Propagation of the Bleustein–Gulyaev waves in a functionally graded transversely isotropic electro-magneto-elastic half-space

Bleustein–Gulyaev (B–G) waves in a functionally graded transversely isotropic electro-magneto-elastic half-space, in which all parameters exponentially change along the depth direction, are investigated, and the dispersion equations with respect to the phase velocity for electromagnetically open and shorted conditions are obtained. The B–G waves are dispersive because of the inhomogeneity of the material, which is different from a pure substrate. The graded coefficient exhibits different effects on the B–G waves at different electromagnetic circumstances. With the intervention of the functionally graded material, the electro-magneto-mechanical coupling factor can be improved and the penetration depth of the B–G waves can be decreased. The results can be used in the design of high-performance surface acoustic wave devices.