The important role of Mn3+ in the room-temperature ferromagnetism of Mn-doped GaN films

► Mn3+ substituted the Ga sites is believed to be the decisive factor in the origin of room-temperature ferromagnetism. ► The better room-temperature ferromagnetism is given with the higher Mn3+ concentration. ► The bound magnetic polarons (BMP) theory can be used to prove our room-temperature ferromagnetic properties. ► Higher annealing temperature (such as 1150 °C) is not expected because of the second phase MnxGay formation.