Long-Time Variation of Magnetization in Concentrated Spin-Glasses

Abstract

Time variations of magnetization M(t) in reentrant spin-glass (RSG) alloys Fe₆₅(Ni_0.866Mn_0.134)₃₅, Fe₆₅(Ni_0.60Mn_0.40)₃₅ and Fe_0.70Al_0.30, together with a typical spin-glass alloy Cu_0.95Mn_0.05, have been measured under various combinations of temperature (T), magnetic field (H) and waiting time (t_w). The observed M(t) for all samples under various combinations of T, H and t_w can be traced by a newly proposed function within the time range 12<t<10⁵ s. The time variation behavior for each measurement is well represented by a characteristic time t_max which corresponds to the maximum position of the relaxation rate S(t). The characteristics of long-time variation of M(t) in the RSG materials have been discussed based on a magnetic cluster model.