Point-contact studies of high-temperature superconductor $\mathrm{Y}\mathrm{B}{\mathrm{a}}_2\mathrm{C}{\mathrm{u}}_3{\mathrm{O}}_{7-\delta }$

Point-contacts formed by the high-temperature superconductor $\rm YBa_2Cu_3O_{7-\delta}$ prepared by cryochemical technique, and a noble metal Ag or Cu) are investigated. The maximum value of the energy gap $\Delta\simeq 40~meV$andtheratio$2\Delta/kT_c\simeq 12$ are obtained. It is found that along certain crystallographic axes of the superconductor under investigation, the electrical resistivity $\lesssim {10}^{-5}\mathrm{\Omega }\cdot cm$.