Optical constants of polycrystalline Ni from 0.06 to 6.0 eV at 300 K

Abstract

Using spectroscopic ellipsometry from 0.06 to 6.0 eV at room temperature, the authors determined the optical constants (complex dielectric function, refractive index, and optical conductivity) of bulk cold-rolled polycrystalline Ni. To reduce the thickness of surface overlayers, the sample was heated in ultrahigh vacuum at 750 K for 6 h and then kept in vacuum during measurements. The authors analyze the optical constants using three alternative but mutually exclusive methods: they write the dielectric function as a multiband sum or product of Drude and Lorentz oscillators or with a Drude model with a frequency-dependent scattering rate and plasma frequency. Below 1 eV, they find significant contributions from both d-intraband transitions and free carriers.