We succeeded in growing single crystals of Eu2Ni3Ge5 and EuRhSi3 by the In-flux method, and measured the electrical resistivity under pressures. Both compounds are Eu-divalent antiferromagnets with the Néel temperatures TN = 18.6 and 47.7 K, respectively. With increasing pressure, the resistivity in Eu2Ni3Ge5 indicates a clear kink at Tv = 220K under 8.0 GPa, for example, which corresponds to a valence transition. The valence of Eu ions deviates from divalence toward trivalence. Correspondingly, antiferromagnetic ordering disappears completely. The low-temperature resistivity is, surprisingly, very similar to the resistivity of a well-known heavy fermion superconductor CeCu2Si2, possessing a two-peak-structure based on the Kondo effect. In fact, the A value of the resistivity ρ = ρ0 + AT2 in the Fermi liquid relation becomes large, A = 0.3 μΩ·cm=K2 at 8.0 GPa. The similar characteristic features are observed in another compound EuRhSi3.
ASJC Scopus subject areas
- Physics and Astronomy(all)