The Cu2p XPS satellites of high-Tc superconductors axe compared with one of the Cu2+-containing compounds with different bonding type. The results show that Cu-O bonds in high-Tc superconductors are a blend of covalen...The Cu2p XPS satellites of high-Tc superconductors axe compared with one of the Cu2+-containing compounds with different bonding type. The results show that Cu-O bonds in high-Tc superconductors are a blend of covalent and ionic. The contribution of covalent bonding to Cu-O bonds is greater for high-Tc superconductors than for CuO. The average partial charge on oxygen (-δO) are calculated for a number of high-Tc superconductors. A correlation between Tc and -δO has been found, i.e. the Tc increases with decreasing -δO.展开更多
实验表明,在烧制 Bi-Sr-Ca-Cu-O 超导体时,压片两面用银片覆盖后热处理有利于110K 超导相生成,制得的超导体有较高的零电阻温度。XPS 分析表明,在烧制超导材料时 Bi 能优先挥发,其次是 Ca。有银片覆盖可减轻 Bi 等成份的挥发程度,因此...实验表明,在烧制 Bi-Sr-Ca-Cu-O 超导体时,压片两面用银片覆盖后热处理有利于110K 超导相生成,制得的超导体有较高的零电阻温度。XPS 分析表明,在烧制超导材料时 Bi 能优先挥发,其次是 Ca。有银片覆盖可减轻 Bi 等成份的挥发程度,因此有银片覆盖的超导体中 Bi、Sr、Ca 和 O 的相对浓度比无银片覆盖的超导体中的要高。展开更多
对于YBa_2Cu_3O_(~7)超导体的Ba 3d X光电子能谱(XPS)存在分裂(出现肩峰)的现象有很多不同的解释.Kohiki等认为主峰和肩峰分别代表晶格Ba^(2+)离子和金属Ba;Han等则认为它们分别代表Ba^(2+)离子和更高价态的Ba离子;Ji等提出超导体中存...对于YBa_2Cu_3O_(~7)超导体的Ba 3d X光电子能谱(XPS)存在分裂(出现肩峰)的现象有很多不同的解释.Kohiki等认为主峰和肩峰分别代表晶格Ba^(2+)离子和金属Ba;Han等则认为它们分别代表Ba^(2+)离子和更高价态的Ba离子;Ji等提出超导体中存在Ba^(2+)和Ba^((2-δ)+)两种离子;唐有祺等报道超导体存在体相钡、表面BaCO_3的钡和绝缘相中的钡,它们的Ba 3d_(5/2)结合能分别为777.8,779。7和781.5eV;展开更多
文摘The Cu2p XPS satellites of high-Tc superconductors axe compared with one of the Cu2+-containing compounds with different bonding type. The results show that Cu-O bonds in high-Tc superconductors are a blend of covalent and ionic. The contribution of covalent bonding to Cu-O bonds is greater for high-Tc superconductors than for CuO. The average partial charge on oxygen (-δO) are calculated for a number of high-Tc superconductors. A correlation between Tc and -δO has been found, i.e. the Tc increases with decreasing -δO.
文摘实验表明,在烧制 Bi-Sr-Ca-Cu-O 超导体时,压片两面用银片覆盖后热处理有利于110K 超导相生成,制得的超导体有较高的零电阻温度。XPS 分析表明,在烧制超导材料时 Bi 能优先挥发,其次是 Ca。有银片覆盖可减轻 Bi 等成份的挥发程度,因此有银片覆盖的超导体中 Bi、Sr、Ca 和 O 的相对浓度比无银片覆盖的超导体中的要高。
文摘对于YBa_2Cu_3O_(~7)超导体的Ba 3d X光电子能谱(XPS)存在分裂(出现肩峰)的现象有很多不同的解释.Kohiki等认为主峰和肩峰分别代表晶格Ba^(2+)离子和金属Ba;Han等则认为它们分别代表Ba^(2+)离子和更高价态的Ba离子;Ji等提出超导体中存在Ba^(2+)和Ba^((2-δ)+)两种离子;唐有祺等报道超导体存在体相钡、表面BaCO_3的钡和绝缘相中的钡,它们的Ba 3d_(5/2)结合能分别为777.8,779。7和781.5eV;