Materials Chemistry and Physics, Vol.147, No.3, 1092-1098, 2014
The effect of annealing on the electronic stability of an amorphous Zr70Pd30 alloy
Electronic stability analysis of amorphous Zr70Pd30 clusters upon transition from the as-quenched to an annealed state revealed a divergence in the interaction trends of the two atomic species. In the case of Zr-centered clusters, this transition involved a sizable shift in spin multiplicity from 8 to 4 accompanied by an 11% reduction in binding energy, the latter characterized by the reduction of Zr-e(g) contributions into orbitals involving Pd. In a qualitatively different transition mechanism, Pd cluster annealing caused the reduction of spin multiplicity from 6 to 4 expressed as a marginal 1% increase in binding energy and caused Pd centers to virtually disengage from interactions with Zr whilst increasing their majority e(g) populations in orbitals of the same species. Molecular orbital interactions translated into icosahedral or near-icosahedral coordination for Zr centers in both temperatures. Alongside differences in orbital interactions, a feature commonly expressed on both Zr- and Pd-centered clusters was revealed by the topology of the spin density which featured as sigma bonding of surface species on all of the low energy clusters studied. Some spin density sign reversal was also present and was tentatively taken to signify the onset of coordination saturation for both species. (C) 2014 Elsevier B.V. All rights reserved.
Keywords:Glasses;Non-crystalline materials;Ab initio calculations;Computer modelling and simulation;Monte Carlo simulation;X-ray scattering