Using Se and Ga concentration to adjust the structural, magnetic, electronic and mechanical characteristics of Co2MnGe alloy: A Monte Carlo and DFT approach

Co₂MnGe_1-xY_x (Y= Ga and Se with x = 0, 0.25, 0.50 and 0.75) compounds structural, electronic, magnetic, and optical characteristics are examined using Monte Carlo simulation and first-principles calculations using the generalized gradient approximation. These compounds computed structural characteristics indicate that when Se and Ga substitution x increase, the lattice constants marginally increase as well. At their optimal lattice constants, the band structure computations predict that these compounds are half-metallic ferrimagnets for Se substitution and half-metallic ferromagnets for Ga substitution. The atomic and total magnetic moments remain unchanged when the Ge atom is partially replaced by Se and Ga. The calculated magnetic moment values of our compounds accord well with both theoretical and experimental findings. Large spin polarization and half-metallicity are desired for applications in spintronics. At H = 4 T, the specific heat and magnetic entropy changes reach their maximums of 75.30 J mol⁻¹ K⁻¹ and 0.72 J kg⁻¹ K⁻¹.