Talk by Christof Niedermayer, Paul Scherrer Institute, Switzerland
Laboratory for Neutron Scattering, Paul Scherrer Institute, CH 5232 Villigen, Switzerland
Coexistence of magnetism and superconductivity in underdoped Ba(Fe1-xCox)2As2
The discovery of superconductivity in iron based materials has renewed interest in the relationship between magnetism and superconductivity. The doping dependent phase diagram shows strong similarities to the generic phase diagram of the cuprate high temperature superconductors. In both systems superconductivity emerges in close proximity to an antiferromagnetic or spin-density-wave ordered state. The combined results of neutron scattering, muon spin rotation and optical conductivity measurements support our claim that bulk magnetism and superconductivity coexist and compete on a nanometer length scale in underdoped Ba(Fe1-xCox)2As2. These observations suggest that the magnetic and superconducting orders are intimately related and that antiferromagnetic spin fluctuations may play an important role in the pairing mechanism of these materials.