BT Home

BT Literature Database

Home |  Show All |  Simple Search |  Advanced Search
Quick Search:
1-10 of 15 records found matching your query:
toggle visibility Search & Display Options
Select All    Deselect All << 1 2 >>
List View
 | 
Citations
 | 
Details
   print
  Records Links
Author (up) Antonio, D.; Dolz, M.I.; Pastoriza, H. url  doi
openurl 
  Title Magnetization measurement of single La0.67Ca0.33MnO3 nanotubes in perpendicular magnetic fields using a micromechanical torsional oscillator Type Journal Article
  Year 2010 Publication Journal of Magnetism and Magnetic Materials Abbreviated Journal  
  Volume 322 Issue 5 Pages 488-493  
  Keywords Manganite nanotubes; Micromachined magnetometers; Shape anisotropy  
  Abstract Using a silicon micromechanical resonator as a sensitive magnetometer, the authors have studied both experimentally and theoretically the magnetic behavior of two isolated ferromagnetic nanotubes of perovskite La0.67Ca0.33MnO3. The article investigates the specific configuration where a magnetic field H is applied perpendicular to the magnetic easy axis of an isolated nanotube characterized by an uniaxial anisotropy constant K. In this situation, the magnetization M reduces the effective elastic constant kM of the resonator. This softening of the mechanical system is opposed to the hardening effect of M observed in a previous work, where H was applied parallel to the easy axis. Moreover, in this magnetic field configuration two distinct magnetization regimes are manifested, depending on the magnitude of H. For H[not double greater-than sign]2K/M the magnetization is almost parallel to the applied magnetic field and for H[double less-than sign]2K/M it is almost parallel to the easy axis of the nanotube. At a certain value of H there is a sharp transition  
  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 0304-8853 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ 13272 Serial 585  
Permanent link to this record
 
 
Author (up) Antonio, D.; Dolz, M.I.; Pastoriza, H. url  openurl
  Title Micromechanical magnetometer using an all-silicon nonlinear torsional resonator Type Journal Article
  Year 2009 Publication Applied Physics Letters Abbreviated Journal Appl. Phys. Lett.  
  Volume 95 Issue 13 Pages 133505-3  
  Keywords damping; eddy currents; elemental semiconductors; magnetometers; micromechanical devices; nonlinear dynamical systems; oscillations; Q-factor; resonators; silicon  
  Abstract In this work, a micromagnetometer employing a nonlinear torsional resonator with a high quality factor Q is presented experimentally. Oscillatory rotation of a conducting plate in the sensed magnetic field H induces eddy currents that dissipate energy. Due to the nonlinear response of the oscillator, the resulting mechanical damping originates frequency shifts in the resonance curve that depend on H. Nonlinearity results from the electrostatic detection, which introduces high order electrical spring constants. The device is fabricated with a standard silicon process and does not incorporate ferromagnetic materials. An analytical nonlinear model that correctly describes the device is also introduced.  
  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 @ hernan @ Serial 564  
Permanent link to this record
 
 
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  
Permanent link to this record
 
 
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.  
  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 2214-7853 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 852  
Permanent link to this record
 
 
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  
Permanent link to this record
 
 
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  
Permanent link to this record
 
 
Author (up) Dolz, M.I.; Bast, W.; Antonio, D.; Pastoriza, H.; Curiale, J. Sánchez, R. D.; Leyva, A. G. doi  openurl
  Title Magnetic Behavior of Single La0.67Ca0.33MnO$_3$ Nanotubes: Surface and Shape Effects Type Journal Article
  Year 2008 Publication J. Appl. Phys. Abbreviated Journal  
  Volume 103 Issue Pages 083909  
  Keywords  
  Abstract We report magnetization experiments in two magnetically isolated ferromagnetic nanotubes of perovskite Lai0.67Ca0.33MnO$_3$. The results show that the magnetic anisotropy is determined by the sample shape, although the coercive field is reduced by incoherent magnetization reversal modes. The temperature dependence of the magnetization reveals that the magnetic behavior is dominated by grain surface properties. These measurements were acquired using a silicon micromechanical oscillator working in its resonant mode. The sensitivity was enough to measure the magnetic properties of these two samples with a mass lower than 14 pg and to obtain for the first time the magnetization loop for one isolated nanotube.  
  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 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ dolz08 Serial 17  
Permanent link to this record
 
 
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  
Permanent link to this record
 
 
Author (up) Dolz, M.I.; Kolton, A.B.; Pastoriza, H. url  doi
openurl 
  Title Direct determination of the collective pinning radius in the cuprate superconductor Bi2 Sr2 CaCu2 O8+ delta Type Journal Article
  Year 2010 Publication Physical Review B Abbreviated Journal PRB  
  Volume 81 Issue 9 Pages 092502  
  Keywords  
  Abstract We study the onset of the irreversible magnetic behavior of vortex matter in micron-sized Bi2Sr2CaCu2O8+δ single crystals by using silicon micro-oscillators. We find an irreversibility line appearing well below the thermodynamic Bragg-glass melting line at a magnetic field which increases both with increasing the sample radius and with decreasing the temperature, paradoxically implying the existence of a reversible vortex solid. We show that at this irreversibility line, the sample radius can be identified with the crossover length between the Larkin and the random-manifold regimes of the vortex-lattice transverse roughness. Our method thus allows to determine, as a function of temperature and applied magnetic field, the minimum size of a vortex system that can be collectively pinned, or the so-called three-dimensional weak collective pinning Larkin radius, in a direct way.  
  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 587  
Permanent link to this record
 
 
Author (up) Dolz, M.I.; Pastoriza, H. url  openurl
  Title Dependence of vortex phase transitions in mesoscopic Bi2Sr2CaCuO8 superconductor at tilted magnetic fields Type Journal Article
  Year 2009 Publication Journal of Physics: Conference Series Abbreviated Journal  
  Volume 150 Issue 5 Pages 052044-4  
  Keywords  
  Abstract A micron sized single crystal of the superconductor Bi2Sr2CaCuO8 was studied using silicon mechanical micro-oscillators at various tilt angles of the dc magnetic field with respect to the c axis of the sample. Different phases of the vortex matter were detected by measuring changes in the value and sign of the oscillator resonant frequency variation with temperature. We could explain the change in the sign of this variation at high temperatures as the transition from the 2D liquid of decoupled pancakes to a reversible 3D vortex lattice. The data indicates that this transition only depends on the magnetic field perpendicular to the superconducting layers while the dissipation involved in this process depends on the component parallel to them.  
  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 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ hernan @ dolz09 Serial 311  
Permanent link to this record
Select All    Deselect All << 1 2 >>
List View
 | 
Citations
 | 
Details
   print
toggle visibility
Save Citations:
Export Records:
Home CQL Search  |  Library Search  |  Show Record  |  Extract Citations Help