Variational formulation of magnetostatic wave dispersion relations

A new variational formulation is described for the calculation of magnetostatic wave dispersion relations. Formulas are presented which should enable estimates of the effects of various inhomogeneities to be readily obtained, given a reasonable estimate of the magnetostatic potential Ψ. The results of numerical calculations are presented which demonstrate the relative insensitivity of the formulas to small errors in the trial function Ψ when applied to the well-known magnetostatic modes of an isolated ferrite slab.