NUKLEONIKA 2007, 52(Supplement 1):S37-S41
Jan Świerczek1, Józef Lelątko2
1 Institute of Physics, Częstochowa University of Technology,
19 Armii Krajowej Ave., 42-200 Częstochowa, Poland
2 Institute of Materials Science,
University of Silesia, 12 Bankowa Str., 40-007 Katowice, Poland
Transmission Mössbauer spectra and high-resolution electron microscopy investigations for amorphous
Fe90Zr7B3 alloy in the as-quenched state and after annealing in
vacuum at temperatures 673, 723 and 743 K have been performed. In the as-quenched state the
microstructure reveals the presence of medium range order BCC- or FCC-like structure regions 1-3 nm
in size which grow during annealing at 673 K being the nuclei of grains of
a-Fe phase. After annealing at 723 K for 1 h, the grains 16 nm in diameter
and with the average distance of 110 nm between them are embedded in the paramagnetic amorphous matrix.
This distance is large enough to prevent magnetic interaction between the grains, and superparamagnetic
behavior is observed. After longer annealing at 723 K and at 743 K, the Mössbauer spectra show a
crystalline component of the a-Fe phase with the inhomogeneous amorphous
matrix consisting of para- and ferromagnetic phases. The hyperfine induction of the crystalline phase
slightly increases with time and annealing temperature which is ascribed to the faster diffusion
of atoms.