Nonequilibrium magnetic dynamics in mechanically alloyed materials - art. no. 094438

The magnetically glassy behavior of mechanically alloyed Fe61RC30Cr9 is rep orted in detail, including a static and dynamic study of the freezing proce ss, the observation of aging in a mechanically alloyed sample, Mossbauer an alysis, and annealing experiments. Despite the clear collective character o f the low-temperature change of regime, no thermodynamical spin-glass mean- field transition could be proved. On the other hand, the careful comparison of the magnetic behavior with that reported in strongly interacting fine p articles systems hinted towards the presence of that kind of particles in o ur samples. Structural considerations based on XRD, Mossbauer, and the evol ution of the ae susceptibility peaks upon annealing pointed to the existenc e of very fine Fc-rich clusters able to support a magnetic moment. confirmi ng the diagnosis extracted from the magnetic dynamics analysis. The argumen t is strengthened by the study of the effects of milling on the freezing te mperature in a second sample showing a similar behavior: Fe35Al50B15. The e xplanation can be extended naturally to previously reported mechanically al loyed, spin-glass-like samples, which hints towards the generalization of o ur interpretation.