Evidence for carrier-induced high-TC ferromagnetism in Mn-doped GaN film

A GaN film doped with 8.2% Mn was grown by the molecular-beam-epitaxy technique. Magnetization measurements show that this highly Mn-doped GaN film exhibits ferromagnetism above room temperature. It is also revealed that the high-temperature ferromagnetic state is significantly suppressed below 10 K, accompanied by an increase of the electrical resistivity with decreasing temperature. This observation clearly demonstrates a close relation between the ferromagnetism with extremely high TC and the carrier transport in the Mn-doped GaN film.