For thousands of years, people have been drawn to the apparent magic of magnets. Ancient Greek philosophers believed dark rocks called lodestones had souls because of their ability to move iron flakes.
Physicists now know that magnetic materials glean their power from the behavior of the atoms inside them. But magnetism still holds secrets. Researchers have recently found signs of a wholly new class of magnetism, one with characteristics of each of the two conventional kinds, ferromagnetism and antiferromagnetism.
More than 200 materials should exhibit the newfound phenomenon, according to theoretical predictions, and physicists are closing in on direct experimental evidence for it, which could lead to more efficient electronic devices. Already they have found a handful of materials that seem to exhibit this “fundamentally new type of magnetism,” says Paul McClarty, a physicist at the Léon Brillouin Laboratory. “It’s expanding our understanding of the ways that matter can work.”
Inside solid materials, atoms are surrounded by electrons that all have a property called spin, which endows each atom with its own tiny magnetic field. The total spin for each atom is represented by an arrow that can point in different directions. In ferromagnets, all the spins inside the material are aligned, resulting in a net magnetic field. In addition to sticking photos to the fridge, ferromagnets are useful because their spins can easily be flipped around by applying another magnetic field, creating distinct states that can be used as computer memory. This technique birthed the emerging technology of spintronics, in which information is encoded via electron spin rather than charge.
Physicists now know that magnetic materials glean their power from the behavior of the atoms inside them. But magnetism still holds secrets. Researchers have recently found signs of a wholly new class of magnetism, one with characteristics of each of the two conventional kinds, ferromagnetism and antiferromagnetism.
More than 200 materials should exhibit the newfound phenomenon, according to theoretical predictions, and physicists are closing in on direct experimental evidence for it, which could lead to more efficient electronic devices. Already they have found a handful of materials that seem to exhibit this “fundamentally new type of magnetism,” says Paul McClarty, a physicist at the Léon Brillouin Laboratory. “It’s expanding our understanding of the ways that matter can work.”
Inside solid materials, atoms are surrounded by electrons that all have a property called spin, which endows each atom with its own tiny magnetic field. The total spin for each atom is represented by an arrow that can point in different directions. In ferromagnets, all the spins inside the material are aligned, resulting in a net magnetic field. In addition to sticking photos to the fridge, ferromagnets are useful because their spins can easily be flipped around by applying another magnetic field, creating distinct states that can be used as computer memory. This technique birthed the emerging technology of spintronics, in which information is encoded via electron spin rather than charge.
