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

A series of four sigma-Fe(100-x)Mo(x) 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 ca. 34K for x=47 and ca. 16K 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.