Laser ablation synthesis and characteristics of Tm-doped Gd2O3 nanoparticles

Abstract

Synthesis of nano-sized particles of thulium-doped gadolinium sesquioxide is reported. The nanopowder was obtained by laser ablation of solid target composed of a mixture of Tm2O3 and Gd2O3 powders using radiation of pulse-periodical CO2 laser. Morphological features, structural characteristics of nanoparticles and their densification behavior were investigated. It was shown that the as-synthesized nanopowder consists of loosely agglomerated particles with spherical shape and a diameter from 10 to 40 nm. It was revealed that the obtained sample is in the form of solid solution of Tm2O3 in Gd2O3 with monoclinic crystalline phase exhibiting the following lattice parameters: a = 14.095 Å; b = 3.571 Å c = 8.758 Å β = 100.182 °. Using X-ray diffraction analysis it was determined that, as opposed to other rare-earth sesquioxides (for instance, Y2O3 and Lu2O3), the phase transformation of monoclinic modification into cubic modification was not observed under thermal treatment at a temperature up to 1200 °C. This was also confirmed by an absence of stepwise variation in density of Tm:Gd2O3 compact which was evident for Gd2O3 sample prepared from powder with cubic phase and micro-sized particles.