Onset of magnetic ordering in heavy fermion CeNi and (Ce0.97Gd0.03)Ni

Electronic states of Ce and Ni in heavy fermion CeNi were studied from both a macro-scopic magnetization measurement and a micro-scopic way of magnetic Compton profile MCP. The behaviour of magnetization as a function of temperature resembles to that of α-Ce in the range between 4 K and 150 K and no clear magnetic ordering was observed. The maximum value of magnetization corresponded to 0.01 μB of the constituent. The MCP measurement at 20 K coincided with that of magnetization. The substitution of only 3 at% of Gd for Ce was found to cause a kind of magnetic ordering and the tentative Curie temperature was assumed to be about 2 K. The magnetic structure of the substituted material (Ce0.97Gd0.03)Ni was possible to be a ferri-magnet from the inverse susceptibility measurement.