Oscillatory magnetic exchange coupling through thin copper layers

Abstract

Confirming theoretical predictions more than 25 years old, we show that Co slabs are indirectly exchange coupled via thin Cu layers with a coupling that alternates back and forth between antiferromagnetic and ferromagnetic. Four oscillations are observed with a period of \ensuremath{\simeq}10 \AA{}. Moreover, the antiferromagnetically coupled Co/Cu superlattices exhibit extraordinarily large saturation magnetoresistances at 300 K of more than 65%.