Magnetic properties and half metallic behavior of the Full-Heusler Co2FeGe alloy: DFT and Monte Carlo studies

Highlights: • The physical properties of the Heusler compound Co₂FeGe are studied. • The Monte Carlo study is applied. • The First principle calculations are also applied to this system. • The Curie temperature is determined and discussed. The study of structural, electronic and magnetic alloy properties of the full-Heusler Co₂FeGe has been undertaken using the first principle method based on the density functional theory (DFT). In this work, we have predicted and underlined the mechanism of the half-metallic behavior of the full-Heusler Co₂FeGe alloys by using the Monte Carlo simulations. We have used the full potential linear augmented plane wave (FPLAPW) method as implemented in the Wien2K code to forecast the electronic and magnetic properties of the studied system. We have used the generalized gradient approximation GGA for the treatment of exchange energy and correlation. We have also taken into account the strong correlations orbital of Co and Fe atoms by applying the GGA+U approximation founded on DFT+U. The GGA+U gives a good result showing that compound Co₂FeGe is a half-metallic ferromagnetic (HMF) through a large gap of 1.20eV. The value of the magnetic moment is used as input to calculate the magnetic parameter of this alloy when using the Monte Carlo simulations. By the help of the proposed model the temperature dependency of the magnetization, the susceptibility and the specific heat, is studied. The phase transition is of second order type at the critical temperature point. This temperature is in good agreement with the available experimental data.