Tuning the electronic and magnetic properties of Heusler alloys: A theoretical and experimental investigation*

Half metallic Heusler alloys have attracted recent attention because they are suitable materials for information storage and spintronics applications. This work presents a detailed experimental and theoretical study on a series of Fe_3-xV_xGe, Fe_3-xCr_xGe, Co₂Fe_1-xV_xGe, and Co_2-xV_xFeGe (0 ≤ x ≤ 1) Heusler alloys. To study these alloys, we used the cluster expansion formalism, which uses density functional theory (DFT) calculated energies as a training set, and ultimately gives us the energetics of an alloyed system as a function of concentration. We employed DFT calculations at the GGA and GGA+U level to calculate the energetic stability and the structural, electronic, mechanical and magnetic properties of each alloyed system at specific alloying ratios. Experimental measurements for these materials such as stability, lattice parameter and magnetic moment are in agreement with our calculations. Our results also confirm the half metallicity of certain alloyed materials. The findings of this study not only confirm previous experimental measurements, but can aid future experimentalists and manufacturers in the synthesis of other Heusler alloys with specific desired properties.