Structure and radiation effect of Er-stuffed pyrochlore Er2(Ti2−xErx)O7−x/2 (x = 0–0.667).

Er-stuffed pyrochlore series Er 2 (Ti 2− x Er x )O 7− x /2 ( x = 0, 0.162, 0.286, 0.424 and 0.667) were synthesized using conventional ceramic processing procedures. The structure of Er 2 (Ti 2− x Er x )O 7− x /2 is effectively tailored by the Er stuffing level ( x ). In order to study the radiation effect of Er-stuffed pyrochlores, irradiation experiments were performed with 400 keV Ne 2+ ions to fluences ranging from 5 × 10 14 to 3.0 × 10 15 ions/cm 2 at cryogenic condition. Irradiation induced microstructural evolution was examined using a grazing incidence X-ray diffraction technique. It is found that the irradiated layer of Er 2 (Ti 2− x Er x )O 7− x /2 undergoes significant lattice disordering and swelling at fluences of ⩽1.5 × 10 15 ions/cm 2 and amorphization at fluences of ⩾1.5 × 10 15 ions/cm 2 . The radiation effect depends strongly on the chemical compositions of the samples. Both the lattice swelling percentage and the amorphous fraction decrease with increasing x . The experimental results are discussed in the context of cation antisite defect. The defect formation energy which varies as a function of x is responsible for the difference in the structural behaviors of Er 2 (Ti 2− x Er x )O 7− x /2 under 400 keV Ne 2+ ion irradiation. [ABSTRACT FROM AUTHOR]