Synchrotron X-ray spectroscopy study on the valence state in α- and β-YbAlB4 at low temperatures and high magnetic fields
The valence state of Yb ions in β-YbAlB4 and its polymorph α-YbAlB4 has been investigated by using X-ray absorption and emission spectroscopy in SPring-8 at temperatures from 2 to 280 K. The observed Yb valence is 2.78 ± 0.01 in β-YbAlB4 at 2 K by using the X-ray emission spectroscopy. The valence is found to gradually increase with increasing temperature toward the trivalent state, and the characteristic temperature of the valence fluctuation is expected to be about 290 K. We also found a small increase in the Yb valence (∼ 0.002) by applying a magnetic field of 32 T at 40 K to β-YbAlB4.
KeywordsValence fluctuation Heavy fermion High magnetic fields
Unable to display preview. Download preview PDF.
- N. Kanai, H. Hayashi, N. Kawamura, M. Mizumaki, Y. H. Matsuda, K. Kuga and S. Nakatsuji, Abstracts of the 15th International Conference on X-ray Absorption Fine Structure (XAFS15) (Beijing, China, 22–28 July, 2012).Google Scholar
- K. Ueda and Y. Onuki, Physics of Heavy Electron Systems (Shokabo, Tokyo, 1998).Google Scholar