engleski

NMR study of the electronic properties of superconducting LaO0.9F0.1FeAs

We have performed 139La, 57Fe and 75As nuclear magnetic resonance (NMR) measurements on aligned powders of the optimally doped LaO0.9F0.1FeAs superconductor. For all three nuclei, it is found that the spin lattice relaxation rates scale with one another, with magnitudes reflecting that the FeAs layers support the electronic properties. This scaling suggests a lack of any q-space structure in the dynamical spin susceptibility, contrary to what may be expected in the presence of antiferromagnetic correlations. Rather, our results are more compatible with simple quasi- particle scattering. Furthermore, the 75As relaxation rate decreases linearly from 480 K down to the superconducting transition temperature, making pseudogap fits inadequate. The decrease of the dynamic spin susceptibility with decreasing temperature is compatible with a decrease of the density of states, rather than a change of correlations in q-space.

iron arsenide superconductors; nuclear magnetic resonance (NMR); pseudogap

Rad je prezentiran na skupu 9th International Conference on Materials and Mechanisms of Superconductivity ; Masao Ogata (ur.).