TY - JOUR
T1 - Radiation effects in ferrate garnet
AU - Utsunomiya, S.
AU - Yudintsev, S.
AU - Ewing, R. C.
N1 - Funding Information:
The authors thank the staff of the IVEM-Tandem Facility at Argonne National Laboratory for assistance during the ion irradiation experiments. We thank John F. Mansfield, Corinna J. Wauchope, and Kai Sun of the Electron Microbeam Analysis Laboratory at University of Michigan for their support. This work was supported by US DOE, Office of Basic Energy Sciences under grant DE-FGO2-97ER45656.
PY - 2005/2/1
Y1 - 2005/2/1
N2 - Radiation effects in four synthetic ferrate garnets (A3B 2(XO4)3, Ia3d, Z = 8) were examined by ion beam irradiations with in situ observation (T = 298-873 K) using transmission electron microscopy (TEM) at the IVEM Tandem Facility at Argonne National Laboratory. The garnet compositions include: A = Ca, Gd, Th, and Ce; B = Zr, Fe. The critical amorphization temperatures (Tc), the temperature above which the target material cannot be amorphized due to dynamic annealing, were between 820 and 870 K. The amorphization doses at room temperature are between 0.17 and 0.19 dpa (displacement per atom), which is similar to that of silicate- and aluminate-garnets. The small variations in the amorphization dose and Tc of the different compositions suggest that radiation effects in ferrate garnets are structurally constrained. Qualitative analyses of the valence states of Ce and Fe in garnet before and after irradiation were completed using electron energy-loss spectroscopy (EELS). The Ce and Fe in the unirradiated garnet were dominantly trivalent and divalent, respectively. The characteristic peaks of Ce4+, at ∼5 eV higher energy for the M-edges, were present in unirradiated garnet as a minor peak, and the peaks did not disappear after complete amorphization, suggesting that the valence state did not change significantly. EELS analysis was conducted on a nearly pure andradite, Ca3Fe2Si3O12, which ideally contains only ferric iron. The andradite was amorphized at 0.18 dpa. EELS analysis revealed that some of ferric iron was converted to ferrous iron during the irradiation.
AB - Radiation effects in four synthetic ferrate garnets (A3B 2(XO4)3, Ia3d, Z = 8) were examined by ion beam irradiations with in situ observation (T = 298-873 K) using transmission electron microscopy (TEM) at the IVEM Tandem Facility at Argonne National Laboratory. The garnet compositions include: A = Ca, Gd, Th, and Ce; B = Zr, Fe. The critical amorphization temperatures (Tc), the temperature above which the target material cannot be amorphized due to dynamic annealing, were between 820 and 870 K. The amorphization doses at room temperature are between 0.17 and 0.19 dpa (displacement per atom), which is similar to that of silicate- and aluminate-garnets. The small variations in the amorphization dose and Tc of the different compositions suggest that radiation effects in ferrate garnets are structurally constrained. Qualitative analyses of the valence states of Ce and Fe in garnet before and after irradiation were completed using electron energy-loss spectroscopy (EELS). The Ce and Fe in the unirradiated garnet were dominantly trivalent and divalent, respectively. The characteristic peaks of Ce4+, at ∼5 eV higher energy for the M-edges, were present in unirradiated garnet as a minor peak, and the peaks did not disappear after complete amorphization, suggesting that the valence state did not change significantly. EELS analysis was conducted on a nearly pure andradite, Ca3Fe2Si3O12, which ideally contains only ferric iron. The andradite was amorphized at 0.18 dpa. EELS analysis revealed that some of ferric iron was converted to ferrous iron during the irradiation.
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U2 - 10.1016/j.jnucmat.2004.09.020
DO - 10.1016/j.jnucmat.2004.09.020
M3 - Article
AN - SCOPUS:12344299564
VL - 336
SP - 251
EP - 260
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
SN - 0022-3115
IS - 2-3
ER -