The time decay of the saturated remanent magnetization ($M_s$) has been studied in the amorphous metallic spin glass (${\mathrm{Fe}}_{0.15}$${\mathrm{Ni}}_{0.85}$${)}_{75}$P ${}_{16}{}^{}{}_{}{}^{}\mathrm{B}_6^{}{}_{}{}^{}$${\mathrm{Al}}_3$. This relaxation, which by nature is different from the zero-field equilibrium relaxation, shows at low temperatures (T/$T_g$<0.98) a time variation accurately described by a pure power law. At temperatures in the immediate vicinity of $T_g$, the experimental time decay can be described by a power law times a stretched exponential functional form: $M_s$=$M_0$$t^{\mathrm{-}m}$ exp[-(t/${\tau }_p$${)}^{1\mathrm{-}n}$]. .AE

• Received 8 August 1986

DOI:https://doi.org/10.1103/PhysRevB.35.2075