Magnetism of σ-phase Fe–Mo alloys: ac magnetic susceptibility study

A series of four σ-Fe100−xMox samples was investigated with ac magnetic susceptibility measurements. An evidence was found that the ground magnetic state of the samples is constituted by a spin glass (SG) with the spin glass temperature ranging between ∼34 K for x = 45 and ∼16 K for x = 53. The SG state is heterogeneous and it can be divided into a weak-irreversibility and a strong-irreversibility domains. Its figures of merit are typical of metallic (canonical) spin glasses.