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M: Metallphysik
M 36: Diffusion und Punktdefekte I
M 36.3: Talk
Thursday, March 27, 2003, 10:45–11:00, IFW B
Ab-initio study of point defect energies of L12 intermetallics — •Wolfgang Püschl1, Jana Houserova1,2, 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.