Showing papers by "Ronan McGrath published in 1998"
21 citations
TL;DR: In this article, the surface of the Al70 Pd21 Mn9 quasicrystal has been studied using STM, LEED and AES images from surfaces which have been sputtered and annealed to 875 K reveal 20-30 A protrusions that have been identified by others as Mackay-type clusters.
Abstract: The five-fold surface of the Al70 Pd21 Mn9 quasicrystal has been studied using STM, LEED and AES. STM images from surfaces which have been sputtered and annealed to 875 K reveal 20-30 A protrusions that have been identified by others as Mackay-type clusters. Higher-resolution images reveal substructures in these clusters having dimensions 2-3 A. Longer annealing times at 875 K produced large areas having flat terraces which were imaged with atomic resolution. the LEED pattern from this surface has sharp spots on a low background, and AES indicates that the surface is deficient in Mn relative to the bulk. For surfaces annealed to 1050 K for less than 2 hours, STM images indicate that cluster and terrace phases coexist, and a third phase having aligned arrays of clusters is identified which appears to be intermediate between the cluster and terrace phases.
12 citations
TL;DR: In this paper, the clock reconstruction of the Ni(100)(2×2)p4g-N system is shown to be removed by potassium adsorption using surface x-ray diffraction measurements.
Abstract: The “clock” reconstruction of the Ni(100)(2×2)p4g-N system is shown to be removed by potassium adsorption using surface x-ray diffraction measurements. The removal of the reconstruction is discussed in the framework of a simple model of induced surface stresses.
6 citations