Electronic structure and half-metallicity in new Heusler alloys CoYO2 (Y=Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn)

Publication date: 15 September 2017
Source:Journal of Magnetism and Magnetic Materials, Volume 438
Author(s): S. Esteki, F. Ahmadian
First-principles calculations based on density functional theory (DFT) using the self-consistent full-potential linearized augmented plane wave (FPLAPW) method were applied to study the electronic structures and magnetic properties of new Heusler alloys CoYO2 (Y=Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn). The calculated formation energies of these compounds were negative, therefore, they can be synthesized experimentally. All compounds were stable in ferromagnetic AlCu2Mn-type structure. In AlCu2Mn-type structure, CoScO2, CoFeO2, and CoNiO2 compounds were HM ferromagnets, CoCuO2 was a nearly half-metal, CoZnO2 was a spin gapless semiconductor, and other compounds were conventional ferromagnets. In CuHg2Ti-type structure, CoTiO2 compound had a nearly HM characteristic, CoVO2 was a spin gapless semiconductor, and other compounds were conventional ferromagnets. The origin of the half-metallic band gap for CoScO2 alloy Heusler alloy was well understood. The total magnetic moments of the three HM compounds obeyed Slater-Pauling rules (Mtot=22-Ztot and Mtot=32-Ztot). CoScO2 had the widest region of half-metallicity between the three half-metals indicating its high robustness of half-metallicity with respect to the variation of lattice constants.



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