Researchers observe topological magnetic monopoles and dipoles in a ferromagnetic material

A scientific collaboration between scientists from Universidad de Oviedo and ALBA Synchrotron has achieved a detailed description of magnetic singularities and their interactions from the analysis of data acquired at MISTRAL beamline with the magnetic vector tomography technique. The results of the study, fully experimental not involving simulations and published at Communications Physics, provide a solid ground to understand fundamental knowledge about these singularities, what may have future applications on the design of magnetic devices.

Cerdanyola del Vallès, 31st March 2023 A non-saturated ferromagnetic material exhibits a non-uniform magnetization, forming a mosaic of magnetic domains with different magnetizations. The separation between these domains, domain walls, often intersect which results in exotic magnetization distributions called magnetic singularities. A particular type of magnetic singularities, Bloch points, are the focus of the study performed by researchers from Oviedo University and ALBA Synchrotron, and can be visualized in figure panels b and c.

The work, published at Communications Physics, described how the magnetization behaves around these Bloch points. At their location, the magnetization vectors cancel one another since they point oppositely (-> <- or <- ->), but around them they form complex patterns as the ones shown in figure at panels b and c, with vortex distribution.

A further description of the Bloch singularities is based on analogies with classical electrostatics. The converging and diverging magnetizations remind the electric fields of negative and positive point charges and lead to the concept of emergent magnetic field that, in complete analogy to electric field and electrical charge, allows to define a magnetic charge Q. Within this vision, Bloch points are described as magnetic monopoles of topological magnetic charges Q that create the emergent field Be.

Read more on the ALBA webiste

Image: Scientist at work on the MISTRAL beamline