Scientists from the RIKEN Center for Emergent Matter Science and colleagues have developed a new way to fabricate three-dimensional nanoscale devices from single-crystal materials using a focused ion beam instrument. The group used this new method to carve helical-shaped devices from a topological magnet composed of cobalt, tin, and sulfur, with a chemical formula of Co₃Sn₂S₂, and found that they behave like switchable diodes, meaning that they allow electricity to flow more easily in one direction than the other.