Variation of di-/piezoelectric properties of PIN-PMN-PT crystals near morphotropic phase boundary along the growth direction

25Pb(In_1/2Nb_1/2)O₃-45Pb(Mg_1/3Nb_2/3)O₃ -30PbTiO₃ (PIN-PMN-PT) ingots with the dimensions of Ø55×130mm were successfully grown by vertical Bridgman technique. The as-grown PIN-PMN-PT crystals were oriented and characterized on (001) cuts. Variation of di-/piezoelectric properties of the as-grown PIN-PMN-PT crystals near morphotropic phase boundary (MPB) along the growth direction were investigated. Temperature dependence of dielectric permittivity advised 60~135°C of rhombohedral to tetragonal phase transition temperature (T_rt) and 120~210°C of Curie temperature (T_c) near MPB along the growth direction. PIN-PMN-PT crystals have coercive fields (E_c) of about 4.35kV/cm, more than twice that of Pb(Mg_1/3Nb_2/3)O₃-32PbTiO₃ (PMN-PT) and about 1% electric field strain. T_c was found to increase linearly along the growth direction and T_rt gradually decreased in the middle part of the ingot. The piezoelectric constant, d₃₃, increased initially then kept around 2000pC/N at lower but near MPB and the dielectric constant, ε_r, had the same trend with d₃₃ falling into the scope of 5000-6300.