A phase shift in the coupling in Co/sub 1-x/Ag/sub x/Cu/Co/sub 1-x/Ag/sub x/ systems

Upon the addition of Ag impurities in the Co layers of high quality molecular-beam-epitaxy grown Co/Cu(111) trilayers, the antiparallel coupling observed in the Co/Cu/Co trilayers for t/sub Cu/<12 /spl Aring/ has been transformed to a parallel coupling which appears as a significant shift in the phase of the interlayer coupling. In addition, the amplitude of the exchange coupling oscillations appears to decrease exponentially with increasing Cu layer thickness.