Time and thermal stability of magnetic properties of amorphous Fe80TM3B17 alloys

We have investigated the influence of the addition of different transition metals (Fe. Co. Cr. Mn. Mo. Ni. Os. Pr. Ru. Ta. Ti. V and W) on the time-temperature stability of amorphous Fe80Tm3B1- alloys. Time stability is represented by the Magnetic After - Effect (MAE). Each element influences near neighbourhood of other atoms by its characteristic way which results in a different characteristics of the MAE spectra and its spectra of activation energies. It turned out from our measurements that samples can be divided into the three groups: The first one contains alloys with MAE similar to that of an FeB alloy, in the second there are alloys with different MAE. and in the third one there are alloys with almost no MAE. It was found that MAE can be successfully described on the basis of the micromagnetic model with activation parameters Q* = 1.3 - 1.7 eV and tau(0) = 10(-18) - 10(-13)s. Small values of the preexponential factor points our that MAE in Fe80Tm3B17 amorphous alloys is caused by the rearrangement of the mobile atom pairs within the domain walls.