Reading depth of the magnetic Barkhausen noise. Ⅰ. One-phase semi-hard ribbons

摘要

The aim of this two-part work is to determine the effective depth from which the magnetic Barkhausen noise is detected. To achieve this, we have tested different materials for which the effect of reading depth is critical. This first part presents results of the measurements of a set of martensitic steel ribbons. The ribbons of varying thicknesses (from 10 μm up to 1 mm) have been measured in different magnetizing configurations (solenoid and yokes) ensuring homogeneous quasi-static magnetization. The Barkhausen noise signal obtained has a standard one-peak profile. The rms intensity of the Barkhausen noise signal rises up to a ribbon thickness of ～200 μm when a sample-wrapping search coil is used for detection. However, the practical industrial method of the surface-mounted bobbin coil gives a lower rise of the rms intensity in a smaller thickness range up to ～50 μm.