Coexistence of Intermediate Valence Ce and Ce³⁺ in the Ce₂Sn₅ Compound

Abstract

A large number of intermetallic compounds are reported to exist in the Ce-Sn diagram¹. They range from the more dilute Ce compound CeSn₃ to the richest one, Ce₃Sn. Among these compounds, CeSn₃, which crystallizes in the cubic AuCu₃ structure, presents a well established intermediate valence state : a high electronic specific heat constant ^2,3, a large thermal expansion a very weak magnetic susceptibility, with a broad maximum around 150 K^5,6,7, are the main evidences of such a property. Moreover, it has been shown recently⁸ that the large increase of the susceptibility at low temperature is due partly to the pure CeSn₃ phase but also partly to some magnetic defects which are structurally connected with the neighboring phases, mainly Ce₂Sn₅.