Ellipsometric and magneto-optic properties of sputtered dysprosium-iron multilayers

Ellipsometric and magneto-optical properties of Dy (3.5 Å thick) and Fe (2.5-12.5 Å thick) multilayers were investigated over the spectral range from 3000 to 8000 Å in magnetic fields to 0.21 T. In this range of layer thickness the magnetic anisotropy is vertical. Kerr rotations, were found to be weakly spectrally dependent, and as large as 0.06°. The magnetically driven change of ellipticity of reflected light was as large as 0.13, depending on sample and wavelength. Ellipsometric analysis of layer thickness was performed assuming a multilayer geometry. In addition, the optical constants were determined assuming the multilayer was a homogeneous layer with "effective" properties.