Influence of NH₃ Flow Rate on the Ferromagnetic Properties of N-Doped SnO₂ Nanowires.

N-doped SnO₂ nanowires were synthesized via chemical vapor deposition in the presence of NH₃ gas with SnO₂ nanowires as the precursor. All samples exhibited room-temperature ferromagnetism (FM). X-ray diffraction measurement showed that the FM is intrinsic. Results of vibrating sample magnetometry indicated that FM decreased along with increasing NH₃ flow rate. Further analysis by X-ray photoelectron spectroscopy showed that the N atom was substituted at the lattice site of O, and NH₃ was chemisorbed in the surface of samples. The chemisorbed NH₃ was the dominant ingredient and main factor causing the significant decrease in FM. However, the FM of the samples after etching was enhanced due to the doped N atoms.