Antiferromagnetism

This phenomenon of magnetic moment coupling between adjacent atoms or ions occurs in materials other than those that are ferromagnetic. In one such group, this coupling results in an antiparallel alignment; the alignment of the spin moments of neighbouring atoms or ions in exactly opposite directions is termed antiferromagentism. Manganese Oxide (MnO) is one such material that displays this behavior. Manganese oxide is a ceramic material that is ionic in character, having both Mn and O ions. No net magnetic moment is associated with O ions, since there is a total cancellation of both spin and orbital moments. However, the Mn ions possesses s nrt magnetic moment that is Material predominantly of spin origin. These Mn ions are arrayed in the crystal structure such that the moments of adjacent ions are antiparallel. Obvioulsy, the opposing magnetic moments cancel one another and as a consequence, the solid as a whole possesses no net magnetic moment.