Magnetic and magneto-optical properties of assembly of nanodots obtained from solid-state dewetting of ultrathin cobalt layer

Abstract

An assembly of randomly organized cobalt nanoparticles were obtained by solid-state dewetting of a 3 nm-thick cobalt layer. Vibrating sample magnetometry and Brillouin light scattering techniques were used to investigate both their static and dynamic behaviors with respect to the initial native cobalt layer. The measurements obtained from the assembly of the obtained nanodots were analyzed by means of shape anisotropy contribution. The Brillouin spectra revealed an unusual reversed Stokes/anti-Stokes line height asymmetry comparing to that observed on the native layer. The effective optical properties of the nanodots, combined with the relation between mean field and inside-dot field allowed explaining the observed reversed height asymmetry. The assembly of nanodots behave as an effective magnetic and optical medium where these properties can be tuned by the elaboration process.