高T_c超导化合物YBa_2Cu_3O_(6.5+δ)的Gibbs生成自由能

Standard Gibbs Free Energy of Formation of High T_c Superconducting Compound YBa_2Cu_3O_(6.5+δ)

用 CaF_2单晶作固体电解质,构成了氟化物-氧化物原电池(?)及(?)测得电池的可逆电动势为E_1=-0.063+1.43×10~4×T(V)E_2=0.089+1.68×10^(-4)×T(V)从而计算了由纯氧化物生成 BaCuO_2(011相)及 YBa_2Cu_3O_(6.5(?)δ)(123相)的标准生成自由能变化:△G_(011)~0=-10.5+1.8×10^(-3)×T(×4186.8J/mol)△G_(123+δ)~0=-19.0+(7.4-1.6×δ)×10^(-3)×T(×4186.8J/mol)在计算△G_(123+δ)~0时考虑了氧的非化学计量系数δ。

Galvenic cells(?)were constructed with single crystal CaF_2 as solid electrolyte and the cell EMF wasmeasured.The results were expressed asE_1=-0.063+1.43×10^(-4)×T,(V)E_2=0.089+1.68×10^(-4)×T,(V)The standard free energy change of formation of BaCuO_2 (011 phase)and YBa_2Cu_3O_((?)+δ)(123 phase)from the constituent oxides was estimated and expressed asΔG_(?)~0=-10.5+1.8×10^(-3)×T(×4188.8 J/mol)ΔG_(123+δ)~0=-19.0+(7.4-1.6×δ)×10^(-3)×T(×4186,8 J/mol)The oxygen non-stoichiometric fraction δ was taken into account in the estimationΔG_(123+δ)~0.