Rhombohedral and tetragonal nanotwin domains and thermally induced phase transformations in PZN-8%PT single crystals

Phase transformations of unpoled (annealed) and annealed-and-poled 0.92Pb(Zn_1/3Nb_2/3)O₃-0.08PbTiO₃ (PZN-8%PT) single crystals have been examined by combined bulk property characterization and high-resolution x-ray diffraction studies. The results show that at room temperature both unpoled and poled PZN-8%PT single crystals are in the rhombohedral state with a mixture of microscopic (R) and nanotwin (R _NT) domains. Both crystals undergo a R(+R_NT)-T(+T _NT)-C transformation sequence upon zero-field heating (ZFH), where T and C denote the tetragonal and cubic phases, respectively, and T_NT is a brief tetragonal nanotwin state.