Showing papers by "Daniel D. Stancil published in 1980"

Magnetostatic surface modes in a thin film with nonuniform in-plane fields

Abstract: The experimental observation of magnetostatic surface waves (MSSW's) in a rectangular YIG film placed between strips of permalloy and in the plane of the strips is reported. In such a configuration, the DC magnetic field between the permalloy strips is primarily in-plane with a minimum halfway between and increasing toward each strip. In the presence of such a gradient, a series of discrete modes appears near the low frequency end of the normally continuous MSSW band. The frequencies of these modes lie below the bottom of the conventional MSSW band as calculated from the field at the center of the sample where the field is minimum. However, reversing the bias field reduces the coupling to these modes indicating a nonreciprocal surface localization. Estimates of the group velocities of these modes based on the slope of phase vs. frequency data indicate that the discrete modes travel several times faster than conventional MSSW's.

Magnetostatic waves in nonuniform bias fields including exchange effects

Abstract: The method of expansion in normal spin wave modes has been extended to the case of a two-dimensional nonuniformly magnetized ferrite with the effects of exchange included. The direction of the nonuniform bias field is normal to the plane of the ferrite. Using this method, a number of solutions (both exact and approximate) to the linearized magnetostatic equations have been obtained. Correspondence is pointed out between the new solutions, the spin wave theory of Eshbach, and the magnetostatic theory of Morgenthaler. These solutions further elucidate the role of exchange in magnetostatic wave propagation in nonuniform fields.