Most magnets — like those on a fridge door or in a compass — have two poles: north and south, or positive and negative, in a familiar arrangement called a “dipole.” But researchers are increasingly uncovering more complex forms of magnetism.

Recent advances in quantum mechanics have revealed higher orders of magnetism, including the existence of an “octupolar order” in which a pattern of particles arranged in a crystalline structure within a material behaves as if it has eight magnetic poles rather than the familiar two. However, detecting and controlling these elusive magnetic states is a significant challenge.

Now, a team of researchers led by quantum physicists at the University of Toronto has established a new method for observing quantum magnetic states using light to probe the atomic vibrations produced as electrons spin. The work is a critical first step toward harnessing multi-polar magnetism for practical technologies, including next-generation data storage and computing devices.

“We identified new signatures of a hidden type of magnetic state which cannot be detected using ordinary probes,” says Arun Paramekanti, a professor in the Department of Physics and the Centre for Quantum Information & Quantum Control in the Faculty of Arts & Science at the University of Toronto, and senior author of a study published in Physical Review Letters that describes the findings. “Our research opens up the possibility for using higher-order magnets in several applications including controllable read-write memory elements found in everyday computers.”

More information here: https://www.artsci.utoronto.ca/news/u-t-physicists-identify-octupolar-magnetism-implications-quantum-technologies

More information here: https://journals.aps.org/prl/abstract/10.1103/n11w-csdh