Light ion irradiation effects on stuffed Lu 2(Ti 2−xLu x)O 7−x/2 ( x = 0, 0.4 and 0.67) structures

Abstract

We have recently synthesized “stuffed” (i.e., excess Lu) Lu 2(Ti 2− x Lu x )O 7− x /2 ( x = 0, 0.4 and 0.67) compounds using conventional ceramic processing. X-ray diffraction measurements indicate that stuffing more Lu 3+ cations into the oxide structure leads eventually to an order-to-disorder ( O– D) transition, from an ordered pyrochlore to a disordered fluorite crystal structure. At the maximum deviation in stoichiometry ( x = 0.67), the Lu 3+ and Ti 4+ ions become completely randomized on the cation sublattices, and the oxygen “vacancies” are randomized on the anion sublattice. Samples were irradiated with 400 keV Ne 2+ ions to fluences ranging from 1 × 10 15 to 1 × 10 16 ions/cm 2 at cryogenic temperatures (∼77 K). Ion irradiation effects in these samples were examined by using grazing incident X-ray diffraction. The results show that the ion irradiation tolerance increases with disordering extent in the non-stoichiometric Lu 2(Ti 2− x Lu x )O 7− x /2.