Kwang-Yong Choi

A layered magnet is like a stack of paper: each sheet is a thin crystalline layer, and foreign atoms can be inserted between them like bookmarks. In the material Co₁₋ₓFeₓNb₃S₆, some cobalt atoms are replaced by iron, and this substitution acts like changing the paper type in the stack. The sheets start vibrating differently, and the whole stack responds differently to a magnetic field.

In a crystal that for centuries was called 'fool's gold,' physicists have spotted genuine treasure. The compound MnTe2 with a pyrite structure has become the stage for a quantum ballet: spin waves here twist into left- and right-handed vortices, with the twist direction firmly tied to momentum.

Two dancers on one stage: one pulls the partner in one direction, the other in the opposite. In the crystal Cu2(OH)3Br, known as botallackite, copper atoms form chains where the spins (magnetic moments) of neighboring ions align either parallel, as in a ferromagnet, or antiparallel, as in an antiferromagnet.