Spin-glass behavior in CeCuxNi4−xMn and Ce0.9Nd0.1Ni4Mn compounds

The ferromagnetic CeNi4Mn compound has been recently studied due to its promising properties resembling half-metallic behavior. It has structure (cubic or hexagonal), which is sensitive to small changes of the stoichiometry. On the other hand, the hexagonal CeCu4Mn compound shows features typical of spin-glasses. We report on investigations of the evolution of the magnetic properties in the series CeCuxNi4−xMn. We present the measurements of the dc and ac magnetic susceptibility, the later as a function of the frequency. Besides, the magnetization relaxation has been studied. The decay of the remanent magnetization as a function of time is observed already for a small substitution of Ni with Cu or Ce with Nd. The frustration within these compounds is explained by disorder due to the statistical occupation of the 3g site in the CaCu5-type structure.