Abstract
The pressure versus temperature phase diagram of the mixed-valence Eu 4As3 compound was determined by means of x-ray diffraction measurements using synchrotron radiation. The structural phase transition occurs at 343 K under ambient pressure with volume reduction and the transition temperature increases linearly with pressure up to about 5 GPa. The entropy change at this transition is estimated to be 41 J mol-1 K -1 from the Clausius-Clapeyron relation. The value is twice larger than the configuration entropy which is expected from a random arrangement of Eu3+ and Eu2+ ions in the thermally driven valence fluctuating state of Eu4As3. Moreover, a new structural phase was observed above 20 GPa at room temperature.
Original language | English |
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Pages (from-to) | S895-S899 |
Journal | Journal of Physics Condensed Matter |
Volume | 17 |
Issue number | 11 |
DOIs | |
Publication status | Published - 2005 Mar 23 |
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics