Magneto-optical Kerr effect in perpendicularly magnetized Co/Pt films on two-dimensional colloidal crystals

Magneto-optical Kerr effect and optical reflectance are measured in the visible region for perpendicularly magnetized Co/Pt films on self-assembly array of two-dimensional closely packed polystyrene spheres. Peaks and valleys are observed in the magneto-optical Kerr and the optical reflectance spectra and their positions scale with the sphere diameter. In explanation of the above scenario, not only the Mie optical scattering of single nanocaps but also the surface plasmon resonance should be considered. This work will facilitate development of magnetoplasmonic nanosensors.