Damped surface modes in thick yttrium iron garnet films

Abstract
Damped surface modes in thick YIG epilayers which appear at low fields close to the Damon‐Eshbach limit in microwave spectra with the dc magnetic field parallel to the surface have been investigated. The results are explained in terms of the De Wames–Wolfram model, when a surface anisotropy energy due to the effect of a diffusion layer on the spins at the substrate/film interface is taken into account. In accordance with the experimental results, the above theoretical assumption leads to a low value of the parallel wave vector ky for which those modes can be excited (≲103 cm−1).