Magneto-optical studies of s,p-d exchange interactions in GaN:Mn with room-temperature ferromagnetism

Magnetic circular dichroism (MCD) spectra of a room-temperature ferromagnetic GaN:Mn film show that the film contains Ga1-xMnxN in which the band s,p-electrons interact with the d-electrons of the manganese ions. Both the magnetic field dependence and the temperature dependence of the MCD intensity show that Ga1-xMnxN is a paramagnetic diluted magnetic semiconductor (DMS). The ferromagnetism of the sample arises from an unidentified material that is not detected by the x-ray diffraction. This ferromagnetic material does not show the MCD signal, indicating that its electronic structure is different from that of Ga1-xMnxN. These results show that magneto-optical spectroscopy is indispensable to confirm the intrinsic ferromagnetism of DMS. (C) 2003 American Institute of Physics.