Electronic structure, optical and magnetic properties of Co₂FeGe Heusler alloy films

Optical properties of ferromagnetic half-metallic full-Heusler $Co2FeGe$ alloy are investigated experimentally and theoretically. $Co2FeGe$ thin films were obtained by DC magnetron sputtering and show the saturation magnetization at T = 10 K of $m≈5.6μB/f.u.$⁠, close to the value predicted by the Slater-Pauling rule. First-principles calculations of the electronic structure and the dielectric tensor are performed using the full-potential linearized-augmented-plane-wave method in the generalized gradient approximation (GGA) and GGA + U approximation. The measured interband optical conductivity spectrum for the alloy exhibits a strong absorption band in the 1–4 eV energy range with pronounced fine structure, which agrees well with the calculated half-metallic spectrum of the system, suggesting a near perfect spin-polarization in the material.