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Author (up) 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
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Author (up) Ale Crivillero, M.V.; Amigó, M.L.; Haberkorn, N.; Nieva, G.; Guimpel, J.
Title Microstructural control of the transport properties of β-FeSe films grown by sputtering Type Journal Article
Year 2019 Publication Journal of Applied Physics Abbreviated Journal Journal of Applied Physics
Volume 126 Issue 11 Pages 115303
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979 ISBN Medium
Area Expedition Conference
Notes doi: 10.1063/1.5094131 Approved no
Call Number BT @ gnieva @ Serial 847
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Author (up) Amigó, M.L.; Ale Crivillero, M.V.; Franco, D.G.; Badía–Majós, A.; Guimpel, J.; Campo, J.; Damay, F.; Porcher, F.; Condó, A.M.; Nieva, G.
Title Intrinsic pinning by naturally occurring correlated defects in FeSe 1− x Te x superconductors Type Journal Article
Year 2017 Publication Superconductor Science and Technology Abbreviated Journal Supercond. Sci. Technol.
Volume 30 Issue 8 Pages 085010
Keywords
Abstract We study the angular dependence of dissipation in the superconducting state of FeSe and Fe(Se 1− x Te x ) through electrical transport measurements, using crystalline intergrown materials. We reveal the key role of the inclusions of the non superconducting magnetic phase Fe 1− y (Se 1− x Te x ), growing into the Fe(Se 1− x Te x ) pure β -phase, in the development of a correlated defect structure. The matching of both atomic structures defines the growth habit of the crystalline material as well as the correlated planar defects orientation.
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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 0953-2048 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 773
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Author (up) 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
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Author (up) Amigó, M.L.; Crivillero, V.A.; Franco, D.G.; Badía-Majós, A.; Guimpel, J.; Nieva, G.
Title Vortex pinning by intrinsic correlated defects in Fe<inf>1-y</inf>Se Type Journal Article
Year 2014 Publication Journal of Physics: Conference Series Abbreviated Journal J. Phys.: Conf. Ser.
Volume 507 Issue Part 1 Pages
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Publisher Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
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Notes Cited By :1; Export Date: 14 March 2018 Approved no
Call Number BT @ jguimpel @ Serial 790
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Author (up) Amigó, M.L.; Haberkorn, N.; Pérez, P.; Suárez, S.; Nieva, G.
Title Vortex dynamics in β -FeSe single crystals: effects of proton irradiation and small inhomogeneous stress Type Journal Article
Year 2017 Publication Superconductor Science and Technology Abbreviated Journal Supercond. Sci. Technol.
Volume 30 Issue 12 Pages 125017
Keywords
Abstract We report on the critical current density J c and the vortex dynamics of pristine and 3 MeV proton irradiated (cumulative dose equal to ##IMG## [http://ej.iop.org/images/0953-2048/30/12/125017/sustaa9518ieqn1.gif] {$2\times {10}^{16}$} cm −2 ) β -FeSe single crystals. We also analyze a remarkable dependence of the superconducting critical temperature T c , J c and the flux creep rate S on the sample mounting method. Free-standing crystals present T c = 8.4(1) K, which increases to 10.5(1) K when they are fixed to the sample holder by embedding them with GE-7031 varnish. On the other hand, the irradiation has a marginal effect on T c . The pinning scenario can be ascribed to twin boundaries and random point defects. We find that the main effect of irradiation is to increase the density of random point defects, while the embedding mainly reduces the density of twin boundaries. Pristine and irradiated crystals present two outstanding features in the temperature dependence of the flux creep rate: ##IMG## [http://ej.iop.org/images/0953-2048/30/12/125017/sustaa9518ieqn2.gif] {$S(T)$} presents large values at low temperatures, which can be attributed to small pinning energies, and a plateau at intermediate temperatures, which can be associated with glassy relaxation. From Maley analysis, we observe that the characteristic glassy exponent μ changes from ∼1.7 to 1.35–1.4 after proton irradiation.
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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 0953-2048 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 770
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Author (up) Amigó, M.L.; Herrera, T.; Neñer, L.; Peralta Gavensky, L.; Turco, F.; Luzuriaga, J.
Title A quantitative experiment on the fountain effect in superfluid helium Type Journal Article
Year 2017 Publication European Journal of Physics Abbreviated Journal Eur. J. Phys.
Volume 38 Issue 5 Pages 055103
Keywords
Abstract Superfluid helium, a state of matter existing at low temperatures, shows many remarkable properties. One example is the so called fountain effect, where a heater can produce a jet of helium. This converts heat into mechanical motion; a machine with no moving parts, but working only below 2 K. Allen and Jones first demonstrated the effect in 1938, but their work was basically qualitative. We now present data of a quantitative version of the experiment. We have measured the heat supplied, the temperature and the height of the jet produced. We also develop equations, based on the two-fluid model of superfluid helium, that give a satisfactory fit to the data. The experiment has been performed by advanced undergraduate students in our home institution, and illustrates in a vivid way some of the striking properties of the superfluid state.
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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 0143-0807 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ pedrazp @ Serial 780
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