Each electron is a tiny magnet. In a single-atom-thick layer of iron chloride, they all align in the same direction, like dancers in a perfectly synchronized routine. Nature usually avoids such order (that's high entropy), but quantum forces compel them to comply.
Using a special microscope that "sees" the spin of each atom, scientists proved that this layer is a real magnet, switchable with a tiny voltage.
The most striking fact: chemically, it's almost rust. But while a rusty nail is useless, the single-atom layer opens the door to spintronics — electronics where information is carried not by charge but by magnetic state, promising ultra-fast and energy-efficient devices. The ideas of magnetism pioneers Heisenberg and Pauli have found an unexpected embodiment in this two-dimensional material.
Iron chloride is chemically very similar to common rust, but as a monolayer it transforms into a quantum magnet with amazing properties.