| Autor: |
Balodhi, Ashiwini, Torres, James, Juneja, Rinkle, Chang, Kelvin B., Brady, Allen, Chakrapani, Sunil K., Lindsay, Lucas R., Hermann, Raphael P., Zevalkink, Alexandra |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 11/7/2022, Vol. 132 Issue 17, p1-8, 8p |
| Abstrakt: |
The tetragonal fluoro-scheelite Li R E F 4 compounds (R E = rare earth) have been shown to exhibit a variety of useful optical and magnetic properties. While LiYF 4 has been widely studied, many of the fundamental thermodynamic properties of other members of this family remain unknown. Here, we report the complete elastic tensors ( C ij ) of single-crystalline LiYF 4 , LiTbF 4 , and LiGdF 4 using resonant ultrasound spectroscopy and density functional theory (DFT). We compare the results for LiYF 4 with prior experimental results using time-of-flight ultrasound methods. This is the first report, however, of the experimental elastic tensors of LiTbF 4 and LiGdF 4. The present results point to a softening of the elastic moduli of the Li R E F 4 system when Y is replaced by the larger ionic radius of Tb or Gd. Furthermore, we find that just 0.3% doping with Nd on the Y site also leads to a slight softening of the moduli. The variation of the elastic moduli as a function of temperature up to 216 ° C was also measured. A nearly linear softening of all seven independent elastic moduli was observed with increasing temperature. Phonon dispersions and phonon density of states obtained by DFT support the experimental finding of a significantly higher sound velocity due to lighter Y atoms in LiYF 4 , as compared to heavier LiTbF 4 and LiGdF 4. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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