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Title: Nanoscale structural heterogeneity in Ni-rich half-Heusler TiNiSn

The structural implications of excess Ni in the TiNiSn half-Heusler compound are examined through a combination of synchrotron x-ray and neutron scattering studies, in conjunction with first principles density functional theory calculations on supercells. Despite the phase diagram suggesting that TiNiSn is a line compound with no solid solution, for small x in TiNi{sub 1+x}Sn there is indeed an appearance—from careful analysis of the scattering—of some solubility, with the excess Ni occupying the interstitial tetrahedral site in the half-Heusler structure. The analysis performed here would point to the excess Ni not being statistically distributed, but rather occurring as coherent nanoclusters. First principles calculations of energetics, carried out using supercells, support a scenario of Ni interstitials clustering, rather than a statistical distribution.
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [1] ;  [2] ;  [2]
  1. Materials Department, University of California, Santa Barbara, California 93106 (United States)
  2. (United States)
  3. Diamond Light Source, Chilton, Oxfordshire OX11 0DE (United Kingdom)
  4. Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
Publication Date:
OSTI Identifier:
22308146
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DENSITY FUNCTIONAL METHOD; DISTRIBUTION; HEUSLER ALLOYS; INTERSTITIALS; NANOMATERIALS; NANOSTRUCTURES; NEUTRON DIFFRACTION; NICKEL COMPOUNDS; PHASE DIAGRAMS; SOLID SOLUTIONS; SOLUBILITY; SYNCHROTRON RADIATION; TIN COMPOUNDS; TITANIUM COMPOUNDS; X RADIATION