From cuprates to manganites: spin and orbital liquids

First we analyze the peculiar magnetic response of metallic cuprates upon impurity doping. We argue that the magnetic behavior can be well understood if one assumes the spins of the CuO2 planes to form a spin liquid. The subsequent Chapters are devoted to the metallic state of manganites. Elaborating on the notion of an orbital liquid, we study the interplay of electron correlations, orbital degeneracy, and double exchange. (orig.)