【摘要】 我们用双端振动簧法研究了系列在最佳掺杂区域Sr掺杂的Y(Ba1 -xSrx) 2 Cu3 O7-δ(Y1 2 3)样品从室温至液氮温区的音频内耗谱 .实验观察到未掺杂的Y1 2 3在 2 2 0K附近有一个相变内耗峰(标记为P3 ) ,随着Sr含量的增加 ,P3 峰的强度逐渐受到了抑制 ,而峰位没有系统的变化 .我们的结果不支持以前的氧有序无序解释 .结合近来在离子沟道实验[1 ] 以及核四极共振 ,和霍尔系数实验结果 ,在该温区也观察到转变 ,我们认为P3 与载流子行为的转变有关 ,而电子与晶格耦合在其中起着重要作用 .我们还研究了过掺杂区域P3 峰的变化 ,观察到P3 峰的强度向过掺杂区逐渐抑制 ,这也表明P3 峰同超导电性存在内在联系 .更多还原

【Abstract】 The internal friction spectra of partially Sr-substituted Y(Ba-{1-x}Sr-x)-2Cu-3O-{7-δ} (Y123) ceramics and Ca substituted Y-{1-x}Ca-xBa-2Cu-3O-{7-δ} were measured by the vibrating-reed method from liquid nitrogen temperature to room temperature at kilohertz frequencies. The intensity of the internal friction peak, which appears around 220K (labeled as P-3), decreases upon Sr doping while the peak position shows no systematic change. These results do not support the previous oxygen order-disorder explanation. With the increase of Ca content, the intensity of P-3 decreases and the peak position shifts toward low temperature. We present an approach relating this peak to the crossover in charge-carrier dynamics, and its evolution with impurity substitution is discussed in terms of release of internal strain and electron-phonon coupling.更多还原