In situ Raman spectroscopy of pressure-induced phase transformations in polycrystalline TbPO4, DyPO4, and GdxDy(1–x)PO4 [In situ Raman spectroscopy of pressure-induced phase transformations in DyPO4 and GdxDy(1–x)PO4]
Abstract Xenotime Dy PO 4 and Gd x Dy (1− x ) PO 4 ( x = 0.4, 0.5, 0.6) (tetragonal I 4 1 amd zircon structure) have been studied at ambient temperature under high pressures inside a diamond anvil cell with in situ Raman spectroscopy. The typical Raman‐active modes of the xenotime structure were observed at low pressures and the appearance of new Raman peaks at higher pressures indicated a phase transformation to a lower symmetry structure—likely monoclinic. Raman mode softening was observed, resulting in a line crossing at approximately 7‐8 GPa for each material and preceding the phase transformation. The onset of phase transformation for Dy PO 4 occurred at a pressure of 15.3 GPa. Dy PO 4 underwent a reversible phase transformation and returned to the xenotime phase after decompression. The transformation pressures of the solid solutions (Gd x Dy (1− x ) PO 4 ) were in the range 10‐12 GPa. The Gd x Dy (1− x ) PO 4 solid solutions yielded partially reversible phase transformations, retaining some of the high‐pressure phase spectrum while reforming xenotime peaks during decompression. The substitution of Gd into Dy PO 4 decreased the transformation pressure relative to pure Dy PO 4 . The ability to modify the phase transformation pressures of xenotime rare‐earth orthophosphates by chemical variations of solid solutions may provide additional methods to improve the performance of ceramic matrix composites.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1464024
- Alternate ID(s):
- OSTI ID: 1416390
- Journal Information:
- Journal of the American Ceramic Society, Vol. 101, Issue 6; ISSN 0002-7820
- Publisher:
- American Ceramic SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Influence of citrate on phase transformation and photoluminescence properties in LaPO 4 and LaPO 4 :Eu
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journal | January 2018 |
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