Optical properties of Gd, Dy, and Tb†

Abstract

Optical constants in the spectral range 1.5–5.5 eV are presented for the heavy rare-earth metals Gd, Tb, and Dy. The samples are thin films prepared by vacuum evaporation at pressures below 10−9 torr, and are studied in situ using a precision ellipsometric technique. The optical spectra are broadly similar but differ slightly in their temperature dependence. The optical data complement recent magneto-optic spectra, and the significance of their difference is discussed in terms of existing electronic-structure models and the microscopic origin of the two spectra.