FABIÁN Martin Institute of Geotechnics SAS

Defects Related Properties in Nanocrystalline Ce1-xYxO2-δ (x ≤ 0.3) Solid Solutions Synthesized via High-energy Ball Milling

Co-authors GIRMAN Vladimír, MENZEL Dirk, ŠEPELÁK Vladimír

The cerium oxide (ceria, CeO2) and ceria based materials become one of the most interesting ceramics from both fundamental and practical point of view. There is number of their practical applications such as catalysts, oxygen sensors, UV/VIS absorbers, electrolytes for SOFC´s, etc. Within the present work, the nanostructured fluorite-type Ce1-xYxO2-δ solid solutions with the average crystallite size below 20 nm are produced by high-energy ball milling of the (1–x)CeO2 + (x/2)Y2O3 mixture for 90 min. The nanocrystalline nature of Ce1-xYxO2-δ as well as a decrease in both interplanar distances and unit cell parameters as a consequence of Y3+ incorporation into the ceria lattice are evidenced by XRD and HR-TEM. The increase of Y3+ concentration induces an increase in microstrains in host ceria lattice and suppresses the crystallite size growth. Raman spectroscopy indicates an increment in the concentration of intrinsic/extrinsic oxygen vacancies upon milling and Y3+ doping. Broad photoluminiscence spectra confirm formation of defects. The latter is further confirmed by variation in optical properties of the materials. The microstructure features result in an enhanced room-temperature ferromagnetism of the nanostructured Ce1-xYxO2-δ solid solutions.