Anisotropic Local Structure of SrFe2−xNixAs2 (x = 0.00, 0.16, and 0.23) Superconductor Probed by Polarized X-ray Absorption Fine Structure Measurements


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HACISALİHOĞLU M. Y., Tortora L., Tomassucci G., Simonelli L., Saini N.

Materials, vol.17, no.6, 2024 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 17 Issue: 6
  • Publication Date: 2024
  • Doi Number: 10.3390/ma17061301
  • Journal Name: Materials
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, CAB Abstracts, Communication Abstracts, Compendex, INSPEC, Metadex, Veterinary Science Database, Directory of Open Access Journals, Civil Engineering Abstracts
  • Keywords: iron-based superconductors, local structure, X-ray absorption spectroscopy
  • Recep Tayyip Erdoğan University Affiliated: Yes

Abstract

We have investigated the effect of the Ni substitution on the local structure and the valence electronic states of the (Formula presented.) (Formula presented.) (Formula presented.) (x = 0.00, 0.16, and 0.23) superconductor with a multi-edge extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopy. The As K-edge and Fe K-edge EXAFS measurements in the two polarizations (E‖ab and E‖c) show a clear change in the local structure with Ni concentration. The near-neighbor bondlengths and the related mean-square relative displacements (MSRDs) decrease as the Ni content increases. The polarized XANES spectra at the As, Fe and Ni K edges reveal a systematic change in the anisotropy of the valence electronic structure. The results suggest that the quasi 2D electronic structure of this system tends to become more isotropic as the Ni content increases. The local structure and the valence electronic states are discussed in the frame of the evolving electronic transport of the (Formula presented.) (Formula presented.) (Formula presented.) system.