Spin-wave resonance in one-dimensional magnonic crystals by an example of multilayer Co–P films

Layered magnetic films of Co–P alloy, which are sets of laminates with certain atomic and chemical structures, have been investigated by spin-wave resonance. Coatings of two types were synthesized: a magnonic crystal (amorphous Co(P)/fcc Co(P))$_N$ and gradient Co(P) films. They exhibit two different modifications of the spin-wave resonance (SWR) spectrum. In the first case, the SWR spectrum is described as $H_{n}(n)\sim n^2$ with a modification caused by the formation of the first stop band of the magnonic crystal. In the second case, the dependence of resonance fields Hn of the spin-wave modes on mode number $n$ has the form of $H_{n}(n)\sim n^{2/3}$. Thermal annealing leads to crystallization (amorphous alloy $\to$ fcc) and causes transformation of the layered films to the films of single-phase Co–P alloys, which is accompanied by a change in the shapes of the SWR spectra and occurrence of a “exchange kink” spectral modification.