Surface layer self diffusion in icosahedral Al-Pd-Mn quasicrystals

TitleSurface layer self diffusion in icosahedral Al-Pd-Mn quasicrystals
Publication TypeJournal Article
Year of Publication2007
AuthorsSamavat F, Gladys MJ, Jenks CJ, Lograsso TA, King BV, O'Connor DJ
Journal TitleSurface Science
Date PublishedDec
Type of ArticleProceedings Paper
ISBN Number0039-6028
Accession NumberISI:000251922700004
Keywordsal-pd-mn, aluminum, diffusion, energy-electron diffraction, IMPURITY DIFFUSION, ion scattering (LEIS), low energy, manganese, metallic surfaces, nmr, palladium, quasicrystals, temperature

The self diffusion of Mn and Pd in a single grain icosahedral Al69.9Pd20.5Mn9.6 quasicrystal has been determined by low energy ion scattering (LEIS). The diffusion was determined by depositing different elements (Pd, Mn) on the surface and measuring the rate of change in surface composition as a function of temperature by LEIS. The surface composition was monitored over the temperature range of 355-575 K for Mn and 440-745 K for Pd and compared to model calculations to allow the activation energy for diffusion to be determined. Activation energies of 0.20 +/- 0.01 eV for Mn and 0.64 +/- 0.03 eV for Pd have then been measured for self diffusion in i-Al-Pd-Mn, respectively. No deviation from Arrhenius behavior was detected in the temperature range covered by the present experiments. From the low values of activation energy we propose that this range of diffusion is phason related, reflecting the specific nature of the icosahedral structure. (c) 2007 Elsevier B.V. All rights reserved.

Alternate JournalSurf. Sci.