Effects of magnetostatic interaction on the magnetization processes in Fe73.5Cu1Nb3Si13.5B9 nanocrystalline wires

Fe73.5Cu1Nb3Si13.5B9 amorphous wire was annealed at different temperatures (Ta=400-700 deg. C, for 30 min) that result in partial devitrification and subsequently, the quasi-saturated hysteresis loop was measured. It is found that the loops are not symmetric, exhibiting two coercive fields, Hc1 and Hc2, on descending and ascending branches, respectively. Moreover, the asymmetry degree is modified when the sample is previously magnetized under a field of 60 kA m-1. The dependence on both maximum measured field, Hm, and temperature, T, of the displaced loop has been determined. With increasing Hm, the shift Hsh=(Hc2+Hc1)/2 decreases and the coercivity Hc=(Hc2-Hc1)/2 increases, but Hsh-Hc Hc1 remains constant. Both Hsh and the magnetic polarization, μ0Mm, at maximum field decreases with elevating T. The loop of this sample also shows a remarkable time-effect. The Hm- and T-dependent Hsh is discussed considering the existence of an effective bias-field generated from the magnetostatic interaction between the nanocrystalline particles and residual soft matrix, and the time-effect could be ascribed to the dipolar interaction among the particles. (author)