Investigation of the microstructure of the fine-grained YPO$_4$:Gd ceramics with xenotime structure after Xe irradiation

TL;DR

This study investigates the microstructural changes in xenotime-structured YPO$_4$:Gd ceramics after Xe ion irradiation, revealing partial amorphization and the effects of annealing on structural recovery.

Contribution

It provides new insights into the irradiation resistance and structural stability of YPO$_4$:Gd ceramics with xenotime structure under high-energy Xe ion exposure.

Findings

Amorphous layer depth increases insignificantly with fluence.

Volume fraction of amorphous structure rises from 20% to 70% with increased fluence.

Annealing restores approximately 80% of the initial XRD peak intensity.

Abstract

The paper reports on the preparation of xenotime-structured ceramics by the Spark Plasma Sintering (SPS) method. Phosphates Y$_{0.95}$Gd$_{0.05}$PO$_4$ (YPO$_4$:Gd) were obtained by the sol-gel method. The synthesized nanopowders are collected in large agglomerates 10-50 mkm in size. Ceramics has a fine-grained microstructure and a high relative density (98.67%). The total time of the SPS process was approximately 18 min. High-density sintered ceramics YPO$_4$:Gd with a xenotime structure were irradiated with Xe$^{+26}$ ions (E = 167 MeV) to fluences of $1\times10^{12}$-$3\times 10^{13}$ cm$^{-2}$. Complete amorphization at maximum fluence was not achieved. As the fluence increases, an insignificant increase in the depth of the amorphous layer is observed. According to the results of grazing incidence XRD (GIXRD), with an increase in fluence from $1\times10^{12}$-$3\times 10^{13}$ cm$^{-2}$, an increase in the volume fraction of the amorphous structure from 20 to 70% is observed. The intensity of XRD peak 200 YPO$_4$:Gd after recovery annealing (700$^\circ$C, 18 h) reached a value of ~80% of the initial intensity I0.