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Your search keyword '"Cadorim, Leonardo Rodrigues"' showing total 12 results
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12 results on '"Cadorim, Leonardo Rodrigues"'

1. Describing heat dissipation in the resistive state of three-dimensional superconductors

Author

Cadorim, Leonardo Rodrigues, de Toledo, Lucas Veneziani, and Sardella, Edson

Subjects
Condensed Matter - Superconductivity
Abstract

In this work we study the role of the heat diffusion equation in simulating the resistive state of superconducting films. By analyzing the current-voltage and current-resistance characteristic curves for temperatures close to $T_c$ and various heat removal scenarios, we demonstrate that heat diffusion notably influences the behavior of the resistive state, specially near the transition to the normal state, where heat significantly changes the critical current and the calculated resistance. Furthermore, we show how the efficiency of the substrate has important effects in the dynamics of the system, particularly for lower temperatures. Finally, we investigate the hysteresis loops, the role of the film thickness and of the Ginzburg-Landau parameter, the findings accounting for heat diffusion in accurately modeling the resistive state of superconducting films and provide valuable insights into its complex dynamics. To accomplish these findings, we have used the $3D$ generalized Ginzburg-Landau equation coupled with the heat diffusion equation., Comment: Published in Physica C: Superconductivity and its applications

Published
2024
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2. Harnessing the superconducting diode effect through inhomogeneous magnetic fields

Author

Cadorim, Leonardo Rodrigues, Sardella, Edson, and Silva, Clécio Clemente de Souza

Subjects
Condensed Matter - Superconductivity
Abstract

We propose a superconducting diode device comprising a central superconducting film flanked by two wires carrying an applied DC bias, suitably chosen so as to generate different asymmetric field profiles. Through numerical simulations of the coupled Ginzburg-Landau and heat-diffusion equations, we show that this design is capable of efficiently breaking the reciprocity of the critical current in the central superconductor, thus promoting the diode effect in response to an applied AC current. By adjusting the DC bias in the wires, we find the optimum inhomogeneous field profile that facilitates the entrance of vortices and antivortices in a given polarity of the applied AC current and impede their entrance in the other polarity. This way, the system behaves as an ideal superconducting half-wave rectifier, with diode efficiencies surpassing 70%. Furthermore, we detail the behavior and diode efficiency of the system under different experimental conditions, such as the substrate heat transfer coefficient and the sweep rate of the external current., Comment: 13 pages, 14 figures

Published
2024
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3. Closed vortex state in 3D mesoscopic superconducting films under an applied transport current

Author

Cadorim, Leonardo Rodrigues, de Toledo, Lucas Veneziani, Ortiz, Wilson Aires, Berger, Jorge, and Sardella, Edson

Subjects
Condensed Matter - Superconductivity
Abstract

By using the full 3D generalized time dependent Ginzbug-Landau equation we study a long superconducting film of finite width and thickness under an applied transport current. We show that, for sufficiently large thickness, the vortices and the antivortices become curved before they annihilate each other. As they approach the center of the sample, their ends combine, producing a single closed vortex. We also determine the critical values of the thickness for which the closed vortex sets in for different values of the Ginzburg-Ladau parameter. Finally, we propose a model of how to detect a closed vortex experimentally., Comment: 9 pages, 10 figures, accepted for publication in Phys. Rev. B

Published
2023

4. Ultra-fast Kinematic Vortices in Mesoscopic Superconductors: The Effect of the Self-Field

Author

Cadorim, Leonardo Rodrigues, Junior, Alexssandre de Oliveira, and Sardella, Edson

Subjects
Condensed Matter - Superconductivity
Abstract

Within the framework of the generalized time-dependent Ginzburg-Landau equations, we studied the influence of the magnetic self-field induced by the currents inside a superconducting sample driven by an applied transport current. The numerical simulations of the resistive state of the system show that neither material inhomogeneity nor a normal contact smaller than the sample width are required to produce an inhomogeneous current distribution inside the sample, which leads