Features of the spectrum of exchange spin waves in planar Fe Ni/Dy/Fe Ni composites in the temperature range 4–300 K

The spin-wave resonance in a magnetic planar composite FeNi/Dy/FeNi on exchange spin waves with a wave vector along the normal to the surface in the temperature range of 4–290 K. It is established that in the region of 90–290 K, resonant absorption of high-frequency field energy is observed on individual layers of FeNi; the coupling of ferromagnetic layers is manifested in the appearance of optical satellites in acoustic spin-wave modes, the field coordinates of optical satellites indicate a positive interlayer coupling. A single spin-wave spectrum of a planar nanocomposite is observed in the 4–85 K region, which made it possible to measure the values of spin-wave stiffness for it. The features of the spin-wave spectrum are due to modifications of the magnetic structure of Dy and a change in the temperature of the dominant interaction of REM/PM on interfaces.