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Title: Formation of graded vanadium oxide (V–O compound) under strong gravitational field

Sedimentation of atoms induced under strong gravitational field gives a tool for controlling elemental compositions in condensed matter. We performed a strong-gravity experiment (0.397 × 10{sup 6 }G at 400 °C for 24 h) on a V{sub 2}O{sub 5} polycrystal using the high-temperature ultracentrifuge to examine the composition change and further the structure change. The graded composition structure of V and O was formed along gravity direction, where V increases and O decreases with gravity. It was found by the x-ray diffraction and Raman scattering method that VO{sub 2} and V{sub 2}O{sub 3} phases appeared and the amounts increased, while one of the V{sub 2}O{sub 5} phase decreased gradually along gravity direction. The X-ray absorption near edge structure spectra analysis identified the chemical valency decrease (+5 to +3). The UV-Vis absorption spectroscopy addressed the shifting in center of major absorption peak to longer wavelength (red shift) with the increase in gravitational field. The tail absorption peak (band gap 2.09 eV) at strong gravity region in the graded structure showed transparent conductive oxide.
Authors:
; ; ; ;  [1] ; ;  [2]
  1. Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555 (Japan)
  2. Faculty of Science, Kumamoto University, Kumamoto 860-8555 (Japan)
Publication Date:
OSTI Identifier:
22410203
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; ABSORPTION SPECTROSCOPY; ELECTRONIC STRUCTURE; ENERGY GAP; EV RANGE; GRAVITATIONAL FIELDS; RAMAN SPECTROSCOPY; RED SHIFT; SEDIMENTATION; ULTRACENTRIFUGES; VALENCE; VANADIUM OXIDES; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY