Determination of Spin-Wave Boundary Conditions by dc Effects in Spin-Wave Resonance

A galvanomagnetic spin-wave experiment is described which, in conjunction with resonance absorption measurements in both uniform and nonuniform microwave fields, yields more information about the distribution of magnetization in spin-wave modes in ferromagnetic films than hitherto available, particularly for spin waves of low mode number. The method is applied to determine the spin-wave boundary conditions in 1200-Å Permalloy films, with the static field either parallel or perpendicular to the film plane. Homogeneous films show unpinned surfaces for the parallel orientation. In the perpendicular case, these films have a partly pinned film-glass interface, with anisotropies of a few tenths of 1 erg/${\mathrm{cm}}^2$, and an unpinned film-air surface. Parallel-orientation results for a film with a thin Ni over-coat indicate the excitation of a surface mode, which is also predicted by theory.