|   | 
Details
   web
Records
Author Ale Crivillero, M.V.; Amigó, M.L.; Franco, D.G.; Badía-Majós, A.; Guimpel, J.; Nieva, G.
Title In Plane Vortex Dynamic Anisotropy in the Iron Deficient Fe_{1-y}Se Superconductor Type Journal Article
Year 2015 Publication Journal of Low Temperature Physics Abbreviated Journal J. Low Temp. Phys.
Volume 179 Issue 1-2 Pages 9-14
Keywords Iron-based superconductors; Electrical transport; Critical currents
Abstract We present electrical transport measurements in the superconducting dissipative state of crystalline iron deficient Fe 1−y Se samples. These iron deficient samples were synthesized using NaCl/KCl flux and are characterized by the presence of correlated defects. The dissipation in electrical transport experiments, when the driving current is perpendicular or parallel to the crystal planes, depends strongly on the direction of the applied magnetic field , ( H=12 T), within the sample plane. There is a dissipation modulation each 60∘ due to the presence of the correlated defects. We correlate these angular dependent features with the variation of the critical currents ( Jc ) changing the direction of H confined in the crystals planes. Jc was measured from magnetization loops at fixed temperatures and angles of H always within the basal planes.
Address
Corporate Author Thesis
Publisher Springer US Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-2291 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 708
Permanent link to this record
 

 
Author Amigó, M.L.; Ale Crivillero, M.V.; Franco, D.G.; Guimpel, J.; Nieva, G.
Title Influence of the Fe Concentration on the Superconducting Properties of Fe_{1-y}Se Type Journal Article
Year 2015 Publication Journal of Low Temperature Physics Abbreviated Journal
Volume 179 Issue 1-2 Pages 15-20
Keywords Chalcogenide; Vortex pinning; Correlated defects; Electrical transport; Fe deficiency
Abstract We present a comparative study of electrical transport properties in the normal state and in the dissipative superconducting state between pure TeX -FeSe phase and Fe deficient Fe TeX Se crystals. We discuss the influence of the intergrowth of the magnetic hexagonal phase (Fe TeX Se TeX ) in Fe deficient samples when compared to pure TeX -FeSe samples. In the superconducting state, we measured the TeX -plane electrical resistivity with magnetic field up to 16 T and the electrical resistivity as a function of the angle between the TeX axis and the applied field. The angular dependence at fixed temperature below the superconducting critical temperature, TeX , is very different for both sets of crystals. The Fe deficient samples display a vortex pinning-related feature at TeX 57 TeX off the plane while the pure TeX -FeSe phase samples show the persistence of a strong angular-dependent magnetoresistance characteristic of the normal state electronic structure.
Address
Corporate Author Thesis
Publisher Springer US Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-2291 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 712
Permanent link to this record
 

 
Author Hofer, J.A.; Haberkorn, N.
Title Flux flow velocity instability and quasiparticle relaxation time in nanocrystalline β-W thin films Type Journal Article
Year 2021 Publication Thin Solid Films Abbreviated Journal Thin Solid Films
Volume 730 Issue Pages 138690
Keywords Thin films; Electrical transport; Vortex velocities
Abstract We characterized the superconducting properties of a micropatterned 23 nm thick β-W film using electrical transport measurements in magnetic fields. The film is nanocrystalline and displays a smooth surface. The superconducting critical temperature is 4.6 K. The critical current densities display a fast drop with the magnetic field, indicating weak vortex pinning. From the analysis of the instability in the vortex motion at low magnetic fields in the flux-flow state, we observe vortex velocities up 800 m/s. An inelastic lifetime of quasiparticles around 0.6 ns is estimated at low temperatures. Together with high uniformity in thickness and simplicity in the fabrication process, the superconducting properties make β-W films promising for applications in fast single-photon detectors.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0040-6090 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 870
Permanent link to this record
 

 
Author Hofer, J.A.; Bengio, S.; Rozas, G.; Pérez, P.D.; Sirena, M.; Suárez, S.; Haberkorn, N.
Title Compositional effects on the electrical properties of extremely disordered molybdenum oxynitrides thin films Type Journal Article
Year 2020 Publication Materials Chemistry and Physics Abbreviated Journal Mater. Chem. Phys.
Volume 242 Issue Pages 122075
Keywords Molybdenum; Oxynitrides; Thin films; Sputtering; Electrical transport
Abstract Molybdenum oxynitride (MoNxOy) thin films were grown by reactive sputtering on Si (100) substrates at room temperature. The partial pressure of Ar was fixed at 90%, and the remaining 10% was adjusted with mixtures N2:O2 (varying from pure N2 to pure O2). The electrical properties of the films depend on the chemical composition. Thin films grown using mixtures up to 2% O2 have γ-Mo2N phase and display superconductivity. The superconducting critical temperature Tc reduces from ∼6.8 K to below 3.0 K as the oxygen increases. On the other hand, the films are mostly amorphous for gas mixtures above 2% O2. The electrical conductivity shows a semiconductor-like behavior well described by variable-range hopping conduction. The analysis of the optical properties reveals that the samples do not have a defined semiconductor bandgap, indicating that the high structural disorder produces electron excitation for a wide range of energies.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0254-0584 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 860
Permanent link to this record