Optical and magnetic properties of elliptical hematite (α-Fe₂O₃) nanoparticles coated with uniform continuous layers of silica of different thickness

Elliptical-type α-Fe2O3 nanoparticles with/without silica shell have been prepared. The core particles were coated with uniform continuous layers of silica of two different thicknesses by hydrolysis of TEOS. The obtained HCP structure elliptical α-Fe2O3 nanoparticles with ∼ 240 nm length and 100 nm width is polycrystalline in nature. The thicknesses of SiO2 shell coated on α-Fe2O3 are about 55 and 30 nm, respectively. The optical and magnetic properties of these nanoparticles have been investigated.