在LAS3000表面分析系统中用自制的低温样品台和清洁样品刮刀,获得了室温和130K下表面清洁的 YBa_2Cu_?O_(7-x)的X射线光电子谱。对超导与非超导样品中各元素的内层能级X射线光电子谱线进行分析比较.Ols出现双峰,其中高结合能峰属于O1,O4,低结合能峰属于O2,O3.室温下非超导样品的O2,O3高于-2价,Cu略低于+2价共价性极强,Y和Ba呈正常价态;低温下各元素价态无明显变化.室温下超导样品的O2,O3为-2价,Cu平均价高于+2价,离子性较强,存在Y和Ba的低价离子;低温下部分O2,O3价态升高,Cu价基本不变,Y和Ba的价进一步降低.两种样品中O1,O4价态绝对值都很低,反映了周围点阵缺陷的存在。
The XPS spectra of superconducting (123-orthorhombic structure) and non-superconducting (123-tetragonal structure) YBa_2Cu_3O_(7-x). ceramics were obtained at room temperature and 130 K in RIBER LAS 3000 surface analysis system, in which a sample cooling stage and a surface cleaning scraper, both made by the authors'own, were installed. No evidence of Cu~(3+) was found. The O1s shows double lines.They are attributed to O1 and O4 with higher binding energy and to O2 and O3 with lower binding energy respectively, and it was confirmed by calculation of SW-X_α method. The differences and changes in valence states of Y, Ba, Cu and O in both samples were discussed.
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