RADIOFREQUENCY INDUCED EFFECTS IN AMORPHOUS AND NANOCRYSTALLINE FE73.5CU1NB3SI13.5B9

The rf collapse and sideband effects are used to study the microstruct ure of the Fe73.5Cu1Nb3Si13.5B9 alloy in the amorphous and nanocrystal line state. Nanocrystalline grains of alpha-Fe(Si) are formed as a res ult of annealing of the amorphous alloy at 520-570 degrees C. The resu lts show that the complete rf collapse of magnetic hfs in the Mossbaue r spectra occurs only in the amorphous phase. The rf collapse is stron gly affected by the onset of the nanocrystalline phase and is suppress ed when the Fe3B and Fe2B phases are formed. Partial collapse allows u s to follow the remaining crystalline fractions during the crystalline process. The rf sidebands disappear due to the formation of nanocryst als because of the vanishing magnetostriction.