Structural and spectroscopic properties of Yb³⁺-doped MgAl₂O₄ nanocrystalline spinel.
Magnesium spinel (MgAl2O4) powders doped with Yb(3+) ions have been synthesized by a sol-gel method and heat-treated in the range of 700-1000 °C for 3 h. XRD patterns indicated that the powders have a cubic structure with high crystallite dispersion. Nanoparticles in the range of 10-30 nm are obtained as a function of the dopant concentration and sintering temperature. The main Yb(3+) zero-phonon line is located at 976 nm. The spectroscopic properties of the Yb(3+) ions are characterized by broad absorption spectroscopy and emission spectroscopy. Even at low temperature, the spectra reveal a strong distorted spinel lattice due to the high inversion rate between Mg(2+) tetrahedral sites and Al(3+) octahedral sites. The substitution of Mg(2+) ions by Yb(3+) ions favors the creation of Yb(3+) ion pairs which are observed in the cooperative luminescence spectra at around 500 nm. The luminescence decays are influenced by both the Yb(3+) content, the energy transfer between ions and by the presence of pairs and aggregates. Detailed analysis of the observed structural and spectroscopic measurements has been described in this manuscript.
Institute of Low Temperature and Structure Research, PAS, ul. Okolna 2, PL-50-422 Wrocław, Poland. R.Wiglusz@int.pan.wroc.pl.
Rafal J
RJ
Wiglusz
Georges
G
Boulon
Yannick
Y
Guyot
Malgorzata
M
Guzik
Dariusz
D
Hreniak
Wieslaw
W
Strek