Magnetoplasmonic properties of Ag-Co composite nanohole arrays

The magnetoplasmonic properties of Ag-Co composite nanohole arrays are investigated. It is observed that both plasmonic and magnetic properties of the Ag-Co composite nanohole arrays strongly depend on the composition ratio of Ag and Co. The enhanced optical transmission due to plasmonic resonance decreases with the increase of the Co component while the Faraday rotation effect increases monotonically. The magnetization dynamics of a composite thin film is also modified by the composition as well as the introduction of hole arrays. The Ag-Co composite nanohole arrays with the Co content of 30% show high plasmonic–magneto-optics performances compared with that of Ti-Co composite nanohole array, and annealing of the Ag-Co composites in vacuum can further improve this property. All experimental results are confirmed by the finite-difference time-domain calculations. Such a magnetoplasmonic composite material can act as a class of materials for magnetoplasmonic devices or metamaterial applications.