Abstract
A systematic x-ray photoemission study of Eu and Eu core levels in the Eu—transition-metal compounds Eu, Eu, Eu, Eu, Eu and Eu is presented. The spectra in the divalent and trivalent compounds exhibit splittings into two components, caused by the occurrence of and configurations. For the divalent compounds Eu and Eu, this effect is due to final-state shakeup. For the trivalent compounds, the presence of both configurations is discussed in terms of both initial- and final-state effects. An estimate of the -configurational stability at the surface of the intermetallics indicates surface valence transition of the Eu ions to the lower valent state in these compounds. Experimental evidence for this behavior is given.
- Received 24 August 1982
DOI:https://doi.org/10.1103/PhysRevB.28.4342
©1983 American Physical Society