Ion-beam-induced amorphization and order-disorder transition in the murataite structure
- Department of Geological Sciences, Department of Nuclear Engineering and Radiological Sciences, and Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)
Murataite (A{sub 3}B{sub 6}C{sub 2}O{sub 22-x/2},F43m), a derivative of an anion-deficient fluorite structure, has been synthesized as different polytypes as a result of cation ordering. Ion-beam-induced amorphization has been investigated by 1-MeV Kr{sup 2+} ion irradiation with in situ transmission electron microscopy. The critical amorphization dose was determined as a function of temperature and the degree of structural disordering. A lower critical amorphization temperature ({approx}860 K) was obtained for the disordered murataite as compared with that of the murataite superstructure (930 to 1060 K). An ion-beam-induced ordered murataite to a disordered fluorite transition occurred in the murataite superstructure, similar to that observed in the closely related pyrochlore structure-type, A{sub 2}B{sub 2}O{sub 7}. The ion-beam-induced defect fluorite structure is more energetically stable in the murataite structure with a higher degree of structural disordering, as compared with the murataite superstructure. This suggests that the degree of intrinsic structural disorder has a significant effect on the energetics of structural disordering process; this affects the tendency toward the order-disorder structural transition for fluorite-related compounds and their response to ion-beam-induced amorphization.
- OSTI ID:
- 20711718
- Journal Information:
- Journal of Applied Physics, Vol. 97, Issue 11; Other Information: DOI: 10.1063/1.1926394; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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