Bi_2Sr_2CaCu_(2-x)Sn_xO_(8+δ)系列超导体的XRD和XPS研究

XRD AND XPS STUDIES OF Bi_2Sr_2CaCu_(2-x)Sn_xO_(8+δ) SYSTEM

实验研究了Bi2 Sr2 CaCu2 -xSnxO8+δ的X射线衍射 (XRD)和光电子能谱 (XPS) .实验发现随着掺杂 (Sn)量的增加 ,晶格参数a和c都有所变化 ,O1s和Cu2 p芯能级谱也发生了变化 .实验结果表明 :在低掺杂量时 ,Sn主要呈二价态 ;而在高掺杂浓度时呈四价态 ;掺Sn对超导电性的影响与其他元素的掺杂不同 .这些实验结果支持化学环境在高温超导样品的电子结构中起着重要作用的结论 .

X\|ray diffraction and photoemission measurements have been carried out for Bi\-2Sr\-2CaCu\-\{2-\%x\%\}Sn\-\%x\%O\-\{8+\%δ\%\} system. With Sn doping, lattice parameters a and c change somewhat, O1s and Cu2p core levels shift differently in binding energy. From the experiment, we can deduce that the Sn ions are mostly in divalent state at small amount of doping, and in tetravalent state at high doping level. Doping with Sn may have less influence on the superconductivity than that with other elements. The results support the conclusion that chemical environment plays a major role in the shifts of all core levels in the high T \-c superconducting samples.