Electron doping and correlation effects on crystal, electronic and magnetic structures of A2NRuO6 (A2 = Ba2, BaLa; N = V, Cr, Fe)

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, A-site was replaced by 1:1 of Ba2+ and La3+ 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 (PF-LMTO) method using both the generalized gradient approximation (GGA) and GGA plus on-site electron correlation effect (GGA+U). In GGA method, Ba2NRuO6 shows half-metallic (HM), semiconducting and metallic behavior for N = V, Cr, Fe, respectively, completely change to HM when A2 = BaLa. While, GGA+U method yields clearly HM state in all compounds, except for Ba2FeRuO6, which shows an insulating behavior. Also, the results of magnetic structures calculations reveal that the A2NRuO6 compounds show a ferrimagnetic (FI) nature if N = V and Cr, switch to ferromagnetic (FM) nature when N = Fe. The V3+, Cr3+, Fe3+ and Ru5+ ions are in high spin magnetic moments states due to the antiferromagnetic coupling N (3d)–O (2p)–Ru (4d).