Fluctuation effect at the magnetic transition of ferromagnetic dense Kondo system

In order to clarify the problem of moment formation and nonmagnetic-magnetic transition in the dense Kondo system, the specific heat, the magnetic susceptibility and the magnetization have been measured for CeSi X and CeSi 2−X Ge X in the critical composition range of magnetic instability. The magnetic transition keeps to be quite sharp until we reach the very critical composition, at which we observe an extremely broadened transition. We attribute the phenomena to the large fluctuation effect in the critical composition samples.