| People | Locations | Statistics |
|---|---|---|
| Naji, M. |
| |
| Motta, Antonella |
| |
| Aletan, Dirar |
| |
| Mohamed, Tarek |
| |
| Ertürk, Emre |
| |
| Taccardi, Nicola |
| |
| Kononenko, Denys |
| |
| Petrov, R. H. | Madrid |
|
| Alshaaer, Mazen | Brussels |
|
| Bih, L. |
| |
| Casati, R. |
| |
| Muller, Hermance |
| |
| Kočí, Jan | Prague |
|
| Šuljagić, Marija |
| |
| Kalteremidou, Kalliopi-Artemi | Brussels |
|
| Azam, Siraj |
| |
| Ospanova, Alyiya |
| |
| Blanpain, Bart |
| |
| Ali, M. A. |
| |
| Popa, V. |
| |
| Rančić, M. |
| |
| Ollier, Nadège |
| |
| Azevedo, Nuno Monteiro |
| |
| Landes, Michael |
| |
| Rignanese, Gian-Marco |
|
Buechner, Bernd
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (9/9 displayed)
- 2013Spatial recognition of defects and tube type in carbon nanotube field effect transistors using electrostatic force microscopycitations
- 2013Growth of all-carbon horizontally aligned single-walled carbon nanotubes nucleated from fullerene-based structurescitations
- 2012Understanding the growth of amorphous SiO2 nanofibers and crystalline binary nanoparticles produced by laser ablationcitations
- 2011The catalytic potential of high-kappa dielectrics for graphene formationcitations
- 2011Synthesis of carbon nanotubes with and without catalyst particlescitations
- 2011As-vacancies, local moments, and Pauli limiting in LaO_0.9F_0.1FeAs_(1-delta) superconductorscitations
- 2011Graphene: Piecing it Togethercitations
- 2010Enhanced pi-pi interactions between a C-60 fullerene and a buckle bend on a double-walled carbon nanotubecitations
- 2010Direct Low-Temperature Nanographene CVD Synthesis over a Dielectric Insulatorcitations
Places of action
| Organizations | Location | People |
|---|
document
As-vacancies, local moments, and Pauli limiting in LaO_0.9F_0.1FeAs_(1-delta) superconductors
Abstract
We report magnetization measurements of As-deficient LaO_0.9F_0.1FeAs_1-delta (delta about 0.06) samples with improved superconducting properties as compared with As-stoichiometric optimally doped La-1111 samples. In this As-deficient system with almost homogeneously distributed As-vacancies (AV), as suggested by the (75)As-nuclear quadrupole resonance (NQR) measurements,we observe a strong enhancement of the spin-susceptibility by a factor of 3-7. This observation is attributed to the presence of an electronically localized state around each AV, carrying a magnetic moment of about 3.2 mu_Bohr per AV or 0.8 mu_Bohr/Fe atom. From theoretical considerations we find that the formation of a local moment on neighboring iron sites of an AV sets in when the local Coulomb interaction exceeds a critical value of about 1.0 eV in the dilute limit. Its estimated value amounts to ~ 2.5 eV and implies an upper bound of ~ 2 eV for the Coulomb repulsion at Fe sites beyond the first neighbor-shell of an AV. Electronic correlations are thus moderate/weak in doped La-1111. The strongly enhanced spin susceptibility is responsible for the Pauli limiting behavior of the superconductivity that we observe in As-deficient LaO_0.9F_0.1FeAs_1-delta. In contrast, no Pauli limiting behavior is found for the optimally doped, As-stoichiometric LaO_0.9F_0.1FeAs superconductor in accord with its low spin susceptibility. ; Comment: 11 pages, 9 figures