Field-dependent ac susceptibility of Ce(2)Fe(17)

Over part of the H-T plane, the field- and temperature-dependent ac susceptibility, χ(H,T), of Ce(2)Fe(17) is found to exhibit maxima, the amplitude of which increase with increasing field. While the appearance of such a maximum seems intuitively correct along a so-called 'S-shaped' magnetization (M) versus field (H) curve characterizing a metamagnetic/first-order phase transition, it has not been previously observed in the ac susceptibility of other systems exhibiting such transitions. In an attempt to identify the origin of this effect, detailed magnetization data, M(H,T), are used to reconstruct a phase diagram for this system-specifically by using the derivatives [Formula: see text] and [Formula: see text]-as detailed recently by Janssen and co-workers. This behaviour is then shown to occur on crossing the boundary from a ferromagnetic into a spin flop (SFI) phase in Ce(2)Fe(17). As a corollary, this previously atypical behaviour of χ(H,T) may be a defining characteristic of such transitions; specifically, it may reflect the possibly unique combination of ferromagnetic and antiferromagnetic interactions that are present in this system.