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Fe Crystal (fe + crystal)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Temperature shift of the Fe2+ absorption band in LiNbO3:Fe crystal

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 13 2004
M. H. Yükselici
Abstract The temperature dependence of the Fe2+ absorption band of a strongly oxidized LiNbO3:Fe crystal is reported over the range from 25 to 350 °C, where the effect of temperature on the band is reversible. The band broadens and shifts to lower energy as temperature is increased. The rate at which the absorption peak energy decreases with increasing temperature is calculated as ,6.8 × 10,5 eV/°C from the slope of the straight-line fit to the temperature against peak position energy graph. We propose that the origin of the temperature shift is due to both a shift of the energetic position of impurities and the decrease of the band gap energy. The consistency between the calculated rate by the help of a simplified model which describes the shift of the band gap energy in the frame of the lattice dilation and the observed rate suggests that the lattice dilation might be responsible for the temperature shift of the band. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Localization and movement of native interstitials in chlorinated SrCl2:Fe crystals

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2007
D. Ghica
Abstract The formation of the electron trapped Fe+(IV) centre, produced by X-ray irradiation at 80 K and further annealing at temperatures of up to 700 K in chlorinated SrCl2:Fe crystals, has been investigated by Electron Paramagnetic Resonance. Our studies report the transformation of the monoclinic Fe+(III) centre into the axial Fe+(IV) centre above 450 K. The formation of the Fe+(IV) centre is attributed to the presence and thermally activated movement of neighbouring interstitial chlorine and alkali impurity Na+ ions. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]