SANS study of slow dynamics in reentrant spin glass Fe 0.70 Al 0.30

Time-resolved small angle neutron scattering (SANS) measurements have been made to probe the microscopic mechanism of slow dynamics in spin glass. SANS patterns from a reentrant spin glass alloy Fe0.70Al0.30 have been traced in real time after rapidly cooling the sample to the spin-glass phase. Diffuse-scattering patterns arising from magnetic clusters continue to change for up to 20 h, as was expected from low-field susceptibility measurements. The time evolution of the magnetic clusters in the spin-glass phase was directly observed.