Andreev reflection in Bi_{1.8}Pb_{0.3}Sr_{1.9}Ca_2Cu_3O_x break junction
  The current-voltage characteristic (CVC) of break junction made from polycrystalline Bi_{1.8}Pb_{0.3}Sr_{1.9}Ca_2Cu_3O_x is investigated. The experimental CVC has hysteretic feature that reflects a part of a curve with negative differential resistance. The CVC is discussed within the framework of the Kummel-Gunsenheimer-Nicolsky theory considering multiple Andreev reflections in superconductor/normal-metal/superconductor junctions. 
D.M. Gokhfeld, D.A. Balaev, K.A. Shaykhutdinov, S.I. Popkov, M.I.   Petrov