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.