Effect of the demagnetisation factor on the Barkhausen noise signal

Abstract

In the presence of a demagnetisation factor, a splitting of the magnetic Barkhausen noise (MBN) signal distribution was observed in the form of two peaks during a slowly varying magnetisation sweep through specimens of an alloy steel. On the other hand, for closed field magnetisation, a single peak was observed at the coercivity point. The demagnetisation factor was introduced by solenoid coil magnetisation and by providing air gaps in specimens magnetised by a ‘U’-shaped yoke. The results show the importance of a standard mode of magnetisation. The splitting is explained in terms of the unimpeded growth of nucleated domains in the early period of the magnetic sweep.