Ellipsometry, reflectance photometry and Kerr polarimetry have been used to determine the optical and magneto-optical properties of bulk single-crystal platelets and thin films of Co-Ti-doped barium hexaferrite. The single crystals were grown by a slow-cooling flux method and the thin films were produced by pulsed laser ablation deposition onto single-crystal Al2O3 substrates at 840°C. The complex refractive index (n) and magneto-optic Voigt parameter (Q) were determined over the spectral range 350–850 nm and the reliability of the data tested by comparison with photometric measurements of reflectance. Although the optical constants of the thin films could not readily be obtained over the entire spectral range by ellipsometry, their magneto-optical performance in terms of the Kerr rotation and ellipticity compared well with predictions based on the fundamental data for the bulk material.
Atkinson, R., Papakonstantinou, P., Salter, IW., & Gerber, R. (1994). Optical and magneto-optical properties of Co-Ti-substituted barium hexaferrite single crystals and thin films produced by laser ablation deposition. Journal of Magnetism and Magnetic Materials, 128, 222-231. https://doi.org/10.1016/0304-8853(94)90420-0