EFFECT OF THE DEMAGNETIZATION FACTOR ON THE BARKHAUSEN NOISE SIGNAL

In the presence of a demagnetisation factor, a splitting of the magnet ic Barkhausen noise (MEN) signal distribution was observed in the form of two peaks during a slowly varying magnetisation sweep through spec imens of an alloy steel. On the other hand, for closed field magnetisa tion, a single peak was observed at the coercivity point. The demagnet isation factor was introduced by solenoid coil magnetisation and by pr oviding air gaps in specimens magnetised by a 'U'-shaped yoke. The res ults show the importance of a standard mode of magnetisation. The spli tting is explained in terms of the unimpeded growth of nucleated domai ns in the early period of the magnetic sweep.