Configurational anisotropic spin waves in cross-shaped Ni80Fe20 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 (phi) of the in-plane bias magnetic field. As phi deviates from 0 degrees a single resonant mode splits into a numbers of modes, while the powers of the higher frequency modes increase as phi increases from 0 to 45 degrees. 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 phi = 0 degrees, while the effect increases with phi and becomes maximum at 45 degrees, making these elements interesting candidates as building blocks for magnonic devices. (C) 2013 AIP Publishing LLC.