AF COUPLING OF COPPER COBALT MULTILAYERS WITH SMALL GRAIN-SIZE

We report the observation of oscillatory interlayer coupling for a ser ies of 50angstrom[Co12angstrom-Cutangstrom]15Cu50angstrom samples sput tered on glass substrates. The antiferromagnetic (AF) maxima are obser ved for t = 9 and 20 A. The particularities of our samples are their v ery small grain size (approximately 20 angstrom) without any preferent ial orientation and the sharpness of their interfaces (approximately 1 angstrom). These characteristics are favorable to strong magnetoresis tive effects which exceed 40% at 300 K and 90% at 4.2 K for our best s amples. Our results must be confronted by theoretical models that are only valid in the case of ideal single-crystals.