Above room temperature ferromagnetism in Mn-ion implanted Si

Above room temperature ferromagnetic behavior is achieved in Si through Mn ion implantation. Three-hundred-keV Mn ⁺ ions were implanted to 0.1% and 0.8% peak atomic concentrations, yielding a saturation magnetization of 0.3 emu/g at 300 K for the highest concentration as measured using a SQUID magnetometer. The saturation magnetization increased by ∼2X after annealing at 800°C for 5 min. The Curie temperature for all samples was found to be greater than 400 K. A significant difference in the temperature-dependent remnant magnetization between the implanted p-type and n-type Si is observed, giving strong evidence that a Si-based diluted magnetic semiconductor can be achieved.