Full tensor properties of [111](c) poled (Na, K)(Nb,Ta)O-3 lead-free single crystal

摘要

Complete sets of elastic, piezoelectric and dielectric constants of [111](c) poled (Na,K)(Nb, Ta)O-3 single crystal have been measured. The results show that the crystal with "3O" domain structure exhibits high shear but low longitudinal piezoelectric properties (d15=140 pC/N, k(15)=0.569, d(33)=64 pC/N and k(33)=0.450), which is similar to the "1O" single domain state, but different from the "4O" multi-domain state. The orientation-dependent longitudinal properties, e.g., d*(33), epsilon*(33), s*(33) and K*(33) in the (0 (1) over bar1)(c) plane have been calculated. The maximum piezoelectricity exists at the position of 38 degrees away from [011](c), which is close to the [111](c) direction. By comparing the measured and calculated parameters, it can be concluded that the piezoelectricity is dominated by the intrinsic contribution while the dielectricity is controlled by the extrinsic contributions.