Light Wavelength Dependence of Magneto-Optical Properties in Ultrathin Co/Pt and Co/Pd Multilayered Films

Abstract

Magneto-optical (MO) properties of ultrathin Co/Pt and Co/Pd multilayered films containing thin Co layers were investigated as a function of light wavelength of 390–850 nm in comparison with that of amorphous TbFeCo system. The Kerr rotation angle θ_K of these multilayers with 150 Å thickness was nearly constant (0.38–0.42 deg for Co/Pt and 0.24–0.28 deg for Co/Pd) in the visible region, and the θ_K of the Co/Pt system tended to increase in the ultraviolet region. On the contrary, the MO properties of TbFeCo films diminished linearly with decreasing light wavelength. The figure of merit √Rθ_K of the Co/Pt films became 2.5 times larger than that of TbFeCo films at 400 nm. The ultrathin Co/Pt and Co/Pd multilayered films can be prominent material for higher-density MO recording using a shorter-wavelength laser.