Dynamic normalization of the Barkhausen noise signal

The aim of this research is to propose a normalization principle for the Barkhausen noise response eliminating a dynamic contribution to the basic signal. To achieve this, it is suggested to reduce the rms profile (envelope) of the Barkhausen noise by the square root of the field rate of change, i.e. U rms ( H ) / dH / dt . This derived from our recent findings showing that the total rms intensity of the Barkhausen noise rises as the square root of the magnetizing frequency 〈 U rms 〉 ∝ f mag and that the rms profile of the Barkhausen noise is determined by the field rate of change U rms ( H ) ∼ dH / dt . Validity of the suggested normalization principle has been proved for various iron-based steels starting from harder steels with a high coercive field H c of several kA/m up to a soft electrical steel and a nanocrystalline ribbon with dc H c ≃ 10 - 30 A/m. At low magnetizing frequencies, the proposed normalization fully compensates the envelope differences giving a stable quasi-static peak near H c . The shape of these stabilized peaks demonstrates a strong resemblance to the differential permeability curves obtained from the concurrent measurements of the magnetic hysteresis loops.