Ion-beam-driven amorphization of Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} single crystals
- Pacific Northwest Lab., Richland, WA (United States)
- New Mexico Univ., Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences
Single crystals of Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2}, with 1% Nd substituted for La, were irradiated with 0.8 MeV Ne{sup +} and 1.5 MeV Kr{sub +} ions from 15 to 773 K. The irradiations were carried out using the HVEM-Tandem Facility at Argonne National Laboratory. The structural changes and the ion fluence for complete amorphization were determined by in situ transmission electron microscopy. The ion fluence for complete amorphization increased with temperature in two stages associated with defect annealing processes. The critical temperature for amorphization increased from {approximately}360 K for 0.8 MeV Ne{sup +} to {approximately}710 K for 1.5 MeV Kr{sup +}. During in situ annealing studies, irradiation-enhanced recrystallization was observed at 923 K. Spatially-resolved fluorescence spectra of the Nd ion excited with 488.0 mn laser excitation showed marked line-broadening toward the center of the amorphous regions. Initial measurements indicate the subtle shifts of the {sup 9}I{sub 9/2} groundstate energy levels can be measured by pumping directly into the excited state {sup 4}F{sub 3/2} manifold suggesting that the line broadening observed originates from a distribution of geometrically distorted Nd sites.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 10120513
- Report Number(s):
- PNL-SA-22718; CONF-931108-67; ON: DE94006219; TRN: 94:004526
- Resource Relation:
- Conference: Fall meeting of the Materials Research Society (MRS),Boston, MA (United States),29 Nov - 3 Dec 1993; Other Information: PBD: Nov 1993
- Country of Publication:
- United States
- Language:
- English
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