Orientation dependence of coupling between Lamb and shear horizontal waves in (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystal plates

The orientation dependence of coupling between Lamb and shear horizontal (SH) waves in [001]
_c
and [011]
_c
poled (1-x)Pb(Mg
_1/3
Nb
_2/3
)O
₃
-xPbTiO
₃
(PMN-xPT) single crystal plates has been studied theoretically. For a [001]
_c
polarized PMN-PT crystals plate there is no coupling between Lamb and SH waves when thetas = npi/4 (n = 0,1, 2, ...),and the strongest coupling occurs when thetas = (2n +1)pi/8 . For a [011]
_c
polarized PMN-PT crystal plate, the decoupling and strongest coupling happen when thetas = npi/2 and thetas = (2n +1)pi/4 , respectively. Guided wave propagation for coupled and decoupled cases and for symmetric and antisymmetric modes are calculated explicitly. The results are useful for the design of guided wave devices using PMN-xPT single crystals.