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

✍ Scribed by D. Paar; H.-J. Grafe; G. Lang; F. Hammerath; K. Manthey; G. Behr; J. Werner; B. Büchner

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 215 KB
• Volume: 470
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2009.10.155

✦ Synopsis

We have performed 139 La, 57 Fe and 75 As nuclear magnetic resonance (NMR) measurements on aligned powders of the optimally doped LaO 0.9 F 0.1 FeAs 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 75 As 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.