掺Pb超导体(Bi_(2-x)Pb_x)Ca_(2.5)Nd_(0.5)Cu_2O_(8+y)的正电子寿命研究

The positron lifetime study of Pb doped(Bi_(2-x)Pb_x) Ca_(2.5)Nd_(0.5)Cu_2O_(8+y)superconductors

室温测量了（Ｂｉ２－ｘＰｂｘ）Ｃａ２．５Ｎｄ０．５Ｃｕ２Ｏ８＋ｙ超导体的正电子寿命与Ｐｂ含量的关系。在２２１２相发现随着Ｐｂ含量的增加正电子体寿命相应地减小。分析表明，这是由于Ｐｂ替换了Ｂｉ，使电子从ＣＵ－Ｏ面或其它晶位迁移到Ｂｉ－Ｏ层，并导致Ｂｉ－Ｏ层电子密度增加所致。

The positron lifetime has been measured as a function of doped Pb content in(Bi2-xPbx)Ca2.5Nd0.5Cu2O8+y.superconductors.It was found that positron lifetime decreased with the increase of Pb content in 2212 phase.It is believed that Pb substitutes for Bi,which makes some electrons transfer from Cu-O planes or other sites to Bi-O layers,increases the electron density at Bi-O layers and causes Tc to rise.