The sample with nominal composition Bi_(1.8)Pb_(0.35)Sr_(2)Ca_(2)Cu_(3)O_(y) was prepared by solid state reaction method.Through the measurements of resistivity,dc.susceptibility,and the analysis of X-ray diffraction ...The sample with nominal composition Bi_(1.8)Pb_(0.35)Sr_(2)Ca_(2)Cu_(3)O_(y) was prepared by solid state reaction method.Through the measurements of resistivity,dc.susceptibility,and the analysis of X-ray diffraction and Energy Dispersive X-ray(EDX)microanalysis,we found that:(1)there is only one superconducting transition with transition temperature near 110K,its zero-resistance temperature(T_(ce))is as high as 106.5K,the diffraction pattern is similar to that of 2223 single phase(110K),but the cation ratio of Bi:Pb:Sr:Ca:Cu is near 25.8:5.74:18.43:19.53:30.50,i.e.,Bi_(2.5)Pb_(0.5)Sr_(2)Ca_(2)Cu_(3).We suppose that the 3223 phase is caused by intergrowth in the sample;(2)like the 1-2-3 phase material,the superconductivity of Bi-system is sensitive to oxygen content.We suppose that different oxygen content in the same crystal structure leads to the change of electronic structure,and so to great difference in the superconductivity.展开更多
X-ray Photcelectron Spectroscopy(XPS)was employed to study the single phase high-Tc superconductor YBa_(2)Cu_(3)O_(9-δ).Comparison.Of the observed valence band spectrum with the theoretical spectrum of Mattheiss is g...X-ray Photcelectron Spectroscopy(XPS)was employed to study the single phase high-Tc superconductor YBa_(2)Cu_(3)O_(9-δ).Comparison.Of the observed valence band spectrum with the theoretical spectrum of Mattheiss is given.The core level spectrum of Ba 3d5/2 was examined.The results of Y_(2)Cu_(2)O_(5)and Y_(2)BaCuO_(5)are also reported.展开更多
基金supported by the National Center for Research and Development on Superconductivity.
文摘The sample with nominal composition Bi_(1.8)Pb_(0.35)Sr_(2)Ca_(2)Cu_(3)O_(y) was prepared by solid state reaction method.Through the measurements of resistivity,dc.susceptibility,and the analysis of X-ray diffraction and Energy Dispersive X-ray(EDX)microanalysis,we found that:(1)there is only one superconducting transition with transition temperature near 110K,its zero-resistance temperature(T_(ce))is as high as 106.5K,the diffraction pattern is similar to that of 2223 single phase(110K),but the cation ratio of Bi:Pb:Sr:Ca:Cu is near 25.8:5.74:18.43:19.53:30.50,i.e.,Bi_(2.5)Pb_(0.5)Sr_(2)Ca_(2)Cu_(3).We suppose that the 3223 phase is caused by intergrowth in the sample;(2)like the 1-2-3 phase material,the superconductivity of Bi-system is sensitive to oxygen content.We suppose that different oxygen content in the same crystal structure leads to the change of electronic structure,and so to great difference in the superconductivity.
文摘X-ray Photcelectron Spectroscopy(XPS)was employed to study the single phase high-Tc superconductor YBa_(2)Cu_(3)O_(9-δ).Comparison.Of the observed valence band spectrum with the theoretical spectrum of Mattheiss is given.The core level spectrum of Ba 3d5/2 was examined.The results of Y_(2)Cu_(2)O_(5)and Y_(2)BaCuO_(5)are also reported.
