Formation of graded vanadium oxide (V-O compound) under strong gravitational field

Jahirul Islam Khandaker, Makoto Tokuda, Yudai Ogata, Kamila Januszko, Tadao Nishiyama, Akira Yoshiasa, Tsutomu Mashimo

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Abstract

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 × 106G at 400°C for 24 h) on a V2O5 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 VO2 and V2O3 phases appeared and the amounts increased, while one of the V2O5 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 2.09eV) at strong gravity region in the graded structure showed transparent conductive oxide.

Original languageEnglish
Article number185905
JournalJournal of Applied Physics
Volume117
Issue number18
DOIs
Publication statusPublished - 2015 May 14
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Khandaker, J. I., Tokuda, M., Ogata, Y., Januszko, K., Nishiyama, T., Yoshiasa, A., & Mashimo, T. (2015). Formation of graded vanadium oxide (V-O compound) under strong gravitational field. Journal of Applied Physics, 117(18), [185905]. https://doi.org/10.1063/1.4921102