压力对不同Tc的Bi_(2+x)Sr_2Ca_(1-x)Cu_2O_y单晶超导电性的影响

EFFECTS OF HIGH PRESSURES ON Bi_(2+x) Sr_2 Ca_(1-x) Cu_2 O_y SUPERCONDUCTING SINGLE CRYSTALS WITH DIFFERENT T_c

在研究BiSrCaCuO超导单晶的过程中,我们发现材料的实际化学组分与理想的2212相配比组分有着一定的差别,正是这种成分偏析造成了样品的T_C与结构的不同。本文研究了在压力下不同T_C的样品随压力改变T_C的变化关系,发现偏析越大、T_C越低的样品的DT_C/dp也越大,而越接近理想组分,则dT_C/dp越趋于最小值。还可以从此推断出BiSrCaCuO理想单晶材料的T_C最佳值。压力对超导电性的这种影响可能与耦合链长的变化有关。

Under high pressures the Tc of Bi - Sr - Ca - Cu - O single crystals with different content segregation will change differently. We found that, samples with larger segregation and lower Tc exhibit higher dTc/dp. When the sample approaches to the ideal composition, it exhibit lowest dTc/dp . The high pressure effects on Tc may be closely related to the variation of bonding length .