Ion-irradiation-induced amorphization ofLa2Zr2O7

Abstract

The isometric pyrochlore structure, A 2 B 2 O 7 , is generally susceptible to radiation damage, but certain compositions are remarkably resistant to radiation damage. In the binary system Gd 2 (Ti 2Ϫx Zr x )O 7 , the radiation resistance increases dramatically with the substitution of Zr for Ti, until the pure end member Gd 2 Zr 2 O 7 cannot be amorphized, even at doses as high as ϳ100 dpa. Although zirconate pyrochlores are generally considered to be radiation resistant, we report results for the amorphization of a zirconate pyrochlore La 2 Zr 2 O 7 by ion beam irradiation ͑ϳ5.5 dpa at room temperature͒. The critical amorphization temperature T c is low, ϳ310 K. The susceptibility to ion-beam-induced amorphization and structural disordering for zirconate pyrochlores is related to the structural deviation from the ideal fluorite structure, as reflected by the x parameter of the O 48f .

Lanthanum pyrochlores and the effect of yttrium addition in the systems La2−xYxZr2O7 and La2−xYxHf2O7

“…However, the recoil from alpha-decay places strain on the lattice, which in some compositions causes the structure to become amorphous, while others are radiation tolerant [15][16][17][18]. The objective of this work is to study systematic yttrium addition on the La 2 Hf 2 O 7 , and La 2 Zr 2 O 7 systems.…”

Interplay between atomic disorder, lattice swelling, and defect energy in ion-irradiation-induced amorphization of SiC

“…In some materials (e.g. pyrochlores), collision cascades produce point defects only [8], but their accumulation can lead to crystalline-to-crystalline phase transition [9] and even to complete amorphization [9,10]. In several other materials, single collision cascades can produce direct impact amorphization that leads to a complete amorphization by percolation [11].…”

Molecular environmental science using synchrotron radiation:Chemistry and physics of waste form materials

“…The mechanism and structural properties leading to superior radiation resistance [4] of these same pyrochlore materials also has been characterized. Ion-beam irradiation of an increasingly Zr-substituted series of pyrochlores has been studied by NEXAFS and XPS to yield detailed structural information.…”

“…Local structural properties of glasses are not easily studied by conventional techniques because they possess no long-range order. In glass matrices, boron forms three-dimensional, rigid tetrahedral BO 4 5-units with sp 3 hybridization and two-dimensional, trigonally coordinated BO 3 3-moieties with sp 2 hybridization. The ratio of tetrahedral sp 3 to trigonal sp 2 boron strongly affects the properties of glass matrices because trigonal boron greatly reduces glass durability [5][6][7].…”