【摘要】 实验采用常压和高压分别制备出含铁的FexCu1 -xBaSrYCu2 Oy(x=0～ 1 )系列化合物 ,本文主要研究x =0 .5时样品的结构和超导电性 .测量结果显示 ,高压合成的样品均具有超导电性 ,对于x=0 .5的样品超导转变温度Tc(onset)～ 57K ,Tc(0 )～ 40K ,而常压合成的样品当Fe含量x >0 .3时均不超导 .为此 ,我们利用透射电子显微镜 (TEM)研究了该体系的微观结构特性 ,并通过电子能量损失谱(EELS)揭示出高压合成导致样品中载流子浓度明显高于常压样品 ,证明样品制备过程中高压有利于超导电性的形成 .同时对高压样品中的缺陷和局域晶体结构畸变进行了深入分析 .更多还原

【Abstract】 Two sets of Fe-xCu-{1-x}BaSrYCu-2O-y(0x1.0) samples have been synthesized under high pressure and the ambient condition, respectively. The structural features and superconductivity of these compounds have been systematically investigated by means of XRD, SAED, HREM, and EELS. All materials synthesized under high pressure are superconductors, while, materials with x>0.3, synthesized under the ambient condition, don′t show any superconductivity above 4.2K. EELS analyses indicate that the densities of charge carrier in the high-pressure-prepared samples are much higher than that in the samples prepared under the ambient condition. Some microstructural features and defect structure have been revealed by means of SAED and HREM. It is shown that the Fe doping at the Cu-O chains (Cu site) results in local atomic ordering. Several typical kinds of defect structures in the x0.5 sample have been extensively discussed.更多还原