Collective Behavior Induced Highly Sensitive Magneto-Optic Effect in 2D Inorganic Liquid Crystals

TL;DR

This paper demonstrates that introducing collective behavior in 2D magnetic liquid crystals significantly enhances their magneto-optic effects, enabling highly sensitive magneto-coloration and potential for advanced sensing devices.

Contribution

It reveals a novel method to amplify magneto-optic effects in 2D materials by controlling collective behavior through ionic strength, achieving record-high Cotton-Mouton coefficients.

Findings

Record-high Cotton-Mouton coefficient of 2700 T-2m-1.

Linear dependence of magneto-coloration on ion concentration.

Potential for fabricating giant magneto-birefringent sensors.

Abstract

Collective behavior widely exists in nature, ranging from the macroscopic cloud of swallows to the microscopic cloud of colloidal particles. The behavior of an individual inside the collective is distinctive from its behavior alone, as it follows its neighbors. The introduction of such collective behavior in two-dimensional (2D) materials may offer new possibilities to achieve desired but unattained properties. Here, we report a highly sensitive magneto-optic effect and transmissive magneto-coloration via introducing collective behavior into magnetic 2D material dispersions. The increase of ionic strength in the dispersion enhances the collective behavior of colloidal particles, giving rise to a magneto-optic Cotton-Mouton coefficient up to 2700 T-2m-1 which is the highest value obtained so far, being three orders of magnitude larger than other known transparent media. We also reveal linearly dependence of magneto-coloration on the concentration and hydration radius of ions. Such linear dependence and the extremely large Cotton-Mouton coefficient cooperatively allow fabrication of giant magneto-birefringent devices for color-centered visual sensing.