Intermediate ferroelectric orthorhombic and monoclinic M-B phases in [110] electric-field-cooled Pb(Mg1/3Nb2/3)O-3-30%PbTiO3 crystals

Structural phase transformations of [110] electric-field-cooled Pb(Mg1/3Nb2/3)O-3-30%PbTiO3 (PMN-30%PT) crystals have been performed by x-ray diffraction. A phase sequence of cubic (C)-> tetragonal (T)-> orthorhombic (O)-> monoclinic (M-B) was found on field cooling (FC); and a rhombohedral (R)-> M-B-> O sequence was observed with increasing field, beginning from the zero-field-cooled condition at room temperature. The application of the [110] electric field induced a dramatic change in the phase sequence in the FC condition, compared to the corresponding data for PMN-30%PT crystals in a [001] field, which shows that the phase sequence in the FC condition is altered by the crystallographic direction along which a modest electric field (E) is applied. Only when E is applied along [110] are intermediate O and M-B phases observed.