The influence of hydrogen annealing on magnetism of Co-doped TiO2 films prepared by sol–gel method
The influence of hydrogen annealing on magnetism of Co-doped TiO2 films prepared by sol–gel method
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DOI：
10.1016/j.jmmm.2006.05.006
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发表时间：
2007
影响因子：
2.7
通讯作者：
Lingli Liu;Jinfeng Kang;Y. Wang;Hao Tang;L. Kong;Lei Sun;Xiu-Qing Zhang;R. Han
中科院分区：
文献类型：
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作者：
Lingli Liu;Jinfeng Kang;Y. Wang;Hao Tang;L. Kong;Lei Sun;Xiu-Qing Zhang;R. Han
采用溶胶-凝胶法在Si(001)衬底上制备了共掺杂的Ti02(CoxTi1−xO2，0.05⩽x⩽0.2)薄膜。在空气中热处理时，CoxTi1−xO2薄膜在室温下是非铁磁性的。然而，在流动的氢气气氛中进一步退火后，CoxTi1−xO2薄膜表现出室温铁磁性。磁化强度(M)与温度(T)的关系、X射线衍射(XRD)和X射线光电子能谱(XPS)都没有检测到氢化Co0.1Ti0.9O2薄膜中的Co团簇，这表明氢化Co0.1Ti0.9O2薄膜中的RTFM可能是本征的。但是，在氢化Co0.2Ti0.8O2薄膜中出现了金属Co，说明氢化Co0.2Ti0.8O2薄膜中的RTFM至少部分是由金属Co引起的。这些结果表明，氢退火可以在CoxTi1−xO2薄膜中产生室温铁磁性，但应谨慎设计，以避免在氢化CoxTi1−xO2薄膜中形成金属Co。
Co-doped TiO2(CoxTi1−xO2, 0.05⩽x⩽0.2) films have been prepared on Si (001) substrates by sol–gel method. When heat treated in air, CoxTi1−xO2films are non-ferromagnetic at room temperature. However, after further annealed in a flowing hydrogen atmosphere, CoxTi1−xO2films show room-temperature ferromagnetism (RTFM). Measurements of magnetization (M) vs. temperature (T), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) fail to detect Co clusters in the hydrogenated Co0.1Ti0.9O2films, suggesting that RTFM in the hydrogenated Co0.1Ti0.9O2films may be intrinsic. But, metal Co appears in the hydrogenated Co0.2Ti0.8O2films, showing that RTFM in the hydrogenated Co0.2Ti0.8O2films is as least partly due to metal Co. These results indicate that hydrogen annealing can produce room-temperature ferromagnetism in CoxTi1−xO2films, but it should be carefully designed to avoid the formation of metal Co in the hydrogenated CoxTi1−xO2films.