Short- and medium-range order in Zr80Pt20 liquids

TitleShort- and medium-range order in Zr80Pt20 liquids
Publication TypeJournal Article
Year of Publication2011
AuthorsMauro NA, Wessels V, Bendert JC, Klein S, Gangopadhyay AK, Kramer MJ, Hao SG, Rustan GE, Kreyssig A, Goldman AI, Kelton KF
Journal TitlePhysical Review B
Date Published05/18
ISBN Number1098-0121
Accession NumberISI:000290710500003
Keywordsbinary-alloys, CU, ELECTROSTATIC LEVITATOR, metallic-glass, molecular-dynamics, ni, quasi-crystalline phase, total-energy calculations, wave basis-set, zr-pd

The atomic structures in equilibrium and supercooled liquids of Zr80Pt20 were determined as a function of temperature by in situ high-energy synchrotron diffraction studies of the levitated liquids (containerless processing) using the beamline electrostatic levitation (BESL) technique. The presence of a pronounced pre-peak at q similar to 1.7 angstrom(-1) in the static structure factor indicates medium-range order (MRO) in the liquid. The position and intensity of the pre-peak remain constant with cooling, indicating that the MRO is already present in the liquid above its melting temperature. An analysis of the liquid atomic structures obtained using the Reverse Monte Carlo method utilizing both the structure factor S(q) from x-ray diffraction experiments and the partial pair-correlation functions from ab initio molecular dynamics simulations show that the pre-peak arises from a Pt-Pt correlation that can be identified with icosahedral short-range order around the Pt atoms. The local atomic ordering is dominated by icosahedral-like structures, raising the nucleation barrier between the liquid and these phases, thus assisting glass formation.

URL<Go to ISI>://000290710500003
Alternate JournalPhys Rev BPhys Rev B