Exchange interaction through amorphous intergranular layers in a two-phasesystem

Amorphous melt spun ribbons of composition Fe87.2Zr7.4B4.3Cu1.1 have been a nnealed at temperatures between 713 K and 923 K, achieving different stages of the nanocrystallization process. The sample annealed at 748 K shows a l arge magnetic hardening at room temperature as well as an irregular domain pattern. Both are attributed to the presence of non-coupled crystallites. W hen cooled to 250 K, the coercivity of this sample decreases steeply as the crystallites become coupled. The samples as cast and annealed at higher te mperatures are magnetically soft and show wide regular domains. The above m entioned results as well as the thermal dependence of the coercivity are qu alitatively described in the framework of a previously proposed model that accounts for the effective anisotropy in two-phase nanocrystalline material s.