Magneto-optical AlN/Fe/AlN structures optimized for operation in the violet spectral region

The magneto-optical (MO) polar Kerr response of AlN/Fe/AlN/Cu/Si structures was optimized for a wavelength of 410 nm. Prior to the growth of the structures, the optimal thicknesses of the individual layers were determined by modelling to find the maximum MO figure of merit. Then the structures with different thicknesses of AlN layers were grown by sputtering. The optical properties of the AlN layers, grown by reactive sputtering, were characterized by ellipsometry. The MO polar Kerr spectroscopy was employed to measure the performance of the structures in the field of 3 kOe. The MO signal was scaled for saturation (factor 7) and saturation azimuth rotation greater than 20° was observed. The agreement between calculation and experimental data was remarkable, verifying the correct set of optical and MO parameters used in the model. These results provide a guide for the design of a MO sensor with optimal performance at a desired wavelength.