Exchange coupling and current-perpendicular-to-plane giant   magneto-resistance of magnetic trilayers. Rigorous results within a   tight-binding single-band model
  It is shown that the current-perpendicular-to-plane giant magneto-resistance (CPP-GMR) oscillations, in the ballistic regime, are strongly correlated with those of the exchange coupling (J). Both the GMR and J are treated on equal footing within a rigorously solvable tight-binding single-band model. The strong correlation consists in sharing asymptotically the same period, determined by the spacer Fermi surface, and oscillating with varying spacer thickness predominantly in opposite phases. 
S. Krompiewski and M. Zwierzycki (Poznan), U. Krey (Regensburg)