Biasing the ferronematic - a new way to detect weak magnetic field

TL;DR

This paper explores how applying a weak dc magnetic bias to ferronematics in their isotropic phase significantly enhances their ac magnetic susceptibility, with potential applications in low-field sensing and information storage.

Contribution

It introduces a novel method of biasing ferronematics to control their magnetic response, revealing irreversible changes across phase transitions.

Findings

Weak dc bias increases ac susceptibility in ferronematics

Phase transition resets the magnetic enhancement

Potential for low magnetic field sensor applications

Abstract

Magnetic properties of a ferronematic, i.e., nematic liquid crystal doped with magnetic nanoparticles in low volume concentration are studied, with the focus on the ac magnetic susceptibility. A weak dc bias magnetic field (units of Oe) applied to the ferronematic in its isotropic phase increases the ac magnetic susceptibility considerably. Passage of the isotropic-to-nematic phase transition resets this enhancement irreversibly (unless the dc bias field is applied again in the isotropic phase). These experimental findings pave a way to application possibilities, such as low magnetic field sensors, or basic logical elements for information storage.