Nitrogen-induced Ferromagnetism in BaO

TL;DR

This study uses density functional theory to propose that nitrogen doping induces room temperature ferromagnetism in BaO, making it a potential material for spintronic applications.

Contribution

It demonstrates that N-doped BaO can be a half-metal with ferromagnetic order at room temperature, a novel finding for this material.

Findings

N doping induces ferromagnetism in BaO.

N-doped BaO is a half-metal with localized magnetic moments.

Potential for room temperature ferromagnetism in N-doped BaO.

Abstract

Density functional theory with local spin density approximation has been used to propose possible room temperature ferromagnetism in N-doped NaCl-type BaO. Pristine BaO is a wide bandgap semiconductor, however, N induces a large density of states at the Fermi level in the nonmagnetic state, which suggests magnetic instability within the Stoner mean field model. The spin-polarized calculations show that N-doped BaO is a true half- metal, where N has a large magnetic moment, which is mainly localized around the N atoms and a small polarization at the O sites is also observed. The origin of magnetism is linked to the electronic structure. The ferromagnetic(FM) and antiferromagnetic (AFM) coupling between the N atoms in BaO reveal that doping N atoms have a FM ground state, and the calculated transition temperature ($T_{C}$), within the Heisenberg mean field theory, theorizes possible room temperature FM in N-doped BaO. Nitrogen also induces ferromagnetism when doping occurs at surface O site and has a smaller defect formation energy than the bulk N-doped BaO. The magnetism of N-doped BaO is also compared with Co-doped BaO, and we believe that N has a greater potential for tuning magnetism in BaO than Co.