Three dimensional magneto-photonic crystals were realized by a low temperature sol-gel method. Self-assembled polystyrene direct opals were impregnated by CoFe2O4 nanoparticles doped silica sol-gel solution. The silica composite inverse opal structure was then created by dissolving original polystyrene photonic crystal structure using ethyl acetate. Ellipsometric and magneto-optical measurements carried-out on silicadoped monolayers evidence that the amount of nanoparticles in the matrix can reach 39%. Scanning electron microscope images of inverse opals confirm that a 3D arrangement is obtained. Transmittance measurements show a combination of photonic band gaps with the absorption of the nanoparticles. The central positions of these band gaps are in accordance with the diameter of the initial spheres through the Bragg law. Finally, nonreciprocal magneto-optical effect is demonstrated in the inverse opals through a Faraday effect hysteresis loop. It proves the ability of the method to produce magneto-photonic crystal materials.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials