An excess current in Bi2223–Ag contacts above the critical temperature

In contacts normal metal–superconductor Bi1.6Pb0.4Sr1.8Ca2.2Cu3O10 (Bi2223), the energy gap Δ(T) of the superconductor and the excess current Iexc(T) were measured by means of the Andreev spectroscopy. It is shown that the parameter Δ(T) turns to zero at the superconducting transition temperature of the cuprate, Tc ≈ 110 K, and the dependence Δ(T) follows the BCS theory; at the same time, the excess current Iexc(T) persists up to the temperature Tpair ≈ 180 K, significantly higher than Tc. The result obtained indicates a possible existence in Bi2223 of a wide temperature range Tc