Normal-State Spin Dynamics and Temperature-Dependent Spin Resonance Energy in an Optimally Doped Iron Arsenide Superconductor

7 September 2009 (Mon) 14:30 – 16:00

8F large seminar room, Sengen site

Dr. Vladimir Hinkov

Max-Planck-Institute for Solid State Research

"Normal-State Spin Dynamics and Temperature-Dependent Spin Resonance Energy in an Optimally Doped Iron Arsenide Superconductor

Using inelastic neutron scattering we have studied the spin excitations in optimally doped BaFe(1.85)Co(0.15)As(2) (Tc = 25 K) over a wide range of temperatures and energies. I will contrast our results to findings in cuprates and heavy fermion superconductors, and discuss their implications to theory. In particular, we find that in contrast to cuprates, the spectrum is in good agreement with predictions of the theory of nearly antiferromagnetic metals, without complications arising from a pseudogap or competing incommensurate spin-modulated phases. This simplifies the theoretical treatment, and our data provide the foundation for the development of quantitative theories of magnetically mediated superconductivity in the iron arsenides.

Dr. Hiroyuki Yamase(山瀬博之)