The Effects of Surface Layers on Spin‐Wave Spectra in YIG Films

Abstract

Abstract Experimental spin‐wave spectra for thin magnetic (YIG) films have been matched by computations in which the surface boundary conditions were provided by thin surface layers with magnetic properties different from the bulk. In the case of annealed films, a diffusion layer between the film and its non‐magnetic substrate (GGG) is assumed to result from the thermal annealing. Thislayer is shown to produce a surface anisotropy field similar to the tensorial field postulated by Yu, Turk, and Wigen. This model accurately predicts the experimental spin‐wave spectra for all angular orientations of the applied field and qualitatively predicts the temperature dependence of the critical angle, the angle at which only the uniform mode is excited. Expressions for the resonance field and the critical angle are derived. The properties of the surface layers are discussed and the model is compared with experimental data from annealed and unannealed YIG films.