Powerful rare-earth free magnet ‘evolved’ and refined by machine learning algorithm

A rare-earth free magnetic material with similar properties to the rare-earth magnets found in everything from wind turbines to computer hard drives has been discovered by US researchers using a machine learning-guided approach. The material requires further development, but the demonstration constitutes an important step in materials design.

Permanent magnets are crucial to the generation of electricity in hydropower, wind power and numerous other green energy technologies, as well as to information technologies. These devices need strong magnets with high coercivity – a well-constrained magnetic field. Making these requires a magnetic material with high magnetic anisotropy – dependence of the magnetic moment on the angle of the lattice . ‘So far the magnets with high anisotropy have contained rare earths,’ says Cai-Zhuang Wang of the US Department of Energy’s Ames Laboratory at Iowa State University. ‘Why is a very fundamental question that’s not fully understood yet.’ Regardless of the mechanism, however, demand for permanent magnets is set to grow as society moves to cut emissions by electrifying transport and industry. Magnets made from cheap elements such as iron will, therefore, be in high demand.