Band structure of a 2D photonic crystal based on ferrofluids of Co0.8Zn0.2Fe2O4 nanoparticles under perpendicular applied magnetic fields

21st Latin American Symposium on Solid State Physics

López, J.^1 ; González, Luz E^1 ; Quiñonez, M.F.^1 ; Porras-Montenegro, N.^1 ; Zambrano, G.^1 ; Gómez, M.E.^1

Departamento de Física, Universidad Del Valle, A.A. 25360 Cali, Colombia^1

关键词: 2-D photonic crystals;    Applied magnetic fields;    Effective permittivity;    Effective refractive index;    External magnetic field;    Maxwell-garnett theory;    Photonic band structures;    Plane wave expansion method;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/480/1/012033/pdf
DOI  :  10.1088/1742-6596/480/1/012033

来源: IOP

【 摘 要 】

Using a ferrofluid of cobalt-zinc ferrite nanoparticles (Co0.8Zn0.2Fe2O4) coated with oleic acid and suspended in ethanol, we have fabricated a 2D photonic crystal (PC) by the application of an external magnetic field perpendicular to the plane of the ferrofluid. The 2D PC is made by rods of nanoparticles organized in a hexagonal structure. By means of the plane-wave expansion method, we study its photonic band structure (PBS) which depends on the effective permittivity and on the area ratio of the liquid phase. Additionaly, taking into account the Maxwell-Garnett theory we calculated the effective permittivity of the rods. We have found that the effective refractive index of the ferrofluid increases with its magnetization. Using these results we calculate the band structure of the photonic crystal at different applied magnetic fields, finding that the increase of the applied magnetic field shifts the band structure to lower frequencies with the appearance of more band gaps.