Kinetics of magnetic annealing in amorphous Fe5Co75Si4B16

Kinetics of magnetic annealing in amorphous Fe5Co75Si4B16 were studied through the change in anisotropy field. Preliminary experiments on as-cast specimens revealed the irreversible and reversible processes. The reversible portions of isothermal kinetic data were well fitted to (Hk−H∞k)/(H0k−H∞k)=B−m log t where m=−0.6+1.4×10−3 T. The analyses of a single time of relaxation with first or second order were evidently unsuccessful. Although further analyses based on broad distributions of relaxation times, box or Gaussian type, give log t dependence in kinetics both distributions do not explain the linear temperature dependence (not proportional to temperature as expected from broad distribuion analyses) in the coefficient m of log t. The similar behaviors found in other alloys are also referred and discussed.