A superconductor can switch the magnetic moment of a single-molecule magnet placed on top of it. This novel phenomenon, discovered by researchers in Italy, occurs because of quantum tunnelling of magnetic spins, and might be exploited in future quantum information technologies. Single-molecule magnets are paramagnetic materials that can switch their magnetization between two states – “spin up” and “spin down”, for example. At low temperatures, these molecular complexes retain their magnetic state even in the absence of a magnetic field because reversing the magnetization would require them to overcome an energy barrier. This magnetic “memory” effect could be exploited in spintronics and quantum computing applications since the spins can act as stable quantum bits, or qubits.