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

Abstract: MgO single crystals were implanted with 70keV C/N/O ions at room temperature with respective doses of 2×1016 and 2×1017 ions/cm2. All samples with high-dose implantation showed room temperature hysteresis in magnetization loops. Magnetization and slow positron annihilation measurements confirmed that room temperature ferromagnetism in O-implanted samples was attributed to the presence of Mg vacancies. Furthermore, the introduction of C or N played more effective role in ferromagnetic performance than Mg vacancies. Moreover, the magnetic moment possibly occurred from the localized wave function of unpaired electrons and the exchange interaction formed a long-range magnetic order. [Copyright &y& Elsevier]