Guiding magnetostatic surface waves with nonuniform in-plane fields

The observation of magnetostatic surface waves (MSSW's) was recently reported in a rectangular YIG film placed between strips of mu-metal and in the plane of the strips. However, the interpretation of this experiment was complicated by the fact that the field was nonuniform not only in the transverse direction but along the direction of propagation as well. This latter nonuniformity resulted because the microstrip antenna structure did not allow the strips to extend along the entire path of propagation. Reported here are experiments using a rectangular slab and a different antenna structure which minimizes this difficulty. These experiments suggest that nonuniform in-plane fields can be used to alter the dispersion characteristics of the waves. In addition, new experiments are described in which nonuniform fields caused by a slot in a mu-metal covering layer are used to guide MSSW's through a turn of 160 deg.