The magnets in this crystal behave like guests at a party where everyone wants the same chair. No one can settle down for good, and from this chaos, a special state emerges. In it, spin momentum (what makes an electron a tiny magnet) manages to travel 480 micrometers. For comparison, a human hair is about 80 micrometers thick, so the spin covers six such thicknesses in a row.

In ordered magnets, spins usually scatter quickly, like a whisper in a noisy room. Here, in gadolinium gallium garnet, the magnetic moments of gadolinium atoms don't align into a strict order but constantly fluctuate. Computer simulations showed that this state lacks the usual magnetization waves, magnons, but instead has strong correlations between neighboring spins. They pass the excitation along a chain like a relay baton, without dropping it along the way.

The discovery offers a simple electrical way to peek into entangled magnetic states. Moreover, frustrated magnets, materials where spins can't find a common order, could become excellent conduits for spin signals in future devices that don't require conventional electric current.