Monoclinic M_B phase and phase instability in [110] field cooled Pb(Zn_(1/3)Nb_(2/3))O_3-4.5%PbTiO_3 single crystals

摘要

We report the finding of a monoclinic M_B phase in Pb(Zn_(1/3)Nb_(2/3))O_3-4.5%PbTiO_3 single crystals. High precision x-ray diffraction investigations of [110] field cooled crystals have shown a transformation sequence of cubic(C)→tetragonal(T)→orthorhombic(O)→monoclinic(M_B), which is different from that previously reported [A.-E. Renault et al, J. Appl. Phys. 97, 044105 (2005)]. Beginning in the zero-field-cooled condition at 383 K, a rhombohedral (R)→M_B→O sequence was observed with increasing field. Coexisting M_B and O phases were then found upon removal of field, which fully transformed to M_B on cooling to room temperature.