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M: Metallphysik

M 36: Diffusion und Punktdefekte I

M 36.3: Vortrag

Donnerstag, 27. März 2003, 10:45–11:00, IFW B

Ab-initio study of point defect energies of L1₂ intermetallics — •Wolfgang Püschl¹, Jana Houserova^1,2, Walter Wolf², Wolfgang Pfeiler¹, and Raimund Podloucky² — ¹Institut für Materialphysik der Univ. Wien, Strudlhofgasse 4, A-1090 Wien — ²Institut für Physikalische Chemie und Center for Computational Materials Science der Univ. Wien, Liechtensteinstr. 22a, A-1090 Wien

Based on a supercell ab-initio approach formation energies of antisite defects and vacancies were derived for the L1₂-ordered intermetallics Ni₃Al, Ni₃Ga, Pt₃Ga, Pt₃In. A thermodynamical treatment for point-like defects was then used for the calculation of temperature-dependent defect properties. In all cases antisite formation is favoured against vacancy formation but much stronger for the Ni compounds (0.75-1 eV) than for the Pt compounds (0.3 eV). For analyzing the results, bonding properties were investigated by calculating elastic and equilibrium properties for the perfectly ordered compounds.