A new homologous series of iron pnictide oxide superconductors (Fe 2As2)(Can+2(Al, Ti)nOy) (n = 2, 3, 4)

Hiraku Ogino, Kenji MacHida, Akiyasu Yamamoto, Kohji Kishio, Jun Ichi Shimoyama, Tetsuya Tohei, Yuichi Ikuhara

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    We have discovered a new homologous series of iron pnictide oxides (Fe 2As2)(Can+2(Al, Ti)nOy) (n = 2, 3, 4). These compounds have perovskite-like blocking layers between Fe2As2 layers. The structure of the new compounds is tetragonal with space groups of P4/nmm for n = 2 and 4 and P4mm for n = 3, which are similar to those of (Fe2As2)(Can+1(Sc, Ti)nOy) (n = 3, 4, 5) found in our previous study. Compounds with n = 3 and 4 have new crystal structures with three and four sheets of perovskite layers, respectively, including a rock salt layer in each blocking layer. The a-axis lengths of the three compounds are approximately 3.8 Å, which are close to those of FeSe and LiFeAs. (Fe2As 2)(Ca6(Al, Ti)4Oy) exhibited bulk superconductivity in magnetization measurement with Tc(onset) ∼ 36 K and resistivity drop was observed at ∼39 K. (Fe2As 2)(Ca5(Al, Ti)3Oy) also showed large diamagnetism at low temperatures. These new compounds indicate that considerable room still remains for new superconductors in layered iron pnictides.

    Original languageEnglish
    Article number115005
    JournalSuperconductor Science and Technology
    Issue number11
    Publication statusPublished - 2010 Nov 1

    ASJC Scopus subject areas

    • Ceramics and Composites
    • Condensed Matter Physics
    • Metals and Alloys
    • Electrical and Electronic Engineering
    • Materials Chemistry


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