Brillouin light scattering study of an exchange coupled asymmetric trilayer of Fe/Cr

The magnetic response of a (211) oriented asymmetric Fe trilayer [Fe(100 إ)/Cr(9 إ)/Fe(20 إ)/Cr(20 إ)/Fe(20 إ)], in which the thickness of the Cr spacer layers was chosen to produce ferromagnetic coupling (F) between the two thinner Fe layers and antiferromagnetic coupling (AF) between the thicker Fe layer and the adjacent thin one, has been investigated using magnetization and Brillouin light scattering (BLS) measurements. The coupling coefficients, extracted by fitting the BLS and magnetization measurements with a theory treating the static and dynamic response on an equal footing, produced consistent values of the magnetic parameters. Our results confirm that the theoretical model used in interpreting both static and dynamic properties is valid even in systems in which F and AF coupling of the layers are simultaneously present. The theoretical model has also been extended to include the field dependence of the intensity of the Brillouin peaks. The calculated intensities are compared with the BLS spectra at different applied fields.