Magnetic after-effects in (Fe1-xGax)84B16 amorphous alloys

Magnetic after-effects (MAEs) are investigated for (Fe1-xGax)84B16 (X ≤ 0.06) amorphous alloys between RT and 450 0C with a minicomputer controlled automatic disaccommodation apparatus. Hopkinson maximum is found at temperatures higher than 380 0C and the Curie temperature increasing with increasing content of Ga. A relaxation spectrum of Richter type due to diffusion of B atoms is observed in temperature range below 300 0C. The spectrum for Ga-containing alloys initially presents two peaks. Thermal cyclings and annealing procedures affect the spectrum form and reduce the effect of Ga. Curve fitting of the relaxation spectrum results in a distribution of the activation energy characterized by two maximal values, 1.45 and 1.67 eV. MAEs with low activation energies gradually diminish with heating at low temperatures. The mechanism of effects of gallium and evolution of structural defects are discussed. (author)