Structural features of nanocrystalline holmium oxide prepared by the thermal decomposition of organic precursors

摘要

Powders of nanostructured holmium oxide (C-Ho_2O_3) with the crystallite sizes ranging from 6 to 16 nm have been prepared in bulk from the thermal decomposition of holmium acetate and carbamide-containing complex of holmium as precursors at 600 and 700 °C The powders obtained have been investigated by X-ray diffraction, TEM, thermogravimetry, IR- and Raman spectroscopy. A comparison has been drawn between these and powdered holmium oxide with micron-sized crystallites prepared from the thermal decomposition of holmium chloride. The bcc lattice parameter of the oxides has been found to increase when the crystallite size decreases. It has been noted that the surface of air-exposed powders of holmium oxides is covered by products formed due to the chemisorption of atmospheric CO_2 and H_2O molecules.