Spin-wave resonance in three-layer NiFe/Dy$_x$Co$_{1-x}$/NiFe films as a method for detecting structural inhomogeneities in amorphous Dy$_x$Co$_{1-x}$ Layers

The standing spin-wave spectrum was studied by spin-wave resonance in three-layer Ni$_{80}$Fe$_{20}$/Dy$_x$Co$_{1-x}$/Ni$_{80}$Fe$_{20}$ films with an amorphous interlayer of DyCo alloy in the region of compensation compositions. It is shown that the spin-wave resonance (SWR) spectrum in the geometry $k\parallel M$ is observed only for a planar system with a DyCo layer of precompensation composition. In the $k\perp M$ geometry, the SWR spectrum was observed for the DyCo systems with both pre-and postcompensation compositions. The exchange stiffness was analyzed as a function of the DyCo layer thickness to formulate a model of microheterophase structure for amorphous DyCo alloys in the compensation region, where the magnetic microstructure accounts for the dynamic and static magnetic characteristics of these materials.