高圧力の科学と技術
Online ISSN : 1348-1940
Print ISSN : 0917-639X
ISSN-L : 0917-639X
15 巻, 1 号
- Information Technology on High Pressure Science -
選択された号の論文の8件中1~8を表示しています
高圧力科学におけるIT
解説
  • 光田 暁弘
    2005 年 15 巻 1 号 p. 44-51
    発行日: 2005年
    公開日: 2005/04/11
    ジャーナル フリー
    We have paid attention to the ground state of the high-temperature magnetic phase of YbInCu4 which exhibits a first-order valence transition at 42 K. The high-temperature phase, which shows Curie-Weiss paramagnetism of Yb3+, is stabilized down to zero temperature by the application of pressure and/or substitution of Y for Yb. We have measured magnetization of Yb0.8Y0.2InCu4 under high pressure in the low temperature ranges down to 0.6 K and could observe suppression of the valence transition and occurrence of ferromagnetism at the same time. The ferromagnetism is characterized by a low Curie temperature of 1.8 K and very small spontaneous magnetization of 0.067 μB/Yb.
  • 有馬 寛, 大高 理, 吉朝 朗
    2005 年 15 巻 1 号 p. 52-59
    発行日: 2005年
    公開日: 2005/04/11
    ジャーナル フリー
    Local structures around germanium in liquid germanate have been investigated by in-situ X-ray absorption measurements up to 9 GPa at 1000°C. Liquid germanate consisting of tetrahedrally coordinated germanium contracts with increasing pressure without significant changes in the local structure up to 2.5 GPa and then shows an abrupt fourfold-sixfold coordination change around 3 GPa. The coordination change is completed below 4 GPa and a high-density liquid consisting of octahedrally coordinated germanium is stable to 9 GPa. GeO6 octahedron in the high-density liquid is more compressible than that in solids, suggesting the possibility of a density inversion between liquid and solid at higher pressure. By considering the analogy of germanates to silicates, these results give some far-reaching implications for the evolution and dynamics of the Earth’s deep interior.
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