Optical constants of magnetron-sputtered magnesium films in the 25–1300 eV energy range

The transmittance of dc magnetron-sputtered Mg thin films was measured in the 25–1300 eV spectral range. Freestanding Mg films protected with Al layers were characterized ex situ. Transmittance measurements were used to obtain the extinction coefficient $k$ of Mg films. The obtained $k$ values along with the data available in the literature, and with interpolations and extrapolations for the rest of the spectrum, were used to obtain the real part of the index of refraction $n$ by the Kramers–Krönig analysis. Sum-rule tests indicated a good consistency of the data.