High-magnetic-field X-ray absorption spectroscopy of field-induced valence transition in EuNi(SiGe)

Matsuda, Yasuhiro*; Inami, Toshiya; Owada, Kenji; Murata, Yuto*; Nojiri, Hiroyuki*; Murakami, Yoichi*; Mitsuda, Akihiro*; Wada, Hirofumi*; Miyazaki, Hiroshi*; Harada, Isao*

Journal of the Physical Society of Japan, 77(5), p.054713_1 - 054713_7, 2008/05

https://doi.org/10.1143/JPSJ.77.054713

The magnetic-field-induced valence transition in EuNi(SiGe) (x=0.82, 0.85) has been studied by X-ray absorption spectroscopy at low temperatures. The field dependence of the Eu valence is directly observed for the first time. We find a significant decrease in the valences at high magnetic fields above 40 T. The valence of Eu changes from v = 2.75 at a zero field to v = 2.33 at 40 T for x = 0.82. The results are analyzed using a theoretical model. The hybridization parameter V between the Eu and Eu states and the energy separation are determined, which are crucial for quantum mechanical mixing.

High field X-ray diffraction study on a magnetic-field-induced valence transition in YbInCu

Matsuda, Yasuhiro*; Inami, Toshiya; Owada, Kenji; Murata, Yuto*; Nojiri, Hiroyuki*; Murakami, Yoichi*; Ota, Hiroto*; Zhang, W.*; Yoshimura, Kazuyoshi*

Journal of the Physical Society of Japan, 75(2), p.024710_1 - 024710_5, 2006/02

https://doi.org/10.1143/JPSJ.75.024710

We report the first high-field X-ray diffraction experiment using synchrotron X-rays and pulsedmagnetic fields exceeding 30 T. The lattice deformation due to a magnetic-field-induced valencetransition in YbInCu is studied. It has been found that the Bragg reflection profile at 32K changessignificantly at around 27 T due to the structural transition. In the vicinity of the transition field, the lowfield and high field phases alternate with the discontinuous change in the lattice constant. Thus, it isevident that the field-induced valence state transition is a first-order phase transition. The fielddependence of the low-field-phase Bragg peak intensity is found to be roughly scaled with themagnetization.

Application of miniature pulsed magnets to synchrotron X-ray spectroscopy and neutron diffraction

Matsuda, Yasuhiro*; Murata, Yuto*; Inami, Toshiya; Owada, Kenji; Nojiri, Hiroyuki*; Oyama, Kenji*; Kato, Naoki*; Murakami, Yoichi*; Iga, Fumitoshi*; Takabatake, Toshiro*; et al.

Journal of Physics; Conference Series, 51, p.490 - 493, 2006/00

https://doi.org/10.1088/1742-6596/51/1/111