Naslov
NMR Studies of Electronic Properties of Superconducting LaO1-xFxFeAs

Autori
Paar, Dalibor ; Grafe, H. -J. ; Lang, G. ; Hammerath, F. ; Manthey, K. ; Koch, K. ; Rosner, H. ; Curro, N. J. ; Behr, G. ; Werner, J. ; Leps, N. ; Klingeler, R. ; Klauss, H. -H. ; Litterst, F. J. ; Büchner, B.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Skup
9th International Conference o Materials and Mechanisms of Superconductivity

Mjesto i datum
Tokyo, Japan, 07.09.2009. - 12.09.2009

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
NMR; iron pnictides; superconductivity

Sažetak
We have performed 139La, 57Fe, and 75As Nuclear Magnetic Resonance (NMR) measurements on aligned powders of the new LaO1-xFxFeAs superconductor for x=0 and x=0.1 at temperatures up to 480 K. For all three nuclei in the x=0.1 material, it is found that the local Knight shift increases monotonically with increasing temperature, and scales with the macroscopic susceptibility, suggesting a single magnetic degree of freedom. The spin lattice relaxation rate for all nuclei also scale with one another. This result suggests a lack of any q-space structure in the dynamical spin susceptibility that might be expected in the presence of antiferromagnetic correlations. Rather, our results are more compatible with simple quasi-particle scattering. Our measurements reveal a strong anisotropy of the spin lattice relaxation rate, which suggest that superconducting vortices contribute to the relaxation rate when the field is parallel to the c-axis but not for the perpendicular direction. In the superconducting state, we find evidence for line nodes in the superconducting gap and spin-singlet pairing.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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