We study the permittivity (ε) of multilayer nanoisland systems [FeNi–Al₂O₃]_N with different layer thicknesses using spectral ellipsometry. A “metallic” behavior of the permittivity ($\mathrm{\text{Re}}(\epsilon )<0$) is found in structures with island FeNi layers, when there is a strong exchange interaction between the layers (dielectric layer thickness $d<2$ nm). When the exchange interaction in structures is strongly suppressed (Al₂O₃ layer's thickness $d>4$ nm), $\mathrm{\text{Re}}(\epsilon )>0$, which corresponds to the dielectric behavior of the permittivity. We conclude that the exchange interaction has a significant effect on the permittivity of structures. We also show that the $\mathrm{\text{Re}}(\epsilon )$ dependences on the FeNi layer thickness for multilayer and single-layer structures are very close when the dielectric layer thickness $d>4$ nm.

我们使用光谱椭偏法研究了具有不同层厚度的多层纳米岛系统 [FeNi-Al ₂ O ₃ ] _N的介电常数 ( ε ) 。介电常数的“金属”行为（$\mathrm{\text{关于}}(\epsilon )<0$) 存在于具有岛状 FeNi 层的结构中，当层之间存在强交换相互作用时（介电层厚度 $d<2$纳米）。当结构中的交换相互作用被强烈抑制时（Al ₂ O ₃层的厚度$d>4$ 纳米), $\mathrm{\text{关于}}(\epsilon )>0$，这对应于介电常数的介电行为。我们得出结论，交换相互作用对结构的介电常数有显着影响。我们还表明，$\mathrm{\text{关于}}(\epsilon )$ 多层和单层结构对 FeNi 层厚度的依赖性非常接近时，介电层厚度 $d>4$ 纳米。