Temperature-induced and electric-field-induced phase transitions in rhombohedral Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ternary single crystals

Temperature and electric field effects on rhombohedral (R) ternary Pb(In1/2Nb1/2)O-3-Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PIN-PMN-PT) ferroelectric single crystals were comprehensively studied by x-ray diffraction. We have focused on how the individual phase transitions as well as the phase transition sequences depend on thermal and electrical history. Electric field-temperature phase diagrams have been constructed under [001] field-cooling and field-heating conditions. As happens to the R phase of binary PMN-PT crystals [H. Cao, J. F. Li, D. Viehland, and G. Y. Xu, Phys. Rev. B 73, 184110 (2006)], the R phase of the zero-field-cooled (ZFC) state is replaced by a monoclinic A (M-A) phase in the field-cooled (FC) diagram. In particular, reciprocal-space mesh scans demonstrated that the M-A phase was stable for crystals poled along the [001] crystallographic direction rather than the initial R phase of the ZFC state. Furthermore, an E-field-induced phase transformational sequence of R -> M-A -> tetragonal (T) was observed at constant temperature, revealing a gradual increase in the c lattice parameter. These findings demonstrate that the ternary PIN-PMN-PT crystals exhibit common phase transition features with binary PMN-PT and Pb(Zn1/3Nb2/3)O-3-PbTiO3 (PZN-PT) ones for compositions in the low PT side of the morphotropic phase boundary.