We used Brillouin light scattering to show that shape distortions in Ni80Fe20 nanoelements can have a dramatic effect on the measured linewidth of certain modes. By intentionally introducing an amount of egg-like shape distortion to an ideal elliptical structure, we show that the modes whose amplitude are concentrated at the edges become non-degenerate and separate in frequency. In contrast, modes whose amplitude is concentrated in the interior of the nanostructures are significantly less affected by the distortion. This effect of mode splitting may explain the large inhomogeneous linewidth broadening observed in end modes in large ensembles of nanomagnets due to small fluctuations in shape from nanostructure to nanostructure.
Citation: Journal of Applied Physics
Pub Type: Journals
nanomagnetism, magnetodynamics, spin-dynamics, nanostructures, Brillouin light scattering