Stephen J. Blundell

A handful of copper coins scattered on a triangular grid freezes into a strange order when a current is passed through them. That's roughly how tiny magnetic arrows, electron spins, behave in a crystal with the rare name Y-capellasite.

The magnetic framework of the EuMnSb2 crystal resembles scaffolding: manganese atoms form rigid vertical pillars, while europium atoms act as movable crossbars. Until now, there was no consensus on the angle at which these crossbars rest and how they rotate when a magnetic field presses on the scaffold.