Science Alert December 1, 2020
Magnetic ring vortices were predicted over 20 years ago in 1998. An international team of researchers (UK, Switzerland, Ukraine, Russia) have found vortex rings inside a tiny pillar made of the magnetic material gadolinium-cobalt intermetallic compound GdCo2. They developed an X-ray nanotomography technique to image the three-dimensional magnetization structure inside a GdCo2 bulk magnet. The vortices were paired with their topological counterparts, antivortices. They also found closed magnetic loops present in vortex-antivortex pairs. After computationally analysing these structures in the context of magnetic vorticity they figured out these were doughnut-shaped ring vortices, intersected by magnetization singularities. Due to the magnetostatic interaction the vortices sat still in a static configuration, only disappearing after the GdCo2 was annealed. The observation of stable magnetic vortex rings opens possibilities for further studies of complex three-dimensional solitons in bulk magnets, enabling the development of applications based on three-dimensional magnetic structures…read more. TECHNICAL ARTICLE
A vortex-antivortex pair. The orange and green boxes indicate the regions where polarisation reverses. Credit: Donnelly et al., Nature Physics, 2020