The local structure of the highly "overdoped" 95 K superconductor Sr2CuO3.3 determined by Cu K X-ray absorption fine structure (XAFS) at 62 K in magnetically oriented samples shows that 1) the magnetization is perpendicular to the c axis; 2) at these levels of precision the Cu sublattice is tetragonal in agreement with the crystal structure; the O sublattice has 3) continuous -Cu-O- chains that orient perpendicular to an applied magnetic field; 4) approximately half-filled -Cu-O- chains that orient parallel to this field; 5) a substantial number of apical O vacancies; 6) O ions at some apical positions with expanded Cu-O distances; and 7) interstitial positions that imply highly displaced Sr ions. These results contradict the universally accepted features of cuprates that require intact CuO2 planes, magnetization along the c axis, and a termination of the superconductivity when the excess charge on the CuO2 Cu ions exceeds 0.27. These radical differences in charge and structure demonstrate that this compound constitutes a separate class of Cu-O-based superconductors in which the superconductivity originates in a different, more complicated structural unit than CuO2 planes while retaining exceptionally high transition temperatures.

中文翻译：

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Sr2CuO3.3的局部结构，它是一个无CuO2平面的95 K铜酸盐超导体。

通过Cu K X射线吸收精细结构（XAFS）在62 K的磁性取向样品中确定的高“超掺杂” 95 K超导体Sr2CuO3.3的局部结构表明：1）磁化垂直于c轴；2）在这些精度水平下，Cu亚晶格与晶体结构一致为四方晶；O亚晶格具有3）连续的-Cu-O-链，其垂直于所施加的磁场定向；4）平行于该磁场定向的大约一半填充的-Cu-O-链；5）大量的顶端O职位；6）在某些顶端位置的O离子具有扩大的Cu-O距离；7）间隙位置暗示了Sr离子的高度位移。这些结果与要求完整的CuO2平面，沿c轴磁化，当CuO2 Cu离子上的过量电荷超过0.27时，超导终止。这些电荷和结构上的根本差异表明，该化合物构成一类单独的基于Cu-O的超导体，其中超导性源自与CuO2平面不同，更复杂的结构单元，同时保留了异常高的转变温度。