Room-Temperature Ferromagnetism of Cu-implanted GaN

Jong-Han Lee, In-Hoon Choi, Sangwon Shin, Sunggoo Lee, J. Lee, Chungnam Whang, Seng-Cheol Lee, Kwang-Ryeol Lee Lee, Jong-Hyeob Baek, Keun Hwa Chae, Jonghan Song  

1 MeV Cu2⁺ ion was implanted into GaN with a dose of 1x10¹⁷ cm⁻² at room temperature. After implantation, the samples were subsequently performed by rapid thermal annealing at 700, 800, and 900 °C for 5 min. Both nonmagnetic Cu ion implanted samples annealed at 700 and 800 °C exhibit the ferromagnetism at room temperature, and the saturation magnetization of these samples is estimated to be 0.057  B and 0.27  B per Cu atom from M-H curve, respectively. However, the sample annealed at 900 °C does not show ferromagnetism due to clustering of Cu during the annealing process.