Point Contact Studies of High T$\text{}_{c}$ Superconductors

Point contact spectroscopy experiments were performed on both single crystals Bi$\text{}_{2}$Sr$\text{}_{2}$CaCu$\text{}_{2}$O$\text{}_{8+y}$ and BiSrCaCuO/Ag sintered material using gold tips. The spectra exhibit tunneling structure, which are interpreted in terms of the energy gap structure 2Δ = 58 meV at 4.2 K. We observed the strong Andreev reflection of the Au-BiSrCaCuO/Ag boundary