Guiding magnetostatic surface waves with nonuniform in-plane fields

We report the propagation characteristics of magnetostatic surface waves in a rectangular yttrium iron garnet film placed between strips of mumetal and in the plane of the strips. The microstrip excitation structure was designed so as to permit the strips to extend along the entire path of propagation, thereby minimizing field nonuniformities in the longitudinal direction. These experiments suggest that nonuniform in-plane fields can be used to alter the dispersion characteristics of the waves. A theoretical argument is also presented describing a possible energy localization mechanism in nonuniform in-plane fields. In addition, experiments are described in which nonuniform fields caused by a slot in a mumetal covering layer are used to guide magnetostatic surface waves through a turn of 160°.