Surface modes in magnetic thin films and in spin wave resonance

Of late, the number of papers on magnetic surface states has greatly increased since the experimental detection of these states has been proven to open up a highly promising source of abundant data on the magnetic properties of materials. Spin wave resonance (SWR)-an effect observed in thin ferromagnetic films-is well adapted for such detection. In this paper, we are concerned with the theoretical conditions for surface mode detection in SWR. Since SWR depends essentially on the conditions existing on the surfaces of a film, we begin with a closer analysis of the concept of surface spin pinning. Next, resorting to the Surface Inhomogeneity Model (thin film, totally homogeneous within, but presenting arbitrary asymmetric conditions on its surfaces), we solve the problem of the existence of surface modes as a function of the pinning conditions, and discuss the essential features of these modes. Finally, we propose a criterion for identifying surface peaks in SWR spectra.