How to create and destroy a skyrmion

In the quest for higher-density information storage, some scientists have turned their attention to magnetic skyrmions—stable nanometer-sized swirls of spin. Initially restricted to the ultracold regime (see Physics Today, April 2009, page 12), skyrmions are now routinely studied in various layered magnetic materials at room temperature. Researchers can generate and eliminate skyrmions en masse via magnetic fields (see Physics Today, April 2016, page 22). But that’s not good enough for a future skyrmion hard drive, which would have to be able to manipulate the magnetic vortices one by one.