Optimum geometrical structure of highly magnetostrictive multilayer films for horizontally polarized high frequency magneto-surface-acoustic-wave propagation

Optimum geometrical structure of highly magnetostrictive multilayer films for the propagation of horizontally polarized magneto-surface-acoustic-wave (Love-type MSAW) was determined theoretically. The multilayered medium is composed of highly magnetostrictive alloy films and insulating films which are stacked alternately on a glass substrate. The analysis revealed that outstanding magnetoacoustic quantities comparable to those of an ideal nonconductive medium can be realized with the conductive multilayer films whose geometrical parameters meet the following conditions: DM/DL≥1, DM/DI≥10, and N∼20, where N is the number of insulating layers having the whole thickness of DI, and DM is the whole thickness of magnetic layers. DL is a limiting thickness of the magnetic film with a single-layer structure, above which the magnetoacoustic quantities are considerably deteriorated due to the micro-eddy current losses.