with the neighboring rhombohedral and tetragonal symmetries. These monoclinic phases are considered to act as a structural bridge between the rhombohedral and tetragonal sides of the phase diagram, enabling the rotation of the polarization within the monoclinic plane [18][19][20].…”

Role of the TiO6 octahedra on the ferroelectric and piezoelectric behaviour of the poled PbMg1/3Nb2/3O3–xPbTiO3 (PMN–PT) single crystal and textured ceramic

“…According to the X-ray diffraction the high temperature symmetry is cubic with the Pm3m space group [9][10][11][12][13][14][15][16][17][18]. As we already mentioned for such symmetry the first order Raman activity is forbidden.…”

“…It must be stressed that the excellent electromechanical properties and the giant piezoeffect are A c c e p t e d m a n u s c r i p t 4 observed for the solid solutions with compositions belonging to the MPB. In general, these materials posses already ferroelectric behaviour and undergo the monoclinic (Pm) -> tetragonal (P4mm) -> cubic (Pm3m) structural phase transitions [11,12]. However, many authors [11,[13][14][15][16][17] suggested that the symmetry observed in the vicinity of the MPB is more complex.…”

Three intrinsic relationships of lattice parameters between intermediate monoclinicMCand tetragonal phases in ferroelectricPb[(Wang1 2006Phys. Rev. B771200View full textAdd to dashboardCite

“…Recent extensive experimental investigations have discovered new intermediate phases and revealed fascinating while puzzling phase behaviors around the MPBs. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Since the recent discovery of an intermediate monoclinic M A phase in PZT near its MPB, [23][24][25][26][27][28] new intermediate phases have also been discovered in PZN-xPT and PMN-xPT near their respective MPBs, namely, monoclinic M A , [8][9][10] monoclinic M C , [8][9][10][11][12] orthorhombic ͑Refs. 8 and 13-15͒ phases in PZN-xPT, and orthorhombic, 16,17 monoclinic M C , 12,[18][19][20][21] monoclinic M A , 21,22 as well as a third monoclinic M B phase ͑Refs.…”

“…The recently established temperature-composition phase diagrams 15,19 and electric-field-temperature phase diagrams 10,21 reveal some fundamental aspects of the phase stabilities in the vicinity of MPBs. The large body of reported experimental data [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] provides information to investigate the relations between the phases and to clarify the origin of the ultrahigh electromechanical properties of these materials.…”