Direct observation of nanometer-scale amorphous layers and oxide crystallites at grain boundaries in polycrystalline Sr1−xKxFe2As2 superconductors

Lei Wang, Yanwei Ma, Qingxiao Wang, Kun Li, Xixiang Zhang, Yanpeng Qi, Zhaoshun Gao, Xianping Zhang, Dongliang Wang, Chao Yao, Chunlei Wang

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

We report here an atomic resolution study of the structure and composition of the grain boundaries in polycrystallineSr0.6K0.4Fe2As2superconductor. A large fraction of grain boundaries contain amorphous layers larger than the coherence length, while some others contain nanometer-scale crystallites sandwiched in between amorphous layers. We also find that there is significant oxygen enrichment at the grain boundaries. Such results explain the relatively low transport critical current density (Jc) of polycrystalline samples with respect to that of bicrystal films.
Original languageEnglish (US)
Pages (from-to)222504
JournalApplied Physics Letters
Volume98
Issue number22
DOIs
StatePublished - Jun 3 2011

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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