Properties of the amorphous-nanocrystalline Gd$_2$O$_3$ powder prepared by pulsed electron beam evaporation

An amorphous-nanocrystalline Gd$_2$O$_3$ powder with a specific surface area of 155 m$^2$/g has been prepared using pulsed electron beam evaporation in vacuum. The nanopowder consists of 20- to 500-nm agglomerates formed by crystalline nanoparticles (3–12 nm in diameter) connected by amorphous-nanocrystalline strands. At room temperature, the Gd$_2$O$_3$ nanopowder exhibits a paramagnetic behavior. The phase transformations occurring in the powder have been investigated using differential scanning calorimetry and thermogravimetry (40–1400$^\circ$C). The amorphous phase of the nanopowder is thermally stable up to a temperature of 1080$^\circ$C. It has been found that the amorphous phase has an inhibitory effect on the temperature of the polymorphic transformation from the cubic phase into the monoclinic phase. It has been revealed that, compared with the microcrystalline powder, the Gd$_2$O$_3$ nanopowder is characterized by a complete quenching of photoluminescence.