Electron doping and correlation effects on crystal, electronic and magnetic structures of A$_2$NRuO$_6$ (A2 = Ba$_2$, BaLa; N = V, Cr, Fe)

Abstract

Density functional methods have been used to study the crystal, electronic and magnetic structures of new ordered double perovskites A2NRuO6 (A2 = Ba2, BaLa; N = V, Cr, Fe). In the doped compounds, the A-site was replaced by 1:1 of Ba and La cations, BaLaNRuO6. All compounds of A2NRuO6 crystallize in cubic symmetry with space group Fm-3m and tilt system a0a0a0. The electronic and magnetic calculations were performed by the full-potential linear muffin-tin orbital method using both the generalized gradient approximation and GGA plus on-site electron correlation effect GGA+U. In GGA, Ba2NRuO6 shows half-metallic, semiconducting and metallic behavior for N = V, Cr, Fe, respectively, completely change to half-metallic when A2 = BaLa. While, GGA+U method yields clearly half-metallic in all compounds, except for Ba2FeRuO6, shows an insulating behavior. Also, the results of magnetic structures calculations reveal that the A2NRuO6 compounds have ferrimagnetic nature if N = V and Cr, switch to ferromagnetic when N = Fe. The V3+, Cr3+, Fe3+ and Ru5+ ions are in high spin magnetic moments states due to the antiferromagnetic coupling.