PLAN-VIEW MICROSTRUCTURES OF CO RU BILAYERS

Plan-view microstructures of two Co/Ru bilayers with a composition of [Co12 AngstromRu45 Angstrom](2) and [Co40 AngstromRu35 Angstrom](2) ha ve been studied by conventional and high resolution electron microscop y. Large differences in electron diffraction and image contrast betwee n the two bilayers were observed, which are recognized as the microstr uctural variations during the relaxation of large coherent planar stra ins when the Co layers wet coherently or semicoherently the Ru layers. For the [Co12 AngstromRu45 Angstrom](2) bilayer, the Co layers are un relaxed from the Ru layers; only one set of electron diffraction patte rns was observed, and the image consists of three types of contrasts w hich are closely related with either the generation and movement of mi sfit dislocations or large coherent strains. For the [Co40 AngstromRu3 5 Angstrom](2) bilayer, the Co layers are relaxed basically from the R u layers; two sets of electron diffraction patterns with double diffra ction spots were observed, and the image consists of small irregular a reas with moire fringe dots.