The retarding field model of Barkhausen noise and permeability in conventional and highly grain-oriented 3% Si-Fe polycrystals

The Barkhausen noise envelope, the permeability and the hysteresis curve in highly grain-oriented HiB-8, and in annealed and cold-worked conventional 3% Si-Fe were measured simultaneously in order to investigate the microstructural dependence of domain wall dynamics. The square and round hysteresis loops in the annealed and cold-worked specimen, respectively, are explained by the retarding field curve H_r(x). The Barkhausen signal and the permeability are represented by the sum of the fluctuating ΔH_I,i and the instantaneous averaged net field 〈H_I,i〉. The two peaks of the enve lope observed in the annealed conventional 3%Si-Fe and HiB-8 at the knees of B-H loop and the single peak in the cold-worked specimen at H_c are explained in terms of the distribution functions of the processes of domain nucleation f[ΔH_I,i(nucl)], annihilation f[ΔH_I,i(annih)] and wall displacement f[ΔH_I,i(disp)]. T he frequency spectrum of the Barkhausen pulses was measured to investigate the nature of clustering and overlapping.