Crystallization and magnetic behaviour of (Fe 1–x Co x ) 85.4 Zr 5.8 Nb 1 B 6.8 Cu 1 (x = 0, 0.1, 0.3, 0.5) alloys

Abstract

Nanocrystallization and low field magnetic properties (i.e. magnetic susceptibility and its disaccommodation) of the (Fe 1 - x Co x ) 8 5 . 4 Zr 5 . 8 Nb 1 B 6 . 8 Cu 1 (x = 0, 0.1, 0.3, 0.5) alloys are investigated. The crystalline phase in the nanocrystalline Fe 8 5 . 4 Zr 5 . 8 Nb 1 B 6 . 8 Cu 1 alloy consists of α-Fe grains whereas in the nanocrystalline (Fe 1 - x Co x ) 8 5 . 4 Zr 5 . 8 Nb 1 B 6 . 8 Cu 1 (x = 0.1, 0.3, 0.5) alloys α-FeCo phase is present. From Mossbauer spectroscopy studies we have found that α-FeCo phase for x = 0.3 and 0.5 is atomically ordered. The annealing of the amorphous Fe 8 5 . 4 Zr 5 . 8 Nb 1 B 6 . 8 Cu 1 sample below the crystallization temperature leads to the decrease of the hyperfine field due to the invar effect. This phenomenon has not been observed in alloys containing Co. In the isochronal disaccommodation curves of the nanocrystalline (Fe 1 - x Co x ) 8 5 . 4 Zr 5 . 8 Nb 1 B 6 . 8 Cu 1 (x = 0.3, 0.5) alloys broad maxima are present. This effect has not been observed in Fe-based nanocrystalline alloys.