Theoretical study of SH-wave propagation in periodically-layered piezomagnetic structure

• The dispersion equation and transmission coefficients of SH wave are derived analytically.
• The piezomagnetism enhances the velocity and reduces the critical angle of the incidence.
• The primary mode turns to dispersion after the magnetic circuit is switched from closed to open.
• Band structures of the piezomagnetic phonon change along with the magnetic circuit.

In this paper, the propagation of SH (shear horizontal) wave in the periodically-layered piezomagnetic structure is studied theoretically. Both the dispersion equation and transmission coefficients are derived to reveal the wave behavior when the piezomagnetism is ignored or the magnetic circuit is closed and open. The zero-order mode of the piezomagnetism-ignored single layer is not dispersive and every higher order mode is dispersive with a cut-off frequency. Same features are found for the closed and open cases, except that the zero-order mode of the latter case is dispersive. The pass bands of the piezomagnetism-ignored periodically-layered structure appear when the normalized frequency is an even integer under the normal incidence, and new stop bands will appear from the pass bands when the incident angle increases. Same features are observed for the band gaps of the magnetically closed and open cases, except that the zero-order mode of the latter case is dispersive.