BarFume - Magnetic Barkhausen Noise: From Fundamental Physics to Non-Destructive Testing

The structure of a ferromagnetic material can be characterized by its microstructural and magnetic features. When a ferromagnetic material is placed in an external magnetic field, its small magnetic domains start to move. This movement causes a measurable signal called Barkhausen noise (BN). BarFume aims to improve the understanding of how the microstructural features of the sample affect the domain wall movement, i.e. BN, and how this information could be used to improve the accuracy of BN-based quality control methods. In addition, novel machine learning techniques will be developed to automatically classify materials microstructure using BN as input. BarFume is an interdisciplinary project that combines materials characterization to BN measurements, micromagnetic modelling, and advanced statistical analysis. The utilization of the research results is obvious in collaboration with a key Finnish industrial partner.

Goal

to improve the understanding of how the microstructural features are manifested in the properties of the ensuing Barkhausen noise
to use this information to improve the accuracy of Barkhausen noise-based quality control methods
to use new machine learning techniques to construct an automatic classifier of materials microstructures using Barkhausen noise as input

Barfume research group — BarFume Group. Photo: Jonne Renvall, TAU.

Funding source

Partners

Stresstech Oy, Finland

Technical University of Denmark / DTU Nanolab, Denmark

Italian National Institute of Metrology Research, Italy

Related Infrastuctures

Research infrastructure

Tampere University

Tampere Microscopy Center

Research infrastructure

Tampere University

NDT laboratory

Research infrastructure

Tampere University

Materials testing and characterization

BarFume project team members

Mari Honkanen

Tampere University

Senior Scientist

Faculty of Engineering and Natural Sciences

+358408490133mari.honkanen [at] tuni.fi (mari[dot]honkanen[at]tuni[dot]fi)

Lasse Laurson

Tampere University

Professor

laskennallinen fysiikka

Faculty of Engineering and Natural Sciences

+358505455387lasse.laurson [at] tuni.fi (lasse[dot]laurson[at]tuni[dot]fi)

Suvi Santa-aho

Tampere University

Project Manager

Faculty of Engineering and Natural Sciences

+358408490145suvi.santa-aho [at] tuni.fi (suvi[dot]santa-aho[at]tuni[dot]fi)

Minnamari Vippola

Tampere University

Professor

Vice Dean for Research

Faculty of Engineering and Natural Sciences

+358408490148minnamari.vippola [at] tuni.fi (minnamari[dot]vippola[at]tuni[dot]fi)

Peer-reviewed scientific articles

Electron holography and micromagnetic simulations unveil the magnetic domain structure of steel-embedded Fe₃C carbides

Kaappa, S., Søndergaard Larsen, M., Santa-aho, S., Nulati Yesibolati, M., Honkanen, M., Speranza Mølhave, K., Vippola, M., Laurson, L. & Beleggia, M., Materials Characterization 235 (2026) 116314

Magnetic maze in steel resolved by correlative structural analysis

Santa-aho, S., Rozo Vasquez, J., Kaappa, S., Honkanen, M., Laurson, L., Strodick, S., Walter, F. & Vippola, M., Materials & Design 261 (2026) 115260

Long-term stability of laser processed reference samples for grinding burn detection with Barkhausen noise

Santa-aho, S., Sorsa, A., Olavison, J., Lundin, P., Holmberg, J., Saarinen, T. & Vippola, M., NDT & E International 155 (2025) 103441

Bearing steels with grinding burns studied by Barkhausen noise and advanced microscopy techniques – Role of carbides stability in steel performance

Santa-aho, S., Neslusan, M., Honkanen, M., Azzari, L., Zivotsky, O., Capek, J. & Vippola, M., NDT & E International 155 (2025) 103416

Magnetic domain walls interacting with dislocations in micromagnetic simulations

Kaappa, S., Santa-aho, S., Honkanen, M., Vippola, M. & Laurson, L., Communications Materials 5 (2024) 256.

Magnetic domain wall dynamics studied by in-situ Lorentz microscopy with aid of custom-made Hall-effect sensor holder

Honkanen, M., Lukinmaa, H., Kaappa, S., Santa-aho, S., Kajan, J., Savolainen, S., Azzari, L., Laurson, L., Palosaari, M. & Vippola, M., Ultramicroscopy 262 (2024) 113979.

Grinding optimization using nondestructive testing (NDT) and empirical models
Heininen, A., Santa-aho, S., Röttger, J., Julkunen, P. & Koskinen, K., Machining Science and Technology 28 (2024) 98.

Multi-instrumental approach to domain walls and their movement in ferromagnetic steels – Origin of Barkhausen noise studied by microscopy techniques

Santa-aho, S., Honkanen, M., Kaappa, S., Azzari, L., Saren, A., Ullakko, K., Laurson, L. & Vippola, M., Materials and Design 234 (2023) 112308.

Barkhausen noise from formation of 360° domain walls in disordered permalloy thin films

Kaappa, S. & Laurson, L., Physical Review Research 5 (2023) L022006.

Grinding burn classification with surface Barkhausen noise measurements
Santa-aho, S., Vippola, M., Sorsa, A. & Ruusunen, M., Research and Review Journal of Nondestructive Testing 1 (2023) 1.

Depinning Exponents of Thin Film Domain Walls Depend on Disorder Strength

Skaugen, A. & Laurson, L., Physical Review Letters 128 (2022) 097202.

