Experimental dependence of the SSW linewidth with wavenumber in permalloy films

Films of Permalloy for which standing spin-wave (SSW) linewidths do not increase with wavenumber have been experimentally obtained. It is shown that the broadening of the linewidth with wavenumber in the case of oblique incidence evaporation is quantitatively explained by a calculation of ΔHntaking into account the gradient of film thickness determined by the evaporation law. It is concluded that the interactions between different regions of the film do not appreciably influence the SSW linewidth, and that the effect of the thickness dropoff which appears at the edge of the films is negligible. In addition, it is shown that films of relatively large dimensions with a constant and small linewidth can be obtained by a careful arrangement of the evaporation system.