【摘要】 我们研究了室温下系列Sr掺杂的Y(Ba1 -xSrx) 2 Cu3 O7-δ陶瓷样品的63 ,65Cu核四极共振谱 .在YBa2 Cu3 O7-δ(Y1 2 3)中Sr2 + 的替代会在体系中产生化学压强效应 ,这种化学压强导致了CuO2 平面的Cu(2 )核四极共振信号向高频移动 ,而CuOx 链层的Cu(1 )核四极共振信号向低频移动 .随着Sr2 + 掺杂的增加 ,Cu(2 )和Cu(1 )的核四极共振峰的峰宽都明显地变宽 ,同时还观察到一个新的Cu核四极共振峰 .最后 ,我们给出了化学压强对超导转变温度的抑制的一些讨论 ,认为它与CuOx 链层氧原子的部分无序导致的载流子非均匀分布或局域化有关 .更多还原

【Abstract】 We report{63,65}Cu nuclear quadrupole resonance (NQR) spectra of Sr-substituted Y(Ba-{1-x}Sr-x)-2Cu-3O-{7-δ} at room temperature. The chemical pressure effect associated with Sr substitution leads to the results that the planar Cu(2) NQR signals are shifted to higher frequencies and the chain Cu(1) NQR signals are shifted to lower frequencies. With Sr substitution, the{63,65}Cu NQR linewidths increase significantly for both the Cu(2) plane site and Cu(1) chain site, and a new Cu NQR peak appears, as we expected, which originates from partial oxygen disorder in the CuO-x chain layers. We expect that T-c reduction with Sr substitution in Y123 is due to carrier inhomogeneous distribution and localization caused by the partial oxygen disorder in the CuO-x chain layers, or the suppression of the resonant tunneling between the CuO-2 planes.更多还原