（Ｃｕ／ＳｉＯ２）積層膜を下地膜としたＦｅ，ＴｂＦｅ膜の磁気カー回転スペクトル

Abstract

The wavelength dependences of magneto-optical Kerr rotation angle (θK) and reflectivity (R) of thin Fe and TbFe films on the top of (Cu/SiO2) multilayer films have been measured in the wavelength region from 400 to 900 nm. The onset wavelength at which the reflectivity of (Cu/SiO2) multilayer films begins to increase shifts toward longer wavelength from the absorption edge of Cu, as increasing the thickness of SiO2 layer. θK of Fe and TbFe films on the top of these (Cu/SiO2) multilayer films is enhanced by more than a factor of 3 at the onset wavelength of these multilayer films, while reflectivities have minima. The figure of merit √RθK of these films reaches up to over twice as large as that of bulk metals at the θK peak wavelength. The calculated √RθK of Fe, TbFe/(Cu/SiO2) using optical constants of Fe, TbFe, Cu and SiO2 considering optical interference agrees with experimental results. With a proper choice of thickness of Cu and SiO2, the √RθK can be enhanced at any wavelength.