Abstract
The powder synchrotron X-ray diffraction technique was used to study the thermal expansion behavior of the mixed valence layered compound, YbGa1.05Ge0.95 in the temperature range 3?1123 K. A surprising abrupt isosymmetric phase transition, accompanied by a dramatic volume increase (negative thermal expansion), was found at 5 K induced by a sudden Yb valence transition from +(2 + ε) toward +2. At high temperatures, the material undergoes a transformation to a highly disordered structure until it eventually collapses at 1123 K to a structure with isovalent Yb ions and flat Ga/Ge planes (AlB2 type).
Original language | English (US) |
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Pages (from-to) | 4498-4499 |
Number of pages | 2 |
Journal | Journal of the American Chemical Society |
Volume | 126 |
Issue number | 14 |
DOIs | |
State | Published - Apr 14 2004 |
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry