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Ge and EuCuSi studied by soft X-ray photoemission spectroscopy川崎 郁斗; 藤森 伸一; 竹田 幸治; 山上 浩志; 伊覇 航*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
Physical Review B, 100(3), p.035111_1 - 035111_8, 2019/07
We have carried out angle-integrated photoemission spectroscopy (AIPES) and angle-resolved photoemission spectroscopy (ARPES) experiments using soft X-rays on single crystals of EuCuGe and EuCuSi grown by the Bridgman method to investigate their electronic structures. The AIPES results showed that the Eu ions in EuCuGe and EuCuSi are in a divalent state and a nearly trivalent state, respectively, in accord with the previously reported magnetic properties. The three-dimensional band structures and shapes of the Fermi surfaces of EuCuGe and EuCuSi were studied by ARPES measurements. We found that the band structures near the Fermi level and Fermi surfaces of EuCuGe and EuCuSi are very different from each other and are well reproduced by the band structure calculations based on density-functional theory for SrCuGe and YCuSi. This suggests that a charge transfer from the localized 4
states into the valence bands is responsible for the difference in the electronic states between EuCuGe and EuCuSi.
伊覇 航*; 垣花 将司*; 松田 進弥*; 本多 史憲*; 芳賀 芳範; 竹内 徹也*; 中島 美帆*; 天児 寧*; 郷地 順*; 上床 美也*; et al.
Journal of Alloys and Compounds, 788, p.361 - 366, 2019/06
Ferromagnetic ordering of EuCuP is investigated on a single crystal sample grown from tin flux. Application of hydrostatic pressure up to 8 GPa stabilizes ferromagnetic ordering, suggesting divalent Eu is stable. The Hall effect and resistivity measurements show that EuCuP is a low-carrier ferromagnetic metal with a characteristic resistivity cusp appearing at the ferromagnetic transition temperature.
Si竹内 徹也*; 屋良 朝之*; 安次富 洋介*; 伊覇 航*; 垣花 将司*; 中島 美帆*; 天児 寧*; 本多 史憲*; 本間 佳哉*; 青木 大*; et al.
Journal of the Physical Society of Japan, 87(7), p.074709_1 - 074709_14, 2018/07
被引用回数：2 パーセンタイル：29.91(Physics, Multidisciplinary)Effects of magnetic field and pressure on the Kondo-like behavior in the valence-fluctuating antiferromagnetic compound EuPtSi were studied using single-crystalline samples. Anomalous features in EuPtSi are due to valence fluctuation and/or valence change of the Eu ions at low temperatures.
(Ge
Si
) based on the doniach phase diagram伊覇 航*; 屋良 朝之*; 安次富 洋介*; 垣花 将司*; 竹内 徹也*; 本多 史憲*; 仲村 愛*; 青木 大*; 郷地 順*; 上床 美也*; et al.
Journal of the Physical Society of Japan, 87(6), p.064706_1 - 064706_14, 2018/06
被引用回数：2 パーセンタイル：29.91(Physics, Multidisciplinary)We succeeded in growing single crystals of the series of EuCu(GeSi) compounds.Physical property measurements demonstrate a maximum of the antiferromagnetic transition temperature appears at 
. Antiferromagnetism then disappears around 
followed by a heavy-fermion formation at higher concentrations. These observations follow the Doniach phase diagram as a function of 
.
GeとEuCuSiの電子状態の研究川崎 郁斗; 藤森 伸一; 竹田 幸治; 山上 浩志*; 伊覇 航*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
no journal, ,
EuCu(GeSi)はSi濃度を変化させることでEuの価数が変化し、磁気的な基底状態をもつEu
(x=0)の状態から非磁性のEu
(x=1)の状態に移り変わる。また、磁気秩序が消失するx=0.65近傍では重い電子状態が発現することが知られている。本講演では両端のEuCuGeとEuCuSiに対して実施した角度分解光電子分光測定の結果について紹介し、Siドープによって引き起こされる電子状態の変化について議論する。
