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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:42 |
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Conference: Bucharest University Faculty of Physics 2006 Meeting
Section: Atomic and Molecular Physics; Astrophysics
Title:
X-ray and FT-IR characterization of nanocrystalline Y3Al5O12 derived by a sol-gel method
Authors:
Elena Borca(1), M. Bercu(1), S. Georgescu(2), Andrea Stefan(2)
Affiliation:
1. Faculty of Physics, University of Bucharest, ROMANIA,
2. National Institute for Laser, Plasma and Radiation Physics, Bucharest, ROMANIA..
E-mail
lia_borca@yahoo.com
Keywords:
Nanocrystals, X-ray powder diffraction, FT-IR, YAG, sol-gel method
Abstract:
Nanocrystalline pure and rare earth doped yttrium aluminium garnet(YAG) are
promising materials for photonics.
Nano-sized YAG powders doped with Er3+ or Eu3+
were synthesized through nitrate-citrate sol-gel processing [1]. The powders
were obtained by drying the YAG gel followed by calcinations at 600oC.
The amorphous YAG precursor was then heat-treated at different temperatures from
900oC to 1100oC. The evolution of YAG phases was
investigated by X-ray powder diffraction (XRD) and Fourier Transform Infrared
Spectroscopy (FT-IR). The XRD pattern of powder heat-treated 3h at temperature
as low as 930oC showed the formation of cubic Y3Al5O12
well-crystallized phase. No intermediate phases were observed. Integral breadth
of diffraction line profile was used in order to determine the changes in
crystallite size with heat-treatment. The increasing of YAG crystallite size
from 20 to 50nm with annealing temperature increasing from 900oC to
1100oC was observed.
The FT-IR measurements were found to be consistent
with the YAG phase crystallization process observed by XRD. In YAG:Er and YAG:Eu
nanopowders the transition from amorphous to crystalline phase takes place in a
narrow interval of temperatures, between 900 and 930oC.
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