Barkhausen Imaging: A magneto-optical approach to mapping the pinning landscape in soft ferromagnetic films

J. Trimble, J. Berezovsky

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

We demonstrate a magneto-optical microscopy technique to create two-dimensional images of the pinning behavior of a vortex state as it is translated through a soft ferromagnetic film. The resulting information yields a map of how defects and inhomogeneities in the material serve to trap high-energy-density magnetization configurations such as vortex cores or domain walls. We raster scan a vortex core within a thin permalloy disk using in-plane magnetic fields, and monitor the vortex displacement using the magneto-optical Kerr effect. The differential nature of the measurement yields spatial resolution ≈5 nm, much less than the diffraction limit, and minimum resolvable pinning energy ≈0.4 eV. The technique produces two images, one displaying the pinning-induced vortex displacement relative to the expected free motion, and the other displaying hysteretic vortex displacement between the trace and re-trace. We demonstrate the technique on two samples, extract quantitative statistics about the pinning landscape, and compare to simulated results with a pinning landscape derived from the measured surface topography of the samples.

Original languageEnglish
Article number167585
JournalJournal of Magnetism and Magnetic Materials
Volume523
DOIs
StatePublished - Apr 1 2021
Externally publishedYes

Keywords

  • Magneto-optical Kerr effect
  • Pinning
  • Vortices

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