Magnetic properties and effect of pressure on the electronic state of EuCo2Ge2

Y. Ashitomi, M. Kakihana, F. Honda, A. Nakamura, D. Aoki, Y. Uwatoko, M. Nakashima, Y. Amako, T. Takeuchi, T. Kida, T. Tahara, M. Hagiwara, Y. Haga, M. Hedo, T. Nakama, Y. Ōnuki

研究成果: Article査読

4 被引用数 (Scopus)


EuCo2Ge2 with the tetragonal structure is a Eu-divalent antiferromagnet with the Néel temperature TN=23 K. The magnetic easy-axis corresponds to the [100] direction (a-axis), while the [001] direction (c-axis) is a hard-axis. The magnetization for H∥[100] indicates a metamagnetic transition at 25 kOe and saturates above 75 kOe. On the other hand, the hard-axis magnetization increases approximately linearly and saturates above 110 kOe. The magnetic phase diagram was constructed. A characteristic feature in EuCo2Ge2 is known as a valence transition under pressure, from Eu 2+δ to Eu 3−δ′(δ, δ′<1). We also clarified the valence transition by measuring the electrical resistivity under pressure. The valence transition occurs at 3 GPa, with a hysteresis, and terminates at about 4.5 GPa. Further increasing pressure, the electronic state is changed into a moderate heavy fermion state and approaches the nearly trivalent electronic state.

ジャーナルPhysica B: Condensed Matter
出版ステータスPublished - 2018 5 1

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学
  • 電子工学および電気工学


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