Amorphous and nanocrystalline fraction calculus for the Fe73.5Si3.5Ge10Nb3B9Cu1 alloy

We studied the relationship between the saturation magnetization (M S) of the Fe73.5Si3.5Ge10Nb3B9Cu1 alloy and its nanocrystalline structure. Amorphous ribbons obtained by the melt spinning technique were heat-treated for 1 h at different temperatures. The optimal treatment to obtain a homogeneous structure of Fe3(Si,Ge) nanocrystals with a grain size of around 10 nm embedded in an amorphous matrix involved heating at 540 C for 1 h. We calculated the magnetic contribution of the nanocrystals to the heat treated alloy using a linear model and measured the M S of the Fe73.5Si3.5Ge10Nb3B9Cu1 nanocrystalline and of an amorphous alloy of the same composition of the amorphous matrix: Fe58Si0.5Ge3.5Cu3Nb9B26. Using experimental data and theoretical calculations, we obtained the amorphous and crystalline fraction of the heat-treated ribbons