Nature Physics (2026)."> a, Schematic illustration of in-situ ultrafast laser Lorentz transmission electron microscopy. b, Representative over-focus Lorentz TEM image showing a variety of topological magnetic solitons. c, Statistically stable solution of an isolated hopfion in a plate of a chiral magnet with isotropic bulk DMI and zero external field, and its simulated Lorentz TEM images. Credit: Chen et al., Nature Physics (2026). Over the past few decades, some physicists worldwide have been investigating unusual particle-like magnetic structures known as topological solitons. These structures could potentially be leveraged to develop new cutting-edge technologies, such as new magnetic memory devices and computing systems. A type of topological solitons that has proven to be difficult to realize experimentally is the hopfion. This is a three-dimensional (3D) structure comprised of closed loops of continuously swirling spin textures, which can resemble linked or knotted vortex strings.…