Evolution of Phononic Band Gaps in One-Dimensional Phononic Crystals that Incorporate High-Tc Superconductor and Magnetostrictive Materials

In this work, we calculate the reflectance of one-dimensional phononic crystals (1D PnCs) using the transfer matrix method. We present numerical results for two different PnC structures, the first one, PnCs1, contains high-T-c superconducting compound (Bi-2223) and the second, PnCs2, contains a giant magnetostrictive material (Terfenol-D). Magnetostriction is a property of ferromagnetic materials that causes them to change their shape/dimensions when subjected to external magnetic field. PnC studies that dealt with such materials are few. In this study, we focus on discussing the effects of the temperature and the magnetic field on the phononic gaps of these PnCs. For PnCs1, numerical results show that local resonant modes of elastic waves with brilliant sharpness can be realized. In addition, increasing the temperature leads to a decrease in the gap width which can be controlled by the magnetic field due to the effect of the magnetic field on the velocity of waves in the high-T-c superconducting compound, the magnetic field effectively can widen the gap. For PnCs2, numerical results show that the gap width increases by increasing the magnetic field because the magnetostrictive material directly expanded in the presence of the magnetic field.