Effect of low-frequency alternating current poling on 5-mm-thick 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals

Alternating current (electric field) poling (ACP) was applied on [001]-oriented 0.7Pb(Mg1/3Nb2/3)O-3-0.3PbTiO(3) (PMN-0.3PT) single crystal samples with dimensions of 5 x 1.25 x 1.25 mm(3) (with electrodes on the 1.25 x 1.25 mm(2) surfaces), and the influence of ACP frequency (f(ACP)) was studied. Compared to those from traditional direct (electric field) poling samples, the piezoelectric coefficient (d(33)) and free dielectric constant (epsilon(T)(33)/epsilon(0)) of ACP samples could gain up to a 67% increase to 3200 pC/N and 10 500, respectively. The influence of f(ACP) was studied on two main aspects: saturated properties and dynamic saturation process. In general, ACP samples with lower f(ACP) had higher saturated d(33), epsilon(T)(33)/epsilon(0), and coupling factor k(33), as well as lower dielectric loss and faster saturation speed. The ACP dynamics during the saturation process were studied by measuring the polarization-vs-electric field hysteresis loops (P-E loops). The P-E loops illustrated that the coercive field of ACP samples could be further tuned from 1.84 kV/cm to 3.03 kV/cm by changing f(ACP) (0.1-10 Hz). This work demonstrated the enormous potential of ACP optimization in relaxor-PT single crystal-based low-frequency transducer applications.