Mimicking Barkhausen noise measurement by in-situ transmission electron microscopy - effect of microstructural steel features on Barkhausen noise

Honkanen, M., Santa-aho, S., Laurson, L., Eslahi, N., Foi, A. & Vippola, M., Acta Materialia 221 (2021) 117378.

Conference presentations

Linking magnetic steel structure and Barkhausen noise - Effect of carbides in industrial bearing steels

Santa-aho, S., Vippola, M., Honkanen, M. & Neslusan, M., Annual Conference of the Nordic Microscopy Society, June 2025, Bergen, Norway.

Barkhausen noise with micromagnetic simulations

Kaappa, S., Santa-aho, S., Honkanen, M., Vippola, M. & Laurson, L., International Conference on Barkhausen Noise and Micromagnetic Testing, September 2024, Tampere, Finland.

Advanced utilization of microscopy for Barkhausen noise studies

Santa-aho, S., Honkanen, M., Azzari, L., Kaappa, S., Laurson, L. & Vippola, M., International Conference on Barkhausen Noise and Micromagnetic Testing, September 2024, Tampere, Finland.

Influence of grinding burn and dissolution of carbides on MBN

Santa-aho, S., Honkanen, M., Vippola, M., Neslusan, M., Zivotsky, O. & Capek, J., International Conference on Barkhausen Noise and Micromagnetic Testing, September 2024, Tampere, Finland.

More complex evaluation of surface integrity using residual stress depth profile testing

Malec, J., Cervinka, F., Sorsa, A., Santa-aho, S. & Sandera, P., International Conference on Barkhausen Noise and Micromagnetic Testing, September 2024, Tampere, Finland.

Academic studies of Barkhausen noise at Tampere University

Lepistö, T., Santa-aho, S., Honkanen, M. & Vippola, M., International Conference on Barkhausen Noise and Micromagnetic Testing, September 2024, Tampere, Finland.

Magnetic behavior of steel studied by in-situ Lorentz microscopy, magnetic force microscopy and micromagnetic simulations

Honkanen, M., Santa-aho, S., Kaappa, S., Azzari, L., Lukinmaa, H., Kajan, J., Savolainen, S., Palosaari, M., Laurson, L. & Vippola, M., European Microscopy Congress, August 2024, Copenhagen, Denmark.

Long-time survey of laser processed calibration samples for Barkhausen noise method

Santa-aho, S., Sorsa, A. & Vippola, M., 11th European Conference on Residual Stresses, June 2024, Prague, Czech.

Grinding burn classification with surface Barkhausen noise measurements

Santa-aho, S., Vippola, M., Sorsa, A. & Ruusunen, M., 13th European Conference on Non-Destructive Testing, July 2023, Lisbon, Portugal.

Magnetic domain structure of ferromagnetic steels studied by Lorentz microscopy and magnetic force microscopy

Honkanen, M., Santa-aho, S. & Vippola, M., 73rd Annual Meeting of the Nordic Microscopy Society, June 2023, Uppsala, Sweden.

Novel utilization of microscopy and modelling to better understand Barkhausen noise signal

Santa-aho, S., Honkanen, M., Kaappa, S., Laurson, L. & Vippola, M., International Conference on Barkhausen noise and Micromagnetic Testing, September 2022, Stockholm, Sweden.

Sub-surface analysis of grinding burns with Barkhausen noise measurements
Santa-aho, S., Sorsa, A., Ruusunen, M. & Vippola, M., International Conference on Barkhausen noise and Micromagnetic Testing, September 2022, Stockholm, Sweden.

Motion of domain walls in ferromagnetic steel studied by TEM - Effect of microstructural features

Honkanen, M., Santa-aho, S., Eslahi, N., Foi, A. & Vippola, M., Annual Conference of the Nordic Microscopy Society, June 2021, webinar organized by University of Oslo.

Theses

Disorder dependence of Barkhausen noise in an elastic interface model: Insights for non-destructive testing applications

MSc Sanni Nousiainen, 2025

Micromagnetic simulation of Barkhausen noise origin in non-destructive testing applications

MSc Valtteri Haavisto, 2025

Barkhausen Noise from Reduced Micromagnetic Model of Domain Wall Motion

MSc Eetu Honkanen, 2024

Satunnaisessa väliaineessa liikkuvien elastisten rajapintojen vinoutunut korkeusjakauma (in Finnish)

BSc Tuuli Sillanpää, 2025

Magnetic dynamics in disordered cementite particles

BSc Kalle Pakarinen, 2024

(A)Symmetric roughness of driven elastic interfaces in random media

BSc Sanni Nousiainen, 2023

Others

Jäännösjännitettyjä tapahtumia vuodelta 2024

Riski, J. & Santa-aho, S., Hitsaustekniikka 6 (2024).

NDT-ratkaisut kehittyvät jatkuvasti myös energia-alalla

Santa-aho, S., Enertec - teollisuuden sähkö & energia 2 (2024) 26.

BarFume - Magnetic Barkhausen Noise: From Fundamental Physics to Non-Destructive Testing

Goal

Funding source

Partners

Related Infrastuctures

Tampere Microscopy Center

NDT laboratory

Materials testing and characterization

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Visit the Microscopy Center virtually

BarFume project team members

Mari Honkanen

Lasse Laurson

Suvi Santa-aho

Minnamari Vippola

Peer-reviewed scientific articles

Conference presentations

Theses

Others

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