Naslov
NMR/NQR investigation of superconductive ferropnictides

Autori
Paar, Dalibor ; Grafe, H.-J. ; Lang, G. ; Hammerath, F. ; Manthey, K. ; Wolter, A. ; Curro, N. J. ; Büchner, B.

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

Izvornik
EUROMAR 2009 - Magnetic Resonance Conference / - Gothenburg, 2009, 124-124

Skup
EUROMAR 2009 - Magnetic Resonance Conference

Mjesto i datum
Göteborg, Švedska, 05.07.2009. - 09.07.2009

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
NMR; NQR; superconductivity; ferropnictides

Sažetak
The recent discovery of superconductivity in the layered ferropnictides RO1-xFxFeAs (R=rare earth) has raised great interest within the solid state community. We have performed 139La, 57Fe, and 75As NMR and NQR measurements on the LaO1-xFxFeAs oriented powders 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. This presentation was supported by FP7-REGPOT 229390 (Solid state NMR laboratory, Zagreb).

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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