Swift-heavy ion irradiation response and annealing behavior of A₂TiO₅ (A = Nd, Gd, and Yb)

Journal Article · 28 September 2017 · Journal of Solid State Chemistry

DOI: https://doi.org/10.1016/j.jssc.2017.09.028 · OSTI ID:1426170

Park, Sulgiye ^[1]; Tracy, Cameron L. ^[1]; Zhang, Fuxiang ^[2]; Palomares, Raul I. ^[3]; Park, Changyong ^[4]; Trautmann, Christina ^[5]; Lang, Maik ^[3]; Mao, Wendy L. ^[6]; Ewing, Rodney C. ^[1]

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1. Stanford Univ., CA (United States). Dept. of Geological Sciences
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
3. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Nuclear Engineering
4. Carnegie Inst. of Washington, Argonne, IL (United States). Geophysical Lab., High Pressure Collaborative Access Team (HPCAT)
5. GSI-Helmholtzzentrum fur Schwerionenforschung, Darmstadt (Germany); Technische Univ. Darmstadt (Germany)
6. Stanford Univ., CA (United States). Dept. of Geological Sciences; SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES)

The structural responses of A₂BO₅ (A = Nd, Gd, and Yb; B = Ti) compositions irradiated by high-energy Au ions (2.2 GeV) were investigated using transmission electron microscopy, synchrotron X-ray diffraction and Raman spectroscopy. The extent of irradiation-induced amorphization depends on the size of the A-site cation, with smaller lanthanides having less susceptibility to the accumulation of radiation damage. In the track-overlapping regime, complete amorphization is observed in all three compounds, despite the ability of Yb₂TiO₅ to incorporate a great deal of structural disorder into its initial defect-fluorite structure (Fm-3m). This is attributed to the high cation radius ratio (A:B = 2:1), which reduces the stability of the structure upon ion irradiation. The fully-amorphized samples were subsequently isochronally heated at temperature intervals from 100 °C to 850 °C. X-ray diffraction analysis indicated a similar damage recovery process in Nd₂TiO₅ and Gd₂TiO₅, where both compositions recover their original structures (Pnma) at 850 °C. In contrast, Yb2TiO5 exhibited recrystallization of a metastable, non-equilibrium orthorhombic phase at ~ 550 °C, prior to a transformation to the stable defect-fluorite phase (Fm-3m) at 625 °C. In conclusion, these compositional variations in radiation tolerance and thermal recovery processes are described in terms of the energetics of disordering during the damage and recrystallization processes.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Materials Science of Actinides (MSA); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC02-76SF00515; SC0001089; AC02-06CH1135; NA0001974; FG02-99ER45775; FC03-03NA00144
• OSTI ID: 1426170
• Alternate ID(s): OSTI ID: 1549229
• Journal Information: Journal of Solid State Chemistry, Vol. 258, Issue C; ISSN 0022-4596
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English