Optical and magneto-optical constants of ${\mathrm{MnPt}}_3$s

Optically thick films of ${\mathrm{MnPt}}_3$ were deposited on quartz using dc magnetron sputtering. The films were covered with an ${\mathrm{SiO}}_{\mathrm{x}}$ protective overcoat and annealed in vacuum at 850 °C for 1 h to form the crystalline ${\mathrm{L}1\mathrm{}}_2$ (${\mathrm{Cu}}_3$ Au) cubic structure. These films have a high degree of long-range order and are highly textured with the (111) axis along the film normal. Variable angle spectroscopic ellipsometry measurements were taken over the spectral range of 1.2–4.2 eV to determine the optical constants of both ${\mathrm{MnPt}}_3$ and the ${\mathrm{SiO}}_{\mathrm{x}}$ overcoat. Spectroscopic magneto-optic Kerr rotation and ellipticity measurements at near normal incidence over the spectral range of 1.4–3.6 eV were used to determine the off-diagonal dielectric tensor elements for ${\mathrm{MnPt}}_3$ . First-principles electronic-structure calculations were carried out for the ordered ${\mathrm{MnPt}}_3$ structure and from these the dielectric tensor elements of ${\mathrm{MnPt}}_3$ were calculated. The experimental and theoretical values of the diagonal components of the dielectric tensor components are in good agreement. The agreement for the off-diagonal components of the dielectric tensor is only fair.