Barkhausen noise is an inductively measurable “crackling noise” signal originating from the jerky motion of magnetic domain walls interacting with various microstructural features of ferromagnetic materials subject to a slowly changing external magnetic field. The phenomenon is interesting as a statistical physics problem, and is also used as a non-destructive testing tool in various industrial applications.
In the paper published recently in Acta Materialia, one of the top journals in materials science, Barkhausen noise was studied in a novel fashion. To reveal the connection between microstructural features and Barkhausen noise, a typical Barkhausen noise measurement (by Suvi Santa-aho, Materials Characterization group) was mimicked by in-situ transmission electron microscopy (TEM, by Mari Honkanen, Tampere Microscopy Center), considering two different microstructures of steel, i.e., martensite and pearlite-ferrite. Specifically, analysing the noise properties we found that the shapes of the Barkhausen noise envelopes are different for the two microstructures considered.
This paper is an excellent starting point for our new consortium Academy Project Magnetic Barkhausen Noise: From Fundamental Physics to Non-Destructive Testing (BarFume), lead by Mari Honkanen (Tampere Microscopy Center).
The paper can be found here (open access):
M. Honkanen, S. Santa-aho, L. Laurson, N. Eslahi, A. Foi, and M. Vippola, Mimicking Barkhausen noise measurement by in-situ transmission electron microscopy – Effect of microstructural steel features on Barkhausen noise, Acta Mater. 221, 117378 (2021).
Read more from this news article: https://www.tuni.fi/en/news/industrial-quality-control-measurement-visualized-nanoscale