Accurate characterization of room-temperature long range magnetic order in GaN： Mn by magnetic force microscope

Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN： Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN： Mn layer, strong magnetic re- sponses were observed in the magnetic force microscopy （MFM） measurement, which revealed that the films were independ- ent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope （AFM） and MFM measure- ments covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN： Mn and gave a strong evidence of our GaN： Mn as the intrinsic diluted magnetic semiconductor （DMS）. The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide （DMO） systems.