The optical and dielectric properties of plasmonic of Fe₂O₃/Au and Fe₃O₄/Au core/shell nanoparticles were studied using Finite Element computational approach. The optical response of these nanostructures was investigated through the computation of the real and the imaginary parts of the effective dielectric permittivity and the absorption cross-section in the visible-near infrared spectral range. Our findings are as follows. Firstly, we have compared our obtained numerical results with those predicted by Maxwell–Garnett effective medium theory. Secondly, the obtained results reveal that the localized surface plasmons resonance (LSPR) peak shifts to near infrared for a Fe₂O₃/Au-nanoparticle are similar to that of a Fe₃O₄/Au-nanoparticle having the same geometric parameters. Thirdly, the optical characteristics of the plasmonic nanoparticles were also studied. Finally, we hope that the developed numerical method can be extended to investigate the electromagnetic coupling within or between particles and its effect on the plasmonic behaviors. This makes the core/shell composite nanoparticles extremely interesting for magnetic, optical and biomedical applications.

使用有限元计算方法研究了 Fe ₂ O ₃ /Au 和 Fe ₃ O ₄ /Au 核/壳纳米粒子的等离子体的光学和介电特性。通过计算有效介电常数的实部和虚部以及可见-近红外光谱范围内的吸收截面，研究了这些纳米结构的光学响应。我们的发现如下。首先，我们将我们获得的数值结果与 Maxwell-Garnett 有效介质理论预测的结果进行了比较。其次，所得结果表明，对于 Fe ₂ O ₃，局域表面等离子体共振 (LSPR) 峰移至近红外。/Au-纳米颗粒类似于具有相同几何参数的Fe ₃ O ₄ /Au-纳米颗粒。第三，还研究了等离子体纳米粒子的光学特性。最后，我们希望开发的数值方法可以扩展到研究粒子内部或之间的电磁耦合及其对等离子体行为的影响。这使得核/壳复合纳米粒子在磁性、光学和生物医学应用中非常有趣。