Self-organized ferromagnetic nanowires in MgO-based magnetic tunnel junctions

•We examine defect-induced properties in MgO-based magnetic tunnel junctions.•Self-organized nanowires of magnesium vacancies can be formed in the MgO.•These nanowires can exhibit room-temperature ferromagnetism.

The focus of this study is to examine the distribution of defects and defect-induced properties in MgO-based magnetic tunnel junctions (MTJs). To this end, first-principles calculations were performed to estimate the electronic structures and total energies of MgO with various defects by using the Heyd–Scuseria–Ernzerhof (HSE06) hybrid functional. From connections drawn between the calculated results and previously reported experimental data, we propose that self-organized ferromagnetic nanowires of magnesium vacancies can be formed in MgO-based MTJs. This self-organization may provide the foundation for a comprehensive understanding of the conductivity, tunnel barriers and quantum oscillations of MgO-based MTJs. Further experimental verification is needed before firm conclusions can be drawn.