| Summary: | 碩士 === 國立臺灣大學 === 應用物理所 === 99 === FeCo/NiO half-shell arrays were fabricated based on the periodic monolayer polystyrene spheres. The two-dimensional magnetic periodic arrays form well-defined photonic crystals with pronounced stop bands. Quite interestingly, it is found that the stop bands can be tuned by an external magnetic field. In our experiment, the colloid of 900 nm-diameter periodic polystyrene spheres (PSS) was dropped on a clean glass substrate at room temperature, and they would self-assemble to form a two dimensional monolayer PC. The PSS PCs were deposited with 10 nm Ni film by evaporation. The PS and the Ni film were annealed in Ar gas at 450。C, a temperature higher than the boiling point of PS for three hours. The PSS were evaporated, and the half-shell array of NiO was formed. Finally, the half-shell NiO array was deposited with 30 nm FeCo film by a high vacuum magnetron sputtering system, and the weight percentages of Fe and Co were 25% and 75%, respectively. We have successfully demonstrated that the PC stop bands based on FeCo/NiO half-shell arrays can be manipulated by an external magnetic field. The underlying physics is attributed to the controllable dielectric constant of magnetic FeCo film when an external magnetic field is applied. The result shown here may open up a possibility for the creation of new magneto-optical devices based on photonic crystals.
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