Microstructure and some magnetic properties of bulk amorphous (Fe sub(0.61Co) sub(0).10Zr sub(0.025Hf) sub(0).025Ti sub(0.02W) sub(0).0 2B sub(0.20)) sub(1)00-xY sub(x (x=0, 2, 3 or 4) alloys)

Microstructure, revealed by X-ray diffraction, transmission electron microscopy and Moessbauer spectroscopy, and magnetic properties such as magnetic susceptibility, its disaccommodation, core losses and approach to magnetic saturation in bulk amorphous (Fe sub(0.61Co) sub(0).10Zr sub(0.025Hf) sub(0).025Ti sub(0.02W) sub(0).0 2B sub(0.20)) sub(1)00-xY sub(x (x=0, 2, 3 or 4) alloys in the as-cast state and after the annealing in vacuum at 720 K for 15 min. are studied. The investigated alloys are ferromagnetic at room temperature. The average hyperfine field induction decreases with Y concentration. Due to annealing out of free volumes its value increases after the heat treatment of the samples. The magnetic susceptibility and core losses point out that the best thermal stability by the amorphous (Fe) sub(0).61Co sub(0.10Zr) sub(0).025Hf sub(0.025Ti) sub(0).02W sub(0.0 2B) sub(0).20) sub(97Y) sub(3) alloy is exhibited. Moreover, from Moessbauer spectroscopy investigations it is shown that the mentioned above alloy is the most homogeneous. The atom packing density increases with Y concentration, which is proved by the magnetic susceptibility disaccommodation and approach to magnetic saturation studies.