Effect of germanium on the microstructure and the magnetic properties of Fe–B–Si amorphous alloys

In this work, we present a systematic study on the crystallization kinetics and the magnetic properties of melt-spun Fe80B10Si10 − xGex (x = 0.0 − 10.0) amorphous alloys. The activation energy for crystallization, determined by differential scanning calorimetry, displayed a strong dependence on the Ge content, reflecting a deleterious effect on the alloys' thermal stability and their glass forming ability with increasing Ge concentration. On the other hand, the alloys exhibited excellent soft magnetic properties, i.e., high saturation magnetization values (around 1.60 T), alongside Curie temperatures of up to 600 K. Complementary, for increasing Ge substitution, the ferromagnetic resonance spectra showed a microstructural evolution comprising at least two different magnetic phases corresponding to a majority amorphous matrix and to Fe(Si, Ge) nanocrystallites for x ≥ 7.5.

► The thermal stability and magnetic properties of melt-spun Fe80B10Si10 − xGex (x = 0 − 10) alloys were studied. ► The alloys' thermal stability and their glass forming ability decrease with Ge increasing. ► The alloys exhibit high saturation magnetization around 1.60 T alongside Curie temperatures of up to 600 K. ► Two different magnetic phases are identified using ferromagnetic resonance technique.