Enhanced Transmission and Giant Faraday Effect in Magnetic Metal-Dielectric Photonic Structures

TL;DR

This paper demonstrates that a layered structure of cobalt nano-layers and dielectrics can achieve high transmission and significant Faraday rotation at microwave frequencies, overcoming the reflectivity of metallic films.

Contribution

It introduces a novel multilayer design enabling large Faraday rotation and high transmission in ferromagnetic metal-dielectric structures, which was previously difficult due to metallic reflectivity.

Findings

Achieves 45-degree Faraday rotation with nanometer-thick cobalt layers.

Demonstrates high transmission in layered ferromagnetic structures.

Shows potential for microwave device applications.

Abstract

Due to their large electric conductivity, stand-alone metallic films are highly reflective at microwave frequencies. For this reason, it is nearly impossible to observe Faraday rotation in ferromagnetic metal layers, even in films just tens of nanometers thick. Here, we show using numerical simulations that a stack of cobalt nano-layers interlaced between dielectric layers can become highly transmissive and display a large Faraday rotation in a finite frequency band. A 45-degree Faraday rotation can be achieved with metallic ferromagnetic layers as thin as tens of nanometers.