The Preparation And Research Of D0 Ferromagnetism In N-doped SnO₂ Nano-materials

Along with the development of semiconductor spintronic and potential applications, oxide diluted magnetic semiconductor becomes a research hotspot. For SnO2-based diluted magnetic semiconductor, SnO2 nano materials which are doped with 3d transition metal an minority un-doped ones are proved to have room temperature ferromagnetism. But the research on d0 ferromagnetism of SnO2 nano materials which are doped by non-magnetic anions is merely remaining at theoretical calculations. In our article, N doped SnO2 nano materials were synthesized through chemical vapor deposition, and the function of N doping amount towards the ferromagnetism of SnO2 nano materials was studied.N doped SnO2 nanowires were synthesized through annealing SnO2 nanowires under NH3 atmosphere, and the influence of annealing temperature, NH3 flux and annealing time on N doping amount and d0 ferromagnetic was investigated systematically. The XRD, XPS, VSM test results and analysis on sample surface after etching show that annealing process has no effects on morphology of SnO2 nanowires, but the lattice constant of SnO2 nanowires changes when the annealing temperature and NH3 flux are different, and the reason is that O atoms are replaced by N atoms. The synthesized N doped SnO2 nanowires show the intrinsic room temperature ferromagnetism, and the ferromagnetism is irrelevant to the surface oxygen vacancies of the nanowires. Annealing time has little influence on N doping amount of SnO2 nanowires and d0 ferromagnetism, but annealing temperature and NH3 flux both affect N doping amount and d0 ferromagnetism. The factors mainly comes into two point: surface adsorption of NH3 and substitution of N atoms. Surface adsorption of NH3 is the reason causing the rapid magnetism decrease, while the substitution of N atoms enhances the ferromagnetism of SnO2.In order to rule out effects of NH3 adsorption and have a further validation on influence of N atoms substitution to ferromagnetism of SnO2, Snx NyOz nano materials, the oxynitride of Sn, were synthesized. The origin of d0 ferromagnetism is analyzed after annealing treatment, the conclusions indicate that N atoms substitution can exactly enhance the ferromagnetism of sample. The experiment results of the article are specific proof of present related theoretical calculation results.