Study of the phonon-polaritons in piezomagnetic superlattices using a generalized transfer matrix method

Piezomagnetic materials are characterized by strong coupling between magnetization and acoustic vibration and the piezomagnetic coefficients change sign with respect to domain polarization. For piezomagnetic superlattices (PMSL) with periodically up and down polarized domain structures, the piezomagnetic coefficients are modulated periodically, and the resulting phonon-polaritons form a band-like structure. This study, using the generalized transfer matrix method, shows that a polariton-like band-gap can be realized in piezomagnetic material with the 6mm point group under a certain configuration of magnetic field, lattice displacement and domain polarization, but the mid-gap frequency is restricted to the range of a few GHz or below if the domain wall effect is taken into consideration.