Frustration of magnetic interactions in heavy fermion compounds: CeNi2-xSn2 and other 1:2:2 compounds

Abstract The crystallographic structure of CeNi 2- x Sn 2 compound is reinvestigated. Two phases occur depending on preparation, the first being tetragonal, the other monoclinic with some Ni deficiency. The antiferromagnetic structure below T N =2.1 K is shown to be highly frustrated. The measured ordered moment reaches 0.90μ B at 1.5 K, 78% of the value calculated for a crystal field ionic model. This reduction is an agreement with that inferred from the analysis of specific heat data. We discuss the occurence of magnetic frustration, its incidence on long range order and on the anisotropy of the magnetic correlation length in related systems.