Pressure-Induced Valence Transition in Antiferromagnet EuRh2Si2

• Published in: Journal of the Physical Society of Japan 2012-02, Vol.81 (2), p.023709-023709-4
• Main Authors: Mitsuda, Akihiro, Hamano, Suguru, Araoka, Nobutaka, Yayama, Hideki, Wada, Hirofumi
• Format: Article
• Language: English
• ISSN: 0031-9015; 1347-4073
• DOI: 10.1143/JPSJ.81.023709

Considering the unique properties of EuRh 2 Si 2 from the viewpoint of the Eu valence, we have examined its physical properties under external pressure. At ambient pressure, EuRh 2 Si 2 is an antiferromagnet with a Néel temperature $T_{\text{N}}$ of 25 K, and the Eu ion is in the divalent state. The application of pressure up to 0.84 GPa slightly shifts $T_{\text{N}}$ toward higher values. Under pressures higher than 1.00 GPa, an abrupt first-order valence transition emerges simultaneously with the disappearance of antiferromagnetism. For $P=1.17$ GPa, the valence change associated with valence transition is roughly estimated to be ${\sim}0.19$ from the thermal expansion anomaly. The valence transition temperature $T_{\text{v}}$ increases rapidly with increasing pressure. The temperature--pressure phase diagram of EuRh 2 Si 2 is very similar to those of the other systems showing pressure-induced valence transition.