Magnetic Properties of Rapidly Solidified (Fe1−xNix)88Zr7B4Cu1 Alloys

Abstract

In this report, soft magnetic properties of amorphous and nanocrystalline (Fe_1−xNi_x)₈₈Zr₇B₄Cu₁ alloys with x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 1.0 have been studied. The rapidly solidified ribbons have been prepared using a vacuum melt spinning technique followed by annealing for obtaining nanocrystalline phases. The Curie temperature (T_c) of amorphous phase increases with Ni content upto x = 0.6 and decreases beyond x = 0.6. The saturation magnetisation of as-spun and high-temperature (620/720 °C) annealed ribbons of (Fe_1−xNi_x)₈₈Zr₇B₄Cu₁ alloy system shows a dip at around x = 0.35 which is termed as Invar behaviour. However, Invar behaviour is not observed in 450/500 °C annealed ribbons due to the absence of fcc phase which becomes non-magnetic around x = 0.35 and is responsible for the dip in magnetisation. The coercivity of 620/750 °C annealed ribbons is high as compared to as-spun and 450/500 °C annealed ribbons due to the presence of Fe₃Zr/Ni₅Zr phases.