Abstract:

Sodium cobalt oxide has recently attracted a lot of attention because it is the parent compound of a superconductor.  Superficial similarities to the cuprates are striking; but on closer inspection more and more differences emerge.  In this talk, I shall present some recent experimental data from various groups, focusing particularly on the "Curie-Weiss metal" and magnetically ordered phases that occur at large doping.  I shall discuss some of the puzzling features of the data, and propose a (tentative) explanation based on an itinerant-electron starting point.