Shape-manipulated spin-wave eigenmodes of magnetic nanoelements

The magnetization dynamics of nanoelements with tapered ends have been studied by micromagnetic simulations. Several spin-wave modes and their evolutions with the sharpness of the element ends are characterized. The edge mode localized in the two ends of the element can be effectively tuned by the element shape. Its frequency increases rapidly with the tapered parameter h and its localized area gradually expands toward the element center, and it finally merges into the fundamental mode at a critical tapered parameter h₀. For nanoelements with h > h₀, the edge mode is completely suppressed. The standing spin-wave modes mainly in the internal area of the element are less affected by the element shape. The shifts of their frequencies are small and they display different tendencies. The evolution of the spin-wave modes with the element shape is explained by considering the change of the internal field.