Dynamic and dimensional properties of Barkhausen noise

The Barkhausen noise (BN) has been used for a long time for characterizing magnetic properties of ferromagnetic materials including non-destructive testing. Despite of that fact there is no clear understanding what is the surface layer thickness detected by BN, what are mechanisms for its dynamic behavior and how to normalize it. Here we show that results of BN measurements depends strongly on the data evaluation procedure, particularly dynamic dependence of BN. The penetration depth, classically defined as a function of conductivity and permeability, also strongly depends on other parameters as the grain size and texture.