Electronic structure, optical and magnetic properties of Co$_{2}$FeGe Heusler alloy films

TL;DR

This study combines experimental and theoretical approaches to analyze the electronic, optical, and magnetic properties of Co$_{2}$FeGe Heusler alloy films, revealing near-perfect spin polarization and validating the material's potential for spintronic applications.

Contribution

It provides new experimental data and first-principles calculations demonstrating the half-metallic nature and optical properties of Co$_{2}$FeGe films.

Findings

Saturation magnetization close to Slater-Pauling prediction

Strong optical absorption in 1-4 eV range

Agreement between measured and calculated electronic spectra

Abstract

Optical properties of ferromagnetic half-metallic full-Heusler Co$_{2}$FeGe alloy are investigated experimentally and theoretically. Co$_{2}$FeGe thin films were obtained by DC magnetron sputtering and show the saturation magnetization at $T$=10 K of $m\approx$5.6 $\mu_{B}$/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 (GGA) and GGA+U approximations. 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.