TY  - JOUR
AU  - Shamblin, Jacob
AU  - Tracy, Cameron L.
AU  - Palomares, Raul I.
AU  - O'Quinn, Eric C.
AU  - Ewing, Rodney C.
AU  - Neuefeind, Joerg
AU  - Feygenson, Mikhail
AU  - Behrens, Jason
AU  - Trautmann, Christina
AU  - Lang, Maik
TI  - Similar local order in disordered fluorite and aperiodic pyrochlore structures
JO  - Acta materialia
VL  - 144
SN  - 1359-6454
CY  - Amsterdam [u.a.]
PB  - Elsevier Science85412
M1  - FZJ-2019-01583
SP  - 60 - 67
PY  - 2018
AB  - A major challenge to understanding the response of materials to extreme environments (e.g., nuclear fuels/waste forms and fusion materials) is to unravel the processes by which a material can incorporate atomic-scale disorder, and at the same time, remain crystalline. While it has long been known that all condensed matter, even liquids and glasses, possess short-range order, the relation between fully-ordered, disordered, and aperiodic structures over multiple length scales is not well understood. For example, when defects are introduced (via pressure or irradiation) into materials adopting the pyrochlore structure, these complex oxides either disorder over specific crystallographic sites, remaining crystalline, or become aperiodic. Here we present neutron total scattering results characterizing the irradiation response of two pyrochlores, one that is known to disorder (Er2Sn2O7) and the other to amorphize (Dy2Sn2O7) under ion irradiation. The results demonstrate that in both cases, the local pyrochlore structure is transformed into similar short range configurations that are best fit by the orthorhombic weberite structure, even though the two compositions have distinctly different structures, aperiodic vs. disordered-crystalline, at longer length scales. Thus, a material's resistance to amorphization may not depend primarily on local defect formation energies, but rather on the structure's compatibility with meso-scale modulations of the local order in a way that maintains long-range periodicity.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000424067100007
DO  - DOI:10.1016/j.actamat.2017.10.044
UR  - https://juser.fz-juelich.de/record/860940
ER  -