Brillouin light scattering in ferromagnetic single layers: hysteresis loop and backward geometry

We present a Brillouin light scattering study of a thick ferromagnetic single layer Ni80Fe20 (44 nm) film, using two different geometrical setup: (i) the so-called Damon-Eschbach (DE) geometry where the in-plane wave vector Q// of the studied spin wave is perpendicular to the external magnetic field H and (ii) the backward geometry (BW) where it is parallel to H (Q// and H lie in the film plane). An in-plane uniaxial anisotropy that do not exceed 100 Oe is evidenced through the analysis of the variations of DE mode frequency and of the Stokes/anti-Stokes dissymmetry versus H. The experimental magnetic Brillouin spectra showing the presence of dipolar and exchange standing spin waves are well reproduced for both geometries by our calculations of the scattered intensity using the following magnetic parameters: 4πM = 9400 G; g = 2.13; A = 0.93 10–6 erg.cm–1 for different values of the magnetic field H and of the in-plane wave vector amplitude Q//. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)