Pressure-induced valence changes in EuS and SmTe |
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| Authors: | G. Schmiester G. Wortmann G. Kaindl H. Bach F. Holtzberg |
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| Affiliation: | 1. Fachbereich Physik, Freie Universit?t Berlin , D-1000, Berlin , 33 , Germany;2. Ruhr-Universit?t Bochum, Fachbereich für Physik und Astronomie , D-4630 , Bochum , Germany;3. IBM Research Center , Yorktown Heights , N. Y. , 10598 , U. S. A. |
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| Abstract: | Abstract X-ray absorption spectroscopy was applied to study the pressure-induced valence changes in EuS and SmTe, which are divalent semiconductors of NaCl-type structure at ambient pressure. In both systems the Eu-LIII and Sm-LIII thresholds exhibit the onset of intermediate valencies of the rare earth ions at 15 GPa and 4 GPa, respectively. In EuS, one observes only a small increase of the valency within the investigated pressure range (36 GPa), while in SmTe a full transition to trivalency is observed above 20 GPa. The transition to the CsCl-Type high-pressure phase has no significant influence on the valence in both systems. |
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