Propagation of Shear Horizontal Waves in Laminated Composites Based on Differently Orientated Poled 0.72Pb(Mg_1/3Nb_2/3)O₃-0.28PbTiO₃ Single Crystals

The propagation characteristics of shear horizontal waves in 001_c, 011_c and 111_c direction polarized 0.72Pb (Mg_1/3Nb_2/3)O₃-0.28PbTiO₃ (PMN-0.28PT) piezoelectric single crystals/polymer periodic laminated composites are studied by using the global matrix method. The numerical results show that the piezoelectric effect has a significant influence on the bandgap width of the composite structure containing 011_c and 111_c poled PMN-0.28PT, but little effect on the band structure of the system containing 001_c poled single crystal. In addition, the first bandgap (FBG) width of the composite structure depends strongly on the poling directions when the filling fraction of PMN-0.28PT is larger than 0.5, and its FBG starting frequency displays no distinct difference among the three polarization directions at all filling fractions. The reported results provide valuable guidelines for designing filters and transducers made of composite structures containing relaxor-based ferroelectric single crystals.