Effect of poling temperature on piezoelectric and dielectric properties of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals under alternating current poling

In this work, the piezoelectric and dielectric properties of [001]-oriented 0.7Pb(Mg1/3Nb2/3)O-3-0.3PbTiO(3) single crystals under alternating current poling (ACP) at different temperatures were studied. The piezoelectric coefficients (d(33) similar to 1930 pC/N, d(31) similar to -850 pC/N) and free dielectric permittivity (epsilon(T)(33)/epsilon(0) similar to 7570) reached their highest values when the poling temperature (T-poling) was 70 degrees C. Compared with traditional direct current electric field poling at 20 degrees C, 70 degrees C-ACP samples showed an enhancement of 40%, 35%, and 49% for d(33), d(31), and epsilon(T)(33)/epsilon(0), respectively. Meanwhile, d(33) and epsilon(T)(33)/epsilon(0) were enhanced by about 9% when T-poling increased from 20 degrees C to 70 degrees C under ACP, while d(31) remained the same value and the dielectric loss was lowered from 0.29% to 0.22%. Moreover, ACP samples with different T-poling have similar electromechanical coupling factors (k(31) similar to 0.44, k(t) similar to 0.60). A discussion of the mechanism for the ACP enhancement was based on the domain observation using piezoresponse force microscopy, and the results showed that the domain densities of ACP samples with different T-poling were positively correlated with their piezoelectric properties. This work demonstrated the enormous potential of ACP optimization for relaxor-PT single crystal applications. Published under license by AIP Publishing.