Frequency response analysis by finite element method in relaxor single-crystal plates with giant k31

Plate resonators (dimensions: 13(L) x 4.0(w) x 0.36(T) mm(3)) composed of relaxor single-crystal plates with a giant k(31) (> 80%) in Pb[(Zn1/3Nb2/3)(0.91)Ti-0.09]O-3 (PZNT91/09) with the (100) plane and Pb[(Mg1/3Nb2/3)(0.74)T-0.26]O-3 (PMNT74/26) with the (110) plane were investigated regarding their vibration modes in the directions of length (k(31) mode) and width (k(32) mode). Frequency response analysis of impedance on the giant k(31) mode was evaluated by a finite element method (FEM) and the simulated data by FEM were compared with the measured results. A large anisotropy of the Poisson ratio of the length direction (sigma(E)(L)) and the width direction (sigma(E)(W)) was observed and the ratios of sigma(E)(W) /sigma(E)(L) reached 3.2-3.4 in the PZNT91/09 single-crystal plates and 4.5-4.9 in the PMNT74/26 single-crystal plates. Although sigma(E)(W)/sigma(E)(L) was fixed at 3.2 (PZNT91/09) and 4.9 W (PMNT74/26), sigma(E)(L) and sigma(E)(W) were further changed; the simulated data were well fitted to the measured data in the cases of the PZNT91/09 and PMNT74/26 single-crystal plates. In the PZNT91/09 single-crystal plates, the Poisson ratio on the k(31) and k(32) modes affected the frequency response of impedance in the k(t) mode, which corresponds to thickness vibration of the plate. However. the Poisson ratio in the PMNT74/26 single-crystal plates was independent of the frequency response of impedance in the k(t) mode. Moreover, the domain behavior of the PZNT91/09 single-crystal plates could be explained by the simulated impedance responses on the third overtone of the k(31) fundamental vibration.