Abstract
The relaxation phenomena in the spin-glass state of Y20(Mn1-xFex)80 amorphous alloys have been investigated. The single-spin response time τ0 estimated from the power law between the spin freezing temperatuer Tg and the response time τ increases with increasing x. The concentration dependence of τ0 is different from that of Tg, therefore, τ0 is influenced by a short-range order as well as the exchange energy. The average magnetic coupling obtained from the paramagnetic Curie temperature θp in Mn-rich regions is antiferro-magnetic, and gradually changes to ferromagnetic with increasing x. It is considered that the ferromagnetic short-range order develops with increasing x, consistent with the theoretical calculation of amorphous Fe.
