Intermediate ferroelectric orthorhombic and monoclinic M{sub B} phases in [110] electric-field-cooled Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-30%PbTiO{sub 3} crystals

Structural phase transformations of [110] electric-field-cooled Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-30%PbTiO{sub 3} (PMN-30%PT) crystals have been performed by x-ray diffraction. A phase sequence of cubic (C){yields} tetragonal (T){yields} orthorhombic (O){yields} monoclinic (M{sub B}) was found on field cooling (FC); and a rhombohedral (R){yields}M{sub B}{yields}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{sub B} phases observed.