Giant Magnetoresistance and Oscillatory MagneticCoupling of Evaporated and MBE-Grown Co/Ag Multilayers

Co/Ag multilayers grown by molecular beam epitaxy (MBE) exhibit giant magnetoresistance (MR). The spins of Co layers are aligned antiferromagnetically, which is the same as in Fe/Cr and Co/Cu. The MR ratio and saturation field showed oscillatory behavior as a function of Ag thickness with a period of about 16 Å. The MR ratio was obtained for [Co(6 Å)-Ag(25 Å)]×70, 16% at room temperature and 38% at 77 K.