Antiferromagnetic superconductors (invited)

At present a number of antiferromagnetic superconductors are known to exist. The most significant effect of the onset of antiferromagnetic order in a superconductor is a characteristic change in the temperature dependence of the upper critical field H/sub c2/(T). It indicates a weakening of the superconducting pairing due to the antiferromagnetic molecular field. We want to discuss the theory of these phenomena and show that it can explain the changes in H/sub c2/(T) without requiring fit parameters. It is shown that the pairing prescription must be modified as proposed by Baltensperger and Straessler when an antiferromagnetic molecular field is set up. The resulting decrease in the attraction of electrons forming a pair is the main effect of antiferromagnetic order on superconductivity