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})

Journal Article · Sat Feb 15 00:00:00 EST 2014 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2013.11.034· OSTI ID:22274221

Ohashi, Y.; Masubuchi, Y. ^[1]; Venkateshwarlu, D.; Ganesan, V. ^[2]; Yakhmi, J. V. ^[3]; Yoshida, T. ^[4]

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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)

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 niobium 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.

• OSTI ID: 22274221
• Journal Information: Journal of Solid State Chemistry, Vol. 210, 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); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

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