Ab initio predictions of stability, half-metallicity and magnetism in Co2NbAl and Co2ZrAl full-Heusler alloys

Abstract

This paper reports ab initio computed results of stability, phonon, electronic, magnetic, and surface properties of Co2NbAl and Co2ZrAl full-Heusler alloys. These alloys are stable, which is confirmed by formation energy, cohesive energy, and phonon spectra. The total magnetic moments of these alloys follow the Slater-Pauling (SP) rule (Mt = Zt-24). The Nb (111) and Al (111)-terminations of Co2NbAl show half-metallic characteristic, while other terminations are metallic due to the majority density of states (DOS) and the minority DOS at the Fermi level. CoCrNbAl and CoCrZrAl show half-metallicity while CoMnZrAl and CoFeNbAl exhibit metallic nature after the substitution of Cr, Mn, and Fe atom in Co2NbAl and Co2ZrAl, respectively. The electronic structures exhibit the band gaps of 0.39 eV, 0.24 eV, and 1.19 eV for CoFeNbAl, CoCrNbAl, and CoCrZrAl, respectively. The calculated values of the magnetic moments are in good agreement with experimental data. The results confirm that Co2NbAl, Co2ZrAl, CoFeNbAl, CoCrNbAl, and CoCrZrAl can be promising alloys for spintronic devices.