Defect engineering techniques were employed to generate and remove oxygen vacancy defects in nanoparticles of Y2O3:Mn diluted magnetic oxide. These samples were prepared by thermal decomposition method followed by a series of thermal annealing in oxygen and forming gas. The X-ray absorption analysis reveals that O vacancies surrounding Mn and Y atoms were appreciably increased by forming-gas-annealing and decreased by oxygen-annealing, accompanied by enhanced and reduced saturation magnetization as demonstrated by magnetic measurements, respectively. The results revealed a strong correlation between magnetism and O vacancies and therefore strongly supported the bound magnetic polaron model for these high-k diluted magnetic oxides.

Correlation between Oxygen Vacancies and Magnetism in Mn-Doped Y2O3 Nanocrystals Investigated by Defect Engineering Techniques. T.S.Wu, Y.C.Chen, Y.F.Shiu, H.J.Peng, S.L.Chang, H.Y.Lee, P.P.Chu, C.W.Hsu, L.J.Chou, C.W.Pao, J.F.Lee, J.Kwo, M.Hong, Y.L.Soo: Applied Physics Letters, 2012, 101[2], 022408