Magnetic metamaterials: from invisibility cloaks to magnetic wormholes
Controlling magnetic fields is essential in our society. Magnetic technology has become a key part of our lives, from magnetic memories in computers to motors and energy generators, or medical techniques. Traditionally, magnetic fields are being shaped by employing magnetic materials (e. g. soft ferromagnets in transformer cores). In recent years, a new player has emerged to enlarge the family of materials to control magnetic fields: magnetic metamaterials.
With the help of aesthetic theories such as transformation optics - the possibility of manipulating the geometry of space itself-, several novel devices for controlling magnetic fields have been introduced. In this talk we present some of these new devices. They include magnetic cloaks that render any object magnetically invisible, concentrators of magnetic energy in space -even at a distance-, magnetic hoses that transfer static fields to long distances, the equivalent of gravitational wormholes for magnetic fields, and an illusion device that transforms the response of a magnetic material as it was a different one (e. g. a ferromagnet into a superconductor). Far from being only theoretical proposals, we discuss how magnetic metamaterials ideas have not only being experimentally demonstrated but they are already starting to be used in actual technological applications