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Title: Local structure around the flux pinning centers in superconducting niobium silicon oxynitride (Nb{sub 0.87}Si{sub 0.09}□{sub 0.04})(N{sub 0.87}O{sub 0.13})

The superconducting transition temperature of niobium silicon oxynitride (Nb{sub 0.87}Si{sub 0.09}□{sub 0.04})(N{sub 0.87}O{sub 0.13}) exhibits a gradual reduction from 16.8 K to around 11 K under an increasing applied magnetic field of up to 14 T. This relatively small T{sub c} reduction under an applied magnetic field suggests a robustness of its superconducting behavior in comparison to that in the parent niobium oxynitride. It was similar to the flux pinning effect observed in the large magnetic hysteresis of the niobium-silicon oxynitrides in our previous study. Both Si K-edge XANES and {sup 29}Si MAS-NMR indicated that the local structure of pinning centers around the silicon atoms close to cationic vacancies was similar to that of Si in amorphous SiO{sub 2} in the rock-salt structure of niobium oxynitride. - Graphical abstract: Potential energy scan of the Si atom in the most stable Si{sub 3}□O{sub 3}N cube around the vacancy in our preliminary simulation on niobium silicon oxynitride (Nb{sub 0.87}Si{sub 0.09}□{sub 0.04})(N{sub 0.87}O{sub 0.13}). A possible distortion of the Si atom was suggested from its octahedral towards tetrahedral position forming the local structure similar to that in amorphous SiO{sub 2}. Display Omitted - Highlights: • Critical current density was enhanced in superconducting niobiummore » oxynitride. • The robustness was introduced by forming rock-salt type niobium silicon oxynitride. • The silicon atom had a local structure similar to that in amorphous SiO{sub 2} in the rock-salt type lattice. • The local structure was formed together with its neighboring cationic vacancy. • It contributed as the flux pinning center in the NbSiNO.« less
Authors:
;  [1] ; ;  [2] ;  [3] ;  [4] ;  [1]
  1. Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)
  2. UGC-DAE-Consortium for Scientific Research, Khandwa Rd, Indore 452001, Madhya Pradesh (India)
  3. Homi Bhabha National Institute, Anushaktinagar, Mumbai-400 094 (India)
  4. EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)
Publication Date:
OSTI Identifier:
22274221
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 210; Journal Issue: 1; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ABSORPTION SPECTROSCOPY; HYSTERESIS; MAGNETIC FIELDS; MAGNETIC FLUX; NIOBIUM; NUCLEAR MAGNETIC RESONANCE; POTENTIAL ENERGY; SILICA; SILICON; SILICON OXIDES; SIMULATION; SUPERCONDUCTORS; TRANSITION TEMPERATURE; X-RAY SPECTROSCOPY