Regensburg 2025 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 15: Poster I

MA 15.25: Poster

Dienstag, 18. März 2025, 10:00–12:30, P1

Magnetization fluctuations probed via the anomalous Hall effect — •Nadine Nabben¹, Giacomo Sala², Ulrich Nowak¹, Matthias Krüger³, and Sebastian T. B. Goennenwein¹ — ¹Universität Konstanz — ²ETH Zürich — ³Universität Göttingen

Fluctuation phenomena inherently limit the precision of physical measurements, making it essential to understand the underlying mechanisms for improving measurement accuracy. In particular, analyzing magnetic fluctuations provides valuable insights into magnetization behavior and domain wall dynamics. We employ the anomalous Hall effect to electrically investigate low-frequency magnetization fluctuations in thin ferromagnetic layer stacks with perpendicular magnetic anisotropy. By examining the anomalous Hall effect noise at different points in the hysteresis loop, we probe the distinct types of magnetic noise associated with different magnetization states. Our results show that Barkhausen noise, exhibiting a characteristic 1/f² frequency dependence, dominates as long as magnetic relaxation processes occur. In contrast, quasi-stationary magnetization fluctuations generate noise that obeys a 1/f frequency dependence. We discuss how these findings offer new perspectives on magnetic fluctuation mechanisms and their implications for both fundamental understanding and technical applications.

Keywords: magnetization fluctuations; noise; anomalous Hall effect