Microstructural investigation of Au ion-irradiated Eu-doped LaPO4 ceramics and single crystals

Sara E. Gilson, Volodymyr Svitlyk, Andrey A. Bukaemskiy, Jonas Niessen, Theresa Lender, Gabriel L. Murphy, Maximilian Henkes, Holger Lippold, Julien Marquardt, Shavkat Akhmadaliev, Christoph Hennig, Bjoern Winkler, Thorsten Tonnesen, Lars Peters, Cornelius Fischer, Nina Huittinen

Research output: Contribution to journalArticlepeer-review

Abstract

Ceramics and single crystals of LaPO4 monazite doped with Eu(III) were irradiated with 14 MeV Au5+ ions at three different fluences. Changes to crystallinity, local coordination environments, and topography were probed using grazing-incidence X-ray diffraction (GIXRD), vertical scanning interferometry (VSI), scanning electron microscopy (SEM), Raman, and luminescence spectroscopy. GIXRD data of the ceramics revealed fluence dependent amorphization. A similar level of amorphization was detected for samples irradiated with 5 × 1013ions/cm2 and 1 × 1014ions/cm2, whereas the sample irradiated with the highest fluence of 1 × 1015ions/cm2 appeared slightly less amorphous. VSI showed clear swelling of entire grains at the highest ion fluence, while more localized damage to grain boundaries was detected for ceramic samples irradiated at the lowest fluence. Single crystal specimens showed no pronounced topography changes following irradiation. SEM images of the ceramic irradiated at the highest fluence showed topological features indicative of grain surface melting. Raman and luminescence data showed a different degree of disorder in polycrystalline vs. single crystal samples. While changes to PO4 vibrational modes were observed in the ceramics, changes were more subtle or not present in the single crystals. The opposite was observed when probing the local Ln-O environment using Eu(III) luminescence, where the larger changes in terms of an elongation of the Eu-O (or La-O) bond and an increasing relative disorder with increasing fluence were observed only for the single crystals. The dissimilar trends observed in irradiated single crystals and ceramics indicate that grain boundary chemistry likely plays a significant role in the radiation response.

Original languageEnglish
Article number83
Journalnpj Materials Degradation
Volume8
Issue number1
DOIs
StatePublished - Dec 2024
Externally publishedYes

Funding

We acknowledge the use of the Ion Beam Center, HZDR for irradiations and the use of ROBL for GIXD measurements. We gratefully acknowledge the BMBF for funding through grant number 02NUK060.

FundersFunder number
Bundesministerium für Bildung und Forschung02NUK060

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