In 1951 Shull showed the magnetic structure of the MnO crystal, which led to the discovery of antiferromagnetism (where the magnetic moments of some atoms point up and some point down). T N =122K
T N = 42 K M  T R = 10 K q = (2/3 1 0) Magnetic Structure from Neutron Scattering GdCu 2 Rotter et.al. J. Magn. Mag. Mat. 214 (2000) 281
Magnetic Diffraction using Laue Method (LADI – ILL) 4% Ga doped FeGe 2 This material undergoes a number of trans- itions and below 180K it locks into a non- harmonic spiral phase with a propagation vector of exactly 1/10. This gives rise to additional Bragg-peaks, which are shown in the second picture.