New σ-phases in the Nb-X-Ga and Nb-X-Al systems (X = Ru, Rh, Pd, Ir, Pt, and Au)

Elizabeth M. Carnicom, Weiwei Xie, Tomasz Klimczuk, R. J. Cava

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1 Scopus citations


Previously unreported σ-phases in the ternary niobium-based systems Nb-X-Ga for X = Ru, Rh, Pd, Ir, Pt, Au, and Nb-X-Al for X = Ir, and Pt are presented, prepared by arc-melting followed by annealing at 1000 °C for 1 week. The phases are primitive tetragonal (P42/mnm, no. 136) with lattice parameters of a = 9.8336(2)-9.9432(1) Å and c = 5.1098(1)-5.1718(1) Å. Refinements of the single crystal X-ray diffraction data for the Ru and Ir containing materials gave the formulas Nb20Ru5Ga5 and Nb20Ir4Ga6, showing mixing of X/Ga on the crystallographic 8i2 and 2a sites of the structure, a type of disorder frequently found in σ-phases. We present a graphical classification for ternary σ-phases that places our materials in context with previous materials. The materials do not show evidence of bulk superconductivity above 2 K. Synthesis of equivalent Ta-based σ-phases was attempted but they were not found.

Original languageEnglish (US)
Pages (from-to)14158-14163
Number of pages6
JournalDalton Transactions
Issue number41
StatePublished - 2017

All Science Journal Classification (ASJC) codes

  • Inorganic Chemistry


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