Bulk and Local Magnetic Properties of Iron-Based Oxypnictide Superconductor SmFeAsO1-xFx

Comparative high-field magnetotransport of the oxypnictide superconductors RFeAsO1−xFx (R=La, Nd) and SmFeAsO1−

We compare magnetotransport of the three iron-arsenide-based compounds ReFeAsO Re=La, Sm, Nd in very high DC and pulsed magnetic fields up to 45 and 54 T, respectively. Each sample studied exhibits a superconducting transition temperature near the maximum reported to date for that particular compound. While high magnetic fields do not suppress the superconducting state appreciably, the resistiv...

Neutron irradiation of SmFeAsO1−xFx

SmFeAsO1−xFx was irradiated in a fission reactor by a fast (E > 0.1 MeV) neutron fluence of 4 × 1021 m−2. The introduced defects increased the normal state resistivity due to a reduction in the mean free path of the charge carriers. This leads to an enhancement of the upper critical field at low temperatures. The critical current density within the grains, Jc, increases upon irradiation. The se...

Local structural investigation of SmFeAsO1−xFx high temperature superconductors

A strong revitalization of the field of high temperature superconductivity (HTSC) has been induced recently by the discovery of TC around 26 K in F-doped LaFeAsO iron pnictides. Starting from this discovery, a huge amount of experimental data have been accumulated. This important corpus of results will allow the development of suitable theoretical models aimed at describing the basic electronic...

Coexistence of magnetic fluctuations and superconductivity in the pnictide high temperature superconductor SmFeAsO1-xFx measured by muon spin rotation.

Muon spin rotation experiments were performed on the pnictide high temperature superconductor SmFeAsO1-xFx with x=0.18 and 0.3. We observed an unusual enhancement of slow spin fluctuations in the vicinity of the superconducting transition which suggests that the spin fluctuations contribute to the formation of an unconventional superconducting state. An estimate of the in-plane penetration dept...

Magnetic Order versus Superconductivity in the Iron - based La ( O 1 - xFx ) FeAs Systems