Brillouin scattering investigation of nanomagnetic structures

Brillouin light scattering is employed to study the dynamical properties of arrays of vertical ferromagnetic nanowires and nanorings, which show great promise as high-density magnetic storage and sensor devices. Three closely related projects are reported: (1) observation of bulk magnon quantization in Ni nanowires: bulk spin wave quantization has been observed, and the magnon frequencies are found to decrease with increasing wire diameter. (2) investigation into the magnetic interaction between FeCo nanowires in closely-packed arrays: conclusive evidence of collective spin waves arising from the dipolar coupling which is manifested as a reduction in spin wave frequency with decreasing interwire spacing is found, and (3) study of the spin dynamics of large-aspect-ratio Ni nanorings: spin dynamics of high-aspect-ratio Ni nanorings is found to compare well with macroscopic theory. Micromagnetic simulations show that, for low applied magnetic fields, the nanorings undergo a transition from a b bamboob to b twisted bamboob magnetic state.

Author dc:creator

• WANG ZHIKUI

• Spin dynamics, nanostructure, Brillouin Light scattering, spin waves, nanomagnetism, ferromagnetism