Superconducting Properties of Cuprate High‐Tc Superconductors

Due to the layering of the crystal structures, the superconducting properties of cuprate high-Tc superconductors are anisotropic. The characteristic length scales (coherence length and penetration depth) are considered. Measured values of the energy gap of various cuprate superconductors are tabulated. The magnetic phase diagram of cuprate high-Tc superconductors is compared with that of metallic Type II superconductors. A characteristic feature of the high-Tc superconductors is the existence of an irreversibility line well below the upper critical field. Above the irreversibility line, the pinning force for the vortices is negligible, and hence the material is a superconductor with vanishing critical current density. Values of the anisotropic upper and lower critical fields of various cuprate superconductors are presented. Finally, the critical current densities and their limitations (weak-link behavior) are discussed.