Annealing Effects on the Ferromagnetism of Ce0.97Co0.03O2-δ Compounds
With the investigation of the magnetic property of the Ce0.97CO0.03O2-δ powder, it is found that the as-sintered Ce0.97C00.03O2-δ is ferromagnetic at RT, and the saturation magnetic moments (Ms) are highly enhanced by Ar/H2, while sharply diminished by O2 annealing treatments. By means of X-ray photoelectron spectroscopy, Ce 3d and O ls spectra show that the Ar/H2 treatment partially reduced Ce4+ to Ce3+ as well as introducing additional oxygen vacancies (Vo), which contributes to the enhanced ferromagnetism observed in reduced Ce0.97C00.03o2-δ. The inereasement of Vo by Ar/H2 annealing is further proved by Raman spectra with a new Raman scattering peak appearing at the frenqueney of 570 cm-1. Likewise the decreased-Ms in O2 annealled sample is corresponding with much less Vo density. On all accounts Ms is found to be in direct ratio-dependent on Vo density in Ce0.97CO0.03O2-δ, which is well consistent with the F-center mediated ferromagnetism mechanism recently found in some transitional metal doped oxides, and thus is very important in understanding the mechanism of the ferromagnetism (FM) origination.
Co doped CeO2 ferromagnetism F-center exchange mechanism Ar/H2 annealing treatment
Y.Q.Song Q.H.Yang H.W.Zhang Y.X.Li L.R.Shah
State Key Laboratory of Electronic Films and Integrated Devices,University of Electronic Science and Department of Physics and Astronomy,University of Delaware,Newark,DE 19716,USA
国际会议
The 10th International Conference on Ferrites(2008中国国际铁氧体研讨会)
成都
英文
62-64
2008-10-10（万方平台首次上网日期，不代表论文的发表时间）