Spin-Glass Behaviour and Electronic Structure of LiEu2Si3

The electronic structure and properties of LiEu2Si3 are investigated, using ab initio methods and experimental techniques. All europium ions are found in a 8S7/2 configuration. The system is metallic. We found evidence of competing exchange interactions between Eu moments which may result in the onset of a spin-glass behavior below 70 K. The electronic structures of LiEu2Si3 and the isostructural (inexistent) LiSr2Si3 are compared. The ambiguous role of lithium is discussed. The fact that LiEu2Si3 and LiSr2Si3 crystallize in different structure types is justified here, considering their relative thermodynamical stability and the difference between the effective charges of europium and strontium.