Neutron diffraction study of domain structures in poled and unpoled PZN–4.5%PT

Neutron diffraction was used to investigate the evolution of the domain structure in PZN–4.5%PT during cooling in zero field and in a 〈0 0 1〉 poling field. The use of neutron diffraction allows penetration below the thick skin layer that has presented significant problems for earlier X-ray studies. We have confirmed the existence of a tetragonal phase existing between the cubic and rhombohedral phases, and that a poling field of 500 V/cm along 〈0 0 1〉 is sufficient for a cubic to tetragonal phase transition to occur. In the absence of a poling field we find that a “Phase X” behaviour occurs on cooling from the cubic phase. However, once the cubic to tetragonal phase transition has occurred the poling field can be removed and the phase transition to the rhombohedral phase will occur on further cooling. As expected, the domain structure of the tetragonal phase contains 90° twins and the dominant domain orientation is with the spontaneous polarization along the 〈0 0 1〉 poling field.