LAUSR

The electrical properties and polarization fatigue of [001]-oriented 6Pb(Sc1/2Nb1/2)O3-70Pb(Mg1/3Nb2/3)O3-24PbTiO3 (6PSN-70PMN-24PT) crystals were investigated. Compared with binary Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) crystals, the ternary 6PSN-70PMN-24PT crystal showed a higher rhombohedral → tetragonal transition temperature (TR-T = 120°C) and a larger coercive field (Ec = 4 kV/cm). It was found that the piezoelectric constant (d33 ≈ 1200 pC/N) and electromechanical coupling coefficient (kt ≈ 61%) were weakly dependent on the thermal annealing temperature (Ta), maintaining over 90% of the original value at Ta < 120°C, indicating excellent piezoelectric thermal stability. Electric fatigue measurements showed that the ternary 6PSN-70PMN-24PT crystal exhibited slight fatigue characteristics below 105 bipolar cycles, while the binary PMN-PT crystal exhibited sudden polarization degradation when the cycle numbers were above 102 cycles. The improved fatigue stability for 6PSN-70PMN-24PT crystals was attributed to the large coercive field. The physical mechanisms of the enhanced coercive field and high transition temperature were discussed based on repulsive energy and polar domains.