Room-temperature ferromagnetism observed in C-/N-/O-implanted MgO single crystals

► The room temperature ferromagnetism was observed in C-/N-/O-implanted MgO single crystals. ► Mg vacancies as the origin of room temperature ferromagnetism in O-implanted MgO was demonstrated directly. ► The introduction of C or N play more effective role in ferromagnetic performance than Mg vacancies was proved in experiments. ► Bound magnetic polaron model was employed to explain the magnetic coupling in insulated MgO material.