CO_2、NH_3对YBa_2Cu_3O_(7-x)的结构及超导电性的影响

Effects of CO_2 and NH_3 on the structure and Superconductivity of YBa_2Cu_3O_(7-x)

以热重分析(TGA)、电阻测量和X射线衍射分析等方法,研究了CO_2与NH_3对YBa_2Cu_3O_(7-x)超导体结构稳定性及超导,电性的影响。当温度低于373K时,CO_2对YBa_2Cu_3O(7-x)的结构和超导电性无影响;当温度为523K时,CO_2使YBa_2Cu_3O_(7-x)的Tc下降;温度高于703K时,CO_2将很快破坏YBa_2Cu_3O_(7-x)的结构,并产生化学反应,生成新的化合物,在CO_2中存在的O_2与N_2对YBa_2Cu_3O(7-x)与CO_2的反应及反应产物的影响有较大差异。NH_3对YBa_2Cu_3O(7-x)结构稳定性的影响不大。

The effects of CO_2 and NH_3 on the structure and superconductivity of YBa_2Cu_3O_(7-x) have been studied by the means of thermogravimetric analysis (TGA), resistance measurement and X-ray diffraction. Below 373 K, no effe- cts of CO_2 on the structure and superconductivity of YBa_2Cu_3O_(7-x) can be dete- cted. At 523 K, Tc of YBa_2Cu_3O_(7-x) slightly shifts down after the sample heating in CO_2. Above 703 K, both the structure and superconductivity of YBa_2Cu_3O_(7-x) will be destroyed by CO_2 and producing chemical reactions. O_2 and N_2 existing in CO_2 cause different influences to the chemical reactions and reactants. The effect of NH_3 on the structure stability of YBa_2Cu_3O_(7-x) is very little.