Mِssbauer effect study of amorphous-crystalline interface in annealed FeCuZrB

Changes in the microstructure, crystallisation behaviour and magnetic state of Fe86.5Cu1Zr6.5B6 alloy upon annealing for 1 h at 500–840 °C are examined by 57Fe Mössbauer spectrometry and X-ray diffraction. Mössbauer spectra taken in temperature range from 77 to 473 K reflect a presence of crystallites by sharp lines which are superimposed on broad features of the residual amorphous phase. The principal crystalline phase is identified as b.c.c.-Fe. An early stage of crystallisation is found already after 500 °C h−1 anneal. The total amount of crystalline phase increases with elevated temperature. Hyperfine fields of Fe atoms sitting in grain boundaries of the crystallites are affected by ordered structure of the crystallites from one side and by disordered amorphous arrangement from the other. Behaviour of this amorphous/crystalline interface zone is studied considering two independent hyperfine field distributions. One is attributed to the interface zone and the other represents amorphous remainder of the original precursor.