Oscillations of the superconducting critical current in Nb-Cu-Ni-Cu-Nb   junctions
  We report on experimental studies of superconductor-ferromagnet layered structures. Strong oscillations of the critical supercurrent were observed with the thickness variation of the ferromagnet. Using known microscopic parameters of Ni, we found reasonable agreement between the period of oscillations and the decay of the measured critical current, and theoretical calculations. 
Y. Blum, A. Tsukernik, M. Karpovski, A. Palevski