Optical investigation of γ-Fe2O3 nanoparticle-doped silica gel matrix for birefringent components

We present an optical study of silica gel matrix doped with maghemite γ-Fe₂O₃ nanoparticles originating from a ferrofluid. This work is a preliminary study for building adjusted birefringent components suitable for ellipsometry. Silica gel matrix is obtained as sol-gel synthesis. Results show that pure and doped samples solidified out of a magnetic field are quasi-isotropic, whereas samples solidified in the presence of a magnetic field exhibit a very large permanent linear birefringence comparable to that produced by the ferrofluid under the same magnetic field