Optical properties of bulk gadolinium in the range 0.5 to 3.1 eV

The measurement results of optical conductivity of bulk polycrystal gadolinium in the temperature range from 77 to 293 K and in the energy range from 0.5 to 3.1 eV are presented. The effect of the surface state on the spectrum character is discussed. It is found that the gadolinium spectrum consists of two bands with the energies of 1.1 and 1.6 eV at room temperature. The transition of the sample in the ferromagnetic state results in appearance of a new absorption band with approximately 0.66 eV energy. The possible causes of such a behaviour of the optical conductivity spectrum are considered