Internal resonances in a periodic magneto-electro-elastic structure

Propagation of electro-magneto-acoustic waves in a three phase magneto-electro-elastic periodic structure has been investigated with full coupling between mechanical, electric, and magnetic fields. Due to simultaneous piezoelectric and piezomagnetic effects, an orthogonally polarised electromagnetic wave couples with the similarly polarised lattice vibration, resulting in a both dielectric and magnetic phonon-polaritons. The closed form of dispersion relation has been used to demonstrate the phonon-polariton coupling not only in the long wave region at high acoustic microwave frequencies but also for shorter waves at optical infrared frequencies. The results also show that neither at acoustic nor at optical frequencies the magneto-electro-elastic effect affects the band structure due to the Bragg scattering. (C) 2014 AIP Publishing LLC.