The influence of annealing temperature on magnetic properties of vitrovac 6030

Co-Fe-Mo-Mn-Si-B metallic glass ribbon (Vitrovac 6030) was subjected to the isothermal annealing at temperatures in the range 523-873 K so as to produ ce a series of samples with gradually coarser microstructure. For this seri es of samples a giant increase in the coercivity, exceeding three orders of magnitude, is observed. This increase is interpreted in terms of the stren gthening of the pinning effect of the nanocrystalline structure on the movi ng domain walls. It is shown that the anisotropy of tl le created crystalli tes is mainly responsible for the increase in the pinning force since the e ffective anisotropy seen by the wall becomes larger and larger with the gra dual increase in the density and size of the grown particles.