Study by Magnetic Barkhausen Noise of a 1020 Steel and 99.9% Nickel Plate

When a low frequency external variable magnetic field is applied to a ferromagnetic material, a movement of its magnetic domains due to the realignment in the direction of the applied field occurs. This realignment produces a signal which is captured by a coil in the surface of the studied sample, as a high frequency noise (1 kHz – 1 MHz), known as magnetic Barkhausen noise (MBN). In this paper, the study of the signals obtained by the MBN technique in 1020 steel and 99.9% nickel samples is presented. The results of this technique are used to identify differences between the signals from different samples, due to the finished surface by mechanical polishing, and are compared to their respective crystalline microstructures and magnetic properties.