Physical properties of single-phase high-Tc superconductor YBa2Cu3O7

Abstract

Transport and thermodynamical properties as well as structural investigations in the well-characterized 90 K-class high-Tc superconductor YBa2Cu3O7 are presented, especially in relation to the fundamental mechanism of the high-Tc superconductivity. High-precision specific heat measurements around Tc=91.8 K reveal that the value of ΔC/Tc is 48±2 mJ/mol K2. This value results in the fact that the value of ΔC/γTc is 1.33, which is close to 1.43, the weak-coupling BCS value, provided that the coefficient, γ, of the linear term in the specific heat is 36±2 mJ/mol K2.