Temperature Dependence of the Local Structure and Iron Magnetic Moment in the Self-Doped CaKFe4As4Iron-Based Superconductor

F. Stramaglia, G. M. Pugliese, L. Tortora, L. Simonelli, C. Marini, W. Olszewski, S. Ishida, A. Iyo, H. Eisaki, T. Mizokawa, N. L. Saini*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Temperature-dependent Fe K-edge extended X-ray absorption fine structure (EXAFS) and Fe Kβ X-ray emission spectroscopy (XES) measurements are used to study the local structure and local Fe magnetic moment in the self-doped CaKFe4As4 superconductor. The local Fe-As and Fe-Fe bond lengths show thermal expansion similar to the one found in other iron-based superconductors. The arsenic height from the Fe-Fe plane changes anomalously with a sharp decrease in the vicinity of the superconducting transition temperature. The Fe Kβ XES reveals that Fe in CaKFe4As4 is in the low spin state, and the local magnetic moment decreases sharply while the sample is cooled across the transition temperature. The results indicate importance of the magnetoelastic coupling in the superconductivity with a key role of interlayer atomic correlations in these materials.

Original languageEnglish
Pages (from-to)10810-10816
Number of pages7
JournalJournal of Physical Chemistry C
Volume125
Issue number19
DOIs
Publication statusPublished - 2021 May 20

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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