Synthesis and characterization of Fe-Ti-Sb intermetallic compounds: Discovery of a new Slater-Pauling phase

N. Naghibolashrafi, S. Keshavarz, Vinay I. Hegde, A. Gupta, W. H. Butler, J. Romero, K. Munira, P. Leclair, D. Mazumdar, J. Ma, A. W. Ghosh, C. Wolverton

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21 Scopus citations


Compounds of Fe, Ti, and Sb were prepared using arc melting and vacuum annealing. Fe2TiSb, expected to be a full Heusler compound crystallizing in the L21 structure, was shown by XRD and SEM analyses to be composed of weakly magnetic grains of nominal composition Fe1.5TiSb with iron-rich precipitates in the grain boundaries. FeTiSb, a composition consistent with the formation of a half-Heusler compound, also decomposed into Fe1.5TiSb grains with Ti-Sb rich precipitates and was weakly magnetic. The dominant Fe1.5TiSb phase appears to crystallize in a defective L21-like structure with iron vacancies. Based on this finding, a first-principles DFT-based binary cluster expansion of Fe and vacancies on the Fe sublattice of the L21 structure was performed. Using the cluster expansion, we computationally scanned >103 configurations and predict a novel, stable, nonmagnetic semiconductor phase to be the zero-temperature ground state. This new structure is an ordered arrangement of Fe and vacancies, belonging to the space group R3m, with composition Fe1.5TiSb, i.e., between the full- and half-Heusler compositions. This phase can be visualized as alternate layers of L21 phase Fe2TiSb and C1b phase FeTiSb, with layering along the [111] direction of the original cubic phases. Our experimental results on annealed samples support this predicted ground-state composition, but further work is required to confirm that the R3m structure is the ground state.

Original languageEnglish (US)
Article number104424
JournalPhysical Review B
Issue number10
StatePublished - Mar 29 2016

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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