Theoretical Study of the Localized Spin States at the Surface of a Ferromagnetic Diatomic Alloys

From the spin dynamics matrix describing the precession of ferromagnetically coupled spins, in a semiinfinite fcc diatomic alloy, we easily access to the localized magnons spectra of the surface of the material. The modeling is carried out by a calculation based on a Heisenberg Hamiltonian with the nearest neighbor interactions and in the presence of the anisotropy term. The localized magnon spectra are calculated and analyzed for different probabilities of the values of the integral exchange and the anisotropy field at the surface of the perfect diatomic alloy waveguide. The simulated cases investigate the magnon modes response to variations in surface parameters (exchange integrals, anisotropy intensity, as well as to the direction of propagation of the exciting spin wave). The numerical results yield an understanding the interference effects between the continuum and the localized spin states on the atomic layers which constitute the surface domain.