First-principles investigation of electronic and magnetic propertiess of double perovskites A2NRuO6 (A2 = Ba2, BaLa; N = V, Cr, Fe)

The electronic and magnetic properties of double perovskites A2NRuO6 (A2 = Ba2, BaLa; N = V, Cr, Fe) have been investigated using the first-principles density-functional theory (DFT) within the generalized gradient approximation (GGA) and GGA+U schemes. All compounds of (A2 = Ba2+) and doped (A2 = Ba2+La3+) crystallize in a cubic structure with (Fm-3m) space group. The GGA results of (A2 = Ba2+) predict half-metallic (HM), semiconductor and metallic character when (N = V, Cr, Fe), respectively which are completely stabilize at the HM nature within (A2 = Ba2+La3+) compounds. By including the exchange-correlation energy in GGA+U scheme, all compounds show a HM property, except for Ba2FeRuO6 which appears as an insulating material. In addition, GGGA and GGA+U calculations of spin magnetic moments suggest a ferrimagnetic (FI) character for A2NRuO6 (N = V and Cr), switch to a ferromagnetic (FM) nature when N = Fe. It is found that the two ions of N3+– Ru5+ (A2 = Ba2) and N3+– Ru4+ (A2 = BaLa) are governed by the antiferromagnetic interactions N3+ (3d)–O2– (2p)–Ru5+∕ Ru4+ (4d) in high∕ low spin magnetic moments states