Configurational anisotropic spin waves in cross-shaped Ni ₈₀Fe₂₀ nanoelements

Optically induced spin waves in Ni₈₀Fe₂₀ (permalloy) cross-shaped nanoelements are studied by time-resolved magneto-optical Kerr effect microscope. A strong anisotropy in the spin wave modes are observed with the orientation angle () of the in-plane bias magnetic field. As deviates from 0° a single resonant mode splits into a numbers of modes, while the powers of the higher frequency modes increase as increases from 0 to 45°. The lowest frequency mode shows a four-fold configurational anisotropy. The mode of a single cross remains unaffected by the magnetostatic interaction of the neighbouring elements for 0°, while the effect increases with and becomes maximum at 45°, making these elements interesting candidates as building blocks for magnonic devices.