Annealing temperature effects on the magnetic properties and induced defects in C/N/O implanted MgO

Virgin MgO single crystals were implanted with 70 keV C/N/O ions at room temperature to a dose of 2 × 1017/cm2. After implantation the samples showed room temperature hysteresis in magnetization loops. The annealing effects on the magnetic properties and induced defects of these samples were determined by vibrating sample magnetometer and positron annihilation spectroscopy, respectively. The experimental results indicate that ferromagnetism can be introduced to MgO single crystals by doping with C, N or introduction of Mg related vacancy defects. However, the Mg vacancies coexistence with C or N ions in the C-/N-implanted samples may play a negative role in magnetic performance in these MgO samples. The rapid increase of magnetic moment in O-implanted sample is attributed to the formation of new type of vacancy defects.