Inductance of quantum-mechanical origin

An inductor is a circuit element that stores electric energy in the form of a magnetic field and consists of a coil carrying the electric current. The relation between current, magnetic field and induced voltage is described by classical electromagnetism, namely Faraday’s law of induction. Now, Tomoyuki Yokouchi and co-workers report an inductance of quantum-mechanical origin based on the emergent electric field induced by current-driven dynamics of spin helices in a magnet. The observed inductance is enhanced by nonlinearity in current and shows non-monotonous frequency dependence. It is comparable in magnitude to that of a commercial inductor, but in a volume about a million times smaller. These results might enable the realization of microscale simple-shape inductors.