Magneto-optical effect in GdN epitaxial thin film

Abstract

We report the cooperative phenomena of magneto-optical effect in AlN/GdN/AlN heterostructure grown by reactive rf magnetron sputtering technique performed under a base pressure less than 5×10-6 Pa. The ultra-high vacuum conditions during growth of GdN enable to curtail the oxophilicity character. The temperature dependent optical absorbance measurements have been carried out to evaluate the direct optical band gaps at the X point through the Tauc plots for the heterostructure. We observed for the first time that the optical absorbance studies demonstrate an exceptional splitting in valance and conduction bands in GdN below the critical temperature. The splitting energy is slightly increased with increase of temperature range of 30-55 K and the difference is merely ΔE=28 meV. Furthermore, the splitting energy drastically increases from 30 K to 3 K and the difference is ΔE=102 meV. This startling increase convincing that there is rapid increase of magnetic moments caused by long range correlation of spins.