Normal state magnetism of the high Tc cuprate superconductors

Magnetic measurements of various types have played an essential role in establishing the novel normal state characteristics of high transition temperature (Tc) superconductors with Tc>23K. Among these materials, the highest Tc's (≤125 K) are exhibited by the layered cuprates. In this paper, the normal state magnetic susceptibilities of the cuprates are reviewed and interpreted in the context of magnetic neutron scattering and other magnetic measurements, using the La2-xMxCuO4-type and YBa2Cu3O6+x-type materials as prototypical examples. The evolution of the magnetism upon doping the insulating antiferromagnetic ''parent'' compounds with x=0 to form the high temperature superconductors is described. A recurrent property which differentiates these materials from conventional superconductors is the existence of strong antiferromagnetic correlations in the metallic state on the same sublattice of the structure in which the itinerant carriers reside. (orig.)