Tunable Birefringence in Silica Mediated Magnetic Fluid

TL;DR

This study explores how silica nanoparticles influence the magnetic and optical properties, especially birefringence, of lauric acid stabilized magnetic fluids, revealing tunable optical behavior linked to silica concentration and magnetization.

Contribution

First report demonstrating direct silica-magnetite interaction in magnetic fluids and its impact on tunable birefringence and magnetic properties.

Findings

Silica addition suppresses birefringence in FN30 but enhances it in F30.

Magnetic field induces different chain structures depending on silica content.

Particle size increases with silica addition, affecting magnetic and optical properties.

Abstract

The present study reports magnetic and optical properties of silica mediated lauric acid stabilized magnetic fluids. The tunable birefringence ({\Delta}n) and other properties are investigated as a function of (i) concentrations of silica suspension, and (ii) saturation magnetization (MS) 0.5099 kA/m (FN30) and 1.2855 kA/m (F30) of magnetite magnetic fluid (MF). The study reveals that {\Delta}n suppresses on addition of silica in FN30, whereas enhances (up to critical concentrations of silica) in F30. The magnetic field induced chain observed in the FN30 based fluids are long, thick and scattered, while short, thin and dense chains emerges in F30 based fluid. The magnetic field induced assembly and the magnetic parameters correlates with the results of {\Delta}n. The particle size analysis indicates increment of particle size on addition of silica nanoparticles. The thermogravimetry analysis confirms the direct interaction of silica nanoparticles and the lauric acid coated magnetite particles. This is the first report of direct interaction of silica - magnetite magnetic fluids, and its subsequent effect on tunable birefringence and other properties.