Development and testing of new sensors for the study of magnetic Barkhausen noise

The Barkhausen effect is a response of a ferromagnetic material, that is its magnetic domains, to an imposed external alternating magnetic field. A sensor unit makes it possible to capture the so-called voltage signal of the magnetic Barkhausen noise that represents mapping of the individual characteristics of the material microstructure. The paper gives a comparison of a classical sensor unit having the magnetising and detecting sections separated and a compact sensor unit. The aim was to reduce the volume of the passive sensor unit and possibly increase the accuracy, sensibility and reliability of calibration curves. To this end two compact sensor units were developed. The first consists of a detection coil integrated into a gap of the magnetic yoke. A comparison was made of the results obtained with a compact sensor unit having an additional ferrite core and a detection section integrated as well in the magnetic yoke.