竹内 徹也*; 芳賀 芳範; 谷口 年史*; 伊覇 航*; 安次富 洋介*; 屋良 朝之*; 木田 孝則*; 田原 大夢*; 萩原 政幸*; 中島 美帆*; et al.
Journal of the Physical Society of Japan, 89(3), p.034705_1 - 034705_15, 2020/03
Single crystals of EuCuSi have been grown by the flux method and Bridgman method. The Eu ions of the Bridgman-grown crystal are nearly trivalent and fluctuate depending on the temperature. On the other hand, the Eu ions of flux-grown sample are divalent and thermally stable and show spin-glass behavior at low temperatures. Crystallographic analyses identified random replacement of Cu sites by Si only for the flux-grown samples. Such structural randomness leads to spin-glass features.
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
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.
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
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 .
仲村 愛*; 平仲 裕一*; 辺土 正人*; 仲間 隆男*; 立津 慶幸*; 眞榮平 孝裕*; 三浦 泰直*; 森 晶宣*; 堤 泰樹*; 広瀬 雄介*; et al.
Journal of the Physical Society of Japan, 82(12), p.124708_1 - 124708_6, 2013/12
Fermi surfaces and magnetic properties of an antiferromagnet EuBi were investigated on a flux-grown single crystal. A critical magnetic field of 225 kOe where the magnetic moments are forced to align ferromagnetically was well explained by the magnetic exchange interaction based on a two-sublattice model. The Fermi surface characteristics are in agreement with the theoretical prediction indicating a fully magnetic divalent state in Eu atoms.
仲村 愛*; 平仲 裕一*; 辺土 正人*; 仲間 隆男*; 三浦 泰直*; 堤 泰樹*; 森 晶宣*; 石田 一裕*; 三田村 勝哉*; 広瀬 雄介*; et al.
Journal of the Physical Society of Japan, 82(10), p.104703_1 - 104703_10, 2013/10
High quality single crystals of EuGa have been grown from Ga flux. Electrical resistivity, magnetic susceptibility, high-field magnetization, specific heat, thermoelectric power and de Haas-van Alphen effect were investigated. Antiferromagnetic transition due to divalent Eu atoms were observed at 16.5 K. A charge density wave transition was also found under high pressure accompanied by a Fermi surface reconstruction. These observations were fully accounted for by the Fermi surface topology and corresponding band calculations.
池田 修悟*; 酒井 宏典; 立岩 尚之; 松田 達磨; 青木 大*; 本間 佳哉*; 山本 悦嗣; 中村 彰夫; 塩川 佳伸*; 太田 有基*; et al.
Journal of the Physical Society of Japan, 78(11), p.114704_1 - 114704_10, 2009/11
We studied the magnetic properties of a paramagnet -US with the orthorhombic crystal structure by measuring the magnetization, magnetic susceptibility, specific heat and electrical resistivity under magnetic field and pressure. The 5-crystalline electric field (CEF) scheme was determined from the experimental results The insulating resistivity is drastically changed to a metallic one under high pressure 8 GPa similar to that of the semimetallic Ising-type ferromagnet UTeS with the Curie temperature =87 K. From these experimental results, it was concluded that -US is in the vicinity of the ferromagnetic ordering at ambient pressure. The anomalous magnetization was analyzed on the basis of the ferromagnetic cluster and discussed from a viewpoint of the magnetic polaron.