来源：ACS Publications
Mixed valency in compounds containing rare-earth elements can lead to intriguing properties, such as complex magnetism, unique charge transport, and superconductivity. Zintl A14MPn11 (14–1–11) compounds with rare-earth elements exhibit mixed or intermediate valence at the A cation sites, which affects their magnetic and transport properties. In this study, we report on the valence state of Eu cations and the magnetic properties of 14–1–11 Zintl arsenides, Eu14MAs11 (M = Mg, Zn, Cd). 151Eu Mössbauer spectroscopic analysis indicates the presence of intrinsic Eu2+ and Eu3+ cations in Eu14MgAs11 and Eu14CdAs11. In contrast, Eu14ZnAs11 shows the presence of Eu3+ cations that can be identified as an impurity. Mixed valence in Eu14MgAs11 and Eu14CdAs11 significantly affects their transport properties, resulting in lower conductivity than the Zn compound. The zero-field-cooled (ZFC) and field-cooled (FC) magnetic susceptibilities of Eu14MAs11 (M = Mg, Zn, Cd) exhibit paramagnetic behavior at high temperatures. While Eu14MgAs11 exhibits antiferromagnetic ordering at low temperatures, the ZFC and FC magnetic susceptibilities of Eu14ZnAs11 and Eu14CdAs11 diverge at low temperatures, indicating complex magnetic ordering. This work underscores how mixed valency in rare-earth-element compounds can lead to significant differences in their magnetic and transport properties.