Electric-field-induced phase transition in 001 -oriented Pb(Mg1/3Nb2/3)O3-PbTiO3single crystals

⟨001⟩-oriented 0.7Pb(Mg 1/3 Nb 2/3 )O 3 –0.3PbTiO 3 single crystals were poled under two different electric fields, E poling = 4 and 13 kV cm −1 . In addition to the temperature-dependent dielectric constant measurement, x-ray diffraction was also used to identify the poling-induced phase transitions. The results showed that the phase transition significantly depends on the poling intensity. The weaker field ( E poling = 4 kV cm −1 ) was able to overcome the effect of the random internal field to produce the phase transition from the rhombohedral ferroelectric state with short-range ordering (microdomains), FE SRO , to the rhombohedral ferroelectric state with long-range ordering (macrodomains), FE LRO . But the rhombohedral ferroelectric-to-tetragonal ferroelectric phase transition originating from ⟨111⟩ to ⟨001⟩ polarization rotation could only be induced by the stronger field ( E poling = 13 kV cm −1 ). The sample poled at E poling = 4 kV cm −1 showed a higher piezoelectric constant, d 33 ≥1500 pC N −1 , than the sample poled at E poling = 13 kV cm −1 .