Probing the effect of radiation damage on the structure of rare-earth phosphates

•Structural stability of La1-xYbxPO4 was studied using glancing angle XANES.•Loss of short- and long-range order in La1-xYbxPO4 due to ion-implantation observed.•High dose of Au− ions induced partial recrystallization of YbPO4 and La0.3Yb0.7PO4.•Glancing angle XANES spectra were sensitive to changes in the structure.•Annealing was found to result in the recrystallization of the damaged structure.

Synthetic analogues of naturally occurring monazite (REPO4; RE = La to Gd) and xenotime (RE′PO4; RE′ = Tb to Lu and Y) minerals have been identified as potential wasteforms for nuclear waste. High energy ion-implantation of crystalline materials simulates radiation-induced structural damage and allows for the radiation resistance of a crystal structure to be probed. The structural stability of Au− ion-implanted La1-xYbxPO4 materials was investigated using micro-X-ray diffraction (μ-XRD) and glancing angle X-ray absorption near-edge spectroscopy (GA-XANES) in this study. The long- and short-range order of La1-xYbxPO4 (x = 0, 0.3, 0.7, 1.0) is affected by ion-implantation and, thus, the materials are prone to structural damage. The structures of some members of the La1-xYbxPO4 series (x = 0.7 and 1.0) were observed to partially recover after being implanted with Au− ions to a high dose. The structures of all members of the La1-xYbxPO4 series were observed to recover from damage resulting from ion-implantation after annealing the materials at temperatures ≥300 °C.

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