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以NH_4F作为F~-源,制备了一系列不同含F量的高T_cYBa_2Cu_3O(_7-x)F_v超导体,在名义F含量小于1.5mol范围内,其T_c值均比与之对照的不含F样品高2～6K.用XPS研究了这类含F材料表面和体相的化学态及其变化,根据同种化合物中不同元素间的结合能差和其它辅助实验结果,标识了每个元素不同化学态的光电子峰,并对各个峰的可能来源及其对应原子在结构中的位置和作用进行了讨论.结果揭示,表面和体相的化学态存在着较大差异.
A series of high T_cYBa_2Cu_3O (_7-x) F_v superconductors with different content of F were prepared with NH_4F as F ~ - source. The T_c values of the superconductors with high content of F were less than 1.5mol, High 2 ~ 6 K. The chemical state and the change of the surface and bulk phase of these F-containing materials were studied by XPS. According to the difference of the binding energies of different elements in the same compound and other auxiliary experimental results, State of the photoelectron peak, and the possible source of each peak and its corresponding atom in the structure of the position and role were discussed. The results revealed that the surface and the bulk chemical state there is a big difference.