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Author (up) Aragón Sánchez, J.; Cortés Maldonado, R.; Cejas Bolecek, N.R.; Rumi, G.; Pedrazzini, P.; Dolz, M.I.; Nieva, G.; Beek, C.J. van der; Konczykowski, M.; Dewhurst, C.D.; Cubitt, R.; Kolton, A.B.; Pautrat, A.; Fasano, Y. url  openurl
  Title Unveiling the vortex glass phase in the surface and volume of a type-II superconductor Type Journal Article
  Year 2019 Publication Communications Physics Abbreviated Journal Commun. Phys.  
  Volume 2 Issue 1 Pages 143  
  Keywords  
  Abstract Order-disorder transitions between glassy phases are common in nature and yet a comprehensive survey on the entailed structural changes is challenging since the constituents are in the micro-scale. Vortex matter in type-II superconductors is a model system where some of these experimental challenges can be tackled. Samples with point disorder present a glassy transition on increasing the density of vortices. A glassy yet quasi-crystalline phase, the Bragg glass, nucleates at low densities. The vortex glass stable at high densities is expected to be disordered, however its detailed structural properties remained experimentally elusive. Here we show that the vortex glass has large crystallites with in-plane positional displacements growing algebraically and short-range orientational order. Furthermore, the vortex glass has a finite and almost constant correlation length along the direction of vortices, in sharp contrast with strong entanglement. These results are important for the understanding of disorder-driven phase transitions in glassy condensed matter.  
  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 2399-3650 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Aragón Sánchez2019 Serial 843  
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Author (up) Aragón Sánchez, J.; Cortés Maldonado, R.; Dolz, M.I.; CejasBolecek, N.R.; van der Beek, C.J.; Konczykowski, M.; Fasano, Y. url  openurl
  Title Direct visualization of local interaction forces in Bi2Sr2CaCu2O8+δ vortex matter Type Journal Article
  Year 2019 Publication Materials Today: Proceedings Abbreviated Journal XXIII Latin American Symposium on Solid State Physics (SLAFES XXIII), San Carlos de Bariloche, Argen  
  Volume 14 Issue Pages 34-37  
  Keywords Vortex matter; Pinning forces; Layered superconductors  
  Abstract We study the local vortex-vortex interaction force fi of the structure frozen during a field-cooling process in an electron-irradiated Bi2Sr2CaCu2O8+δ sample. We compute this magnitude from snapshots of the vortex structure obtained via magnetic decoration experiments at various fields H in the same sample. Since the observed structures correspond to the equilibrium ones frozen at T∼Tirr(H)[1], at this temperature the local modulus of fi roughly equals the local pinning force at the decorated surface of the sample. We estimate the most probable local pinning force from the mode value of the fi(r)distribution, fpm. We found that fpm grows algebraically with H and in electron-irradiated samples is 50-20% smaller than for samples with columnar defects.  
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  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2214-7853 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 852  
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Author (up) Belussi, C.H.; Berisso, M.G.; Fasano, Y. doi  openurl
  Title Note: Single-polarity high-voltage amplifier to drive coarse-approach slip-stick piezoelectric motors Type Journal Article
  Year 2013 Publication Review of Scientific Instruments Abbreviated Journal Rev. Sci. Instrum.  
  Volume 84 Issue 5 Pages 056104-3  
  Keywords amplifiers; Mosfet; piezoelectric motors; scanning probe microscopy  
  Abstract Scanning probe microscopies typically rely on coarse-approach slip-stick piezoelectric motors that work by exciting piezoelectric stacks with sawtooth signals of hundreds of V and some kHz. For this application, we introduce a single-polarity high-voltage amplifier based on discrete MOSFET-technology components with improved output current desirable for low-temperature actuation. The amplifier has an output signal of 600 V, 100 mA output current, noise level below 2 μV/math, 4 kHz high-voltage bandwidth, 2 V/μs slew-rate, and rise and fall times of 80 μs (when loaded with 30 nF). The circuit was successfully applied to drive a home-made scanning tunnelling microscope.  
  Address  
  Corporate Author Thesis  
  Publisher Aip Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ berisso @ Serial 656  
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Author (up) Bolecek, N.R.C.; Dolz, M.I.; Pastoriza, H.; Konczykowski, M.; van der Beek, C.J.; Kolton, A.B.; Fasano, Y. url  doi
openurl 
  Title Excess of topological defects induced by confinement in vortex nanocrystals Type Journal Article
  Year 2017 Publication Physical Review B Abbreviated Journal PRB  
  Volume 96 Issue 2 Pages 024507  
  Keywords  
  Abstract We directly image individual vortex positions in nanocrystals in order to unveil the structural property that contributes to the depletion of the entropy jump entailed at the first-order transition. On reducing the nanocrystal size, the density of topological defects increases near the edges over a characteristic length. Within this “healing-length” distance from the sample edge, vortex rows tend to bend, while towards the center of the sample, the positional order of the vortex structure is what is expected for the Bragg-glass phase. This suggests that the healing length may be a key quantity to model confinement effects in the first-order transition of extremely layered vortex nanocrystals.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ 10.1103/PhysRevB.96.024507 Serial 762  
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Author (up) Cejas Bolecek, N.R.; Kolton, A.B.; Konczykowski, M.; Pastoriza, H.; Dominguez, D.; Fasano, Y. url  doi
openurl 
  Title Vortex matter freezing in Bi2Sr2CaCu28 samples with a very dense distribution of columnar defects Type Journal Article
  Year 2016 Publication Physical Review B Abbreviated Journal Phys. Rev. B  
  Volume 93 Issue 5 Pages 054505  
  Keywords  
  Abstract We show that the dynamical freezing of vortex structures nucleated at diluted densities in Bi2Sr2CaCu2O8 samples with a dense distribution of columnar defects, B∼10−2BΦ with BΦ=5kG, results in configurations with liquidlike correlations. We propose a freezing model considering a relaxation dynamics dominated by double-kink excitations driven by the local stresses obtained directly from experimental images. With this model we estimate the relaxation barrier and the freezing temperature. We argue that the low-field frozen vortex structures nucleated in a dense distribution of columnar defects thus correspond to an out-of-equilibrium nonentangled liquid with strongly reduced mobility rather than to a snapshot of a metastable state with divergent activation barriers as, for instance, expected for the Bose-glass phase at equilibrium.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ 10.1103/PhysRevB.93.054505 Serial 738  
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Author (up) Cejas Bolecek, N.R.; Dolz, M.I.; Kolton, A.; Pastoriza, H.; Beek, C.Jvander; Konczykowski, M.; Menghini, M.; Nieva, G.; Fasano, Y. doi  openurl
  Title Geometrical Confinement Effects in Layered Mesoscopic Vortex Matter Type Journal Article
  Year 2015 Publication Journal of Low Temperature Physics Abbreviated Journal J. Low Temp. Phys.  
  Volume 179 Issue 1-2 Pages 35-41  
  Keywords Vortex matter; Mesoscopic physics; Layered superconductors  
  Abstract We study the geometrical confinement effect in Bi 2 Sr 2 CaCu 2 O 8+δ mesoscopic vortex matter with edge-to-surface ratio of 7–12 %. Samples have in-plane square and circular edges, 30 μ m widths, and ∼ 2 μ m thickness. Direct vortex imaging reveals the compact planes of the structure align with the sample edge by introducing topological defects. The defect density is larger for circular than for square edges. Molecular dynamics simulations suggest that this density is not an out-of-equilibrium property but rather determined by the geometrical confinement.  
  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 711  
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Author (up) Cruz, F. de la; Fasano, Y.; Seta, M.D.; Menghini, M.; Pastoriza, H. openurl 
  Title Plastic and Elastic Symmetry Transformations Induced in the Vortex Lattice of Anisotropic and Layered Superconductors Type Journal Article
  Year 2004 Publication Journal of Low Temperature Physics Abbreviated Journal  
  Volume 135 Issue Pages 99-110  
  Keywords  
  Abstract We make a comparative analysis of the response of the three-dimensional vortex lattice in Bi$2$Sr$2$CaCu$8$ and NbSe$2$ to the presence of square arrays of pinning sites localized at one extremity of the vortex crystals. The absence of the hexagonal to square symmetry transformation and the induction of a distorted hexagonal symmetry in the vortex lattice of NbSe$2$ contrast to the observed symmetry change in Bi$2$Sr$2$CaCu$8$. The dissimilar response in both cases is explained taking into account the vortex structure solidification mechanisms in both materials: The plastic response in the case of the layered material Bi$2$Sr$2$CaCu$8$ is suggested to be a result of the simultaneity of solidification and coupling of bidimensional pancake vortices whereas a viscous solidification is the responsible for the three-dimensional elastic response in NbSe$_2$.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ delacruz04 Serial 15  
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Author (up) DemirdiÅŸ, S.; van der Beek, C.J.; Fasano, Y.; Cejas Bolecek, N.R.; Pastoriza, H.; Colson, D.; Rullier-Albenque, F. url  doi
openurl 
  Title Strong pinning and vortex energy distributions in single-crystalline Ba(Fe{1−x}Co{x}){2}As{2} Type Journal Article
  Year 2011 Publication Physical Review B Abbreviated Journal PRB  
  Volume 84 Issue 9 Pages 094517  
  Keywords  
  Abstract The interrelation between heterogeneity and flux pinning is studied in Ba(Fe1−xCox )2As2 single crystals with widely varying Co content x.Magnetic Bitter decoration of the superconducting vortex ensemble in crystals with x = 0.075 and x = 0.1 reveals highly disordered vortex structures. The width of the Meissner belt bserved at the edges of the crystals, and above the surface steps formed by leaving, as well as the width of the intervortex distance distribution, indicate that the observed vortex ensemble is established at a temperature just below the critical temperature Tc. The vortex interaction energy and pinning force distributions extracted from the images strongly suggest that the vortex lattice disorder is attributable to strong pinning due to spatial fluctuations of Tc and of the superfluid density. Correlating the results with the critical current density ields a typical length scale of the relevant disorder of 40–60 nm.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ Serial 605  
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Author (up) Dolz, M. I.; Fasano, Y.; Cejas Bolecek, N. R.; Pastoriza, H.; Mosser, V.; Li, M.; Konczykowski, M. url  doi
openurl 
  Title Size-Induced Depression of First-Order Transition Lines and Entropy Jump in Extremely Layered Nanocrystalline Vortex Matter Type Journal Article
  Year 2015 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 115 Issue 13 Pages 137003  
  Keywords  
  Abstract We detect the persistence of the solidification and order-disorder first-order transition lines in the phase diagram of nanocrystalline Bi2Sr2CaCu2O8 vortex matter down to a system size of less than one hundred vortices. The temperature location of the vortex solidification transition line is not altered by decreasing the sample size although there is a depletion of the entropy jump at the transition with respect to macroscopic vortex matter. The solid order-disorder phase transition field moves upward on decreasing the system size due to the increase of the surface-to-volume ratio of vortices entailing a decrease on the average vortex binding energy.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ Serial 719  
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Author (up) Dolz, M.I.; Bolecek, N.R.C.; Puig, J.; Pastoriza, H.; Nieva, G.; Guimpel, J.; van der Beek, C.J.; Konczykowski, M.; Fasano, Y. url  doi
openurl 
  Title Enhancement of penetration field in vortex matter in mesoscopic superconductors due to Andreev bound states Type Journal Article
  Year 2019 Publication Physical Review B Abbreviated Journal PRB  
  Volume 100 Issue 6 Pages 064508  
  Keywords  
  Abstract We study the field for the penetration of a first vortex, HP, for vortex matter nucleated in micron-sized samples with edges aligned along the nodal and antinodal directions of the d-wave superconducting order parameter of Bi2Sr2CaCu2O8−δ. Here we present evidence that the HP for vortex matter nucleated in mesoscopic samples with edges parallel to the nodal direction is larger than for the antinodal case, ∼72% at low temperatures. This finding supports the theoretical proposal that surface Andreev bound states appearing in a sample with edges parallel to the nodal direction would produce an anomalous Meissner current that increases the Bean-Livingston barrier for vortex penetration.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ 10.1103/PhysRevB.100.064508 Serial 822  
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