Half-magnetization plateaux in Cr spinels
  Magnetization plateaux, visible as anomalies in magnetic susceptibility at low temperatures, are one of the hallmarks of frustrated magnetism. An extremely robust half-magnetization plateau is observed in the spinel oxides CdCr2O4 and HgCr2O4, where it is accompanied by a substantial lattice distortion. We give an overview of the present state experiment for CdCr2O4 and HgCr2O4, and show how such a half-magnetization plateau arises quite naturally in a simple model of these systems, once coupling to the lattice is taken into account. 
Nic Shannon, Hiroaki Ueda, Yukitoshi Motome, Karlo Penc, Hiroyuki   Shiba and Hidenori Takagi