A crystal without inversion symmetry is like a room where one wall is mirrored and the other is frosted: the reflection doesn't match the original. Such materials often behave unusually because electrons feel the lattice distortion. In the compound of europium with iridium, indium, and germanium — EuIr4In2Ge4—this distortion is especially pronounced.
When cooled to 2.5 K (colder than the surface of Pluto), magnetic order emerges in the crystal. Neutrons, like tiny probes, sense the arrangement of atomic magnetic moments. It turns out that the europium moments align into a simple antiferromagnetic structure: neighboring atoms point in opposite directions, like rows of arrows alternately pointing up and down.
The simplicity of the magnetic structure in such an asymmetric crystal is an important result. It helps understand how lattice distortion affects magnetism and could be useful for designing new materials for spintronics — electronics that exploits not only the electron's charge but also its spin.
The temperature of 2.5 K is just two and a half degrees above absolute zero. At such temperatures, even helium becomes superfluid and can flow up the walls of a container.