Ab initio investigation of magnetism and stability in Nb doped magnetite.

We investigated the magnetic alignment and formation energy of Niobium (Nb) in magnetite using density functional theory (DFT) calculations with both GGA + U and meta-GGA approaches. Our findings revealed that Nb exhibits greater stability when located at the octahedral site within the compound, although it remains metastable overall. By analyzing the deviation of the Nb-O bond from its expected ionic behavior, we have gained valuable insights into how Nb influences the magnetic moment in Nb-doped magnetite, which was determined to be 3.275 μ B /f.u. Moreover, examination of the bond angles has provided further justification for the observed reduction in this magnetic moment compared to pristine magnetite, where it is ∼ 4.0 μ B /f.u. This study yields significant insights into doped magnetite, a crucial industrial compound. • The stability and magnetism of niobium-doped magnetite are investigated. • Density functional theory based on GGA+ U and Meta-GGA functionals was used. • Nb dopant is more stable when substituting a Fe at the octahedral site. • Nb doping decreases the saturation magnetization of magnetite. • Nb-doped Fe 3 O 4 is metastable, while NbFe 2 0 4 constitutes the ground state. [ABSTRACT FROM AUTHOR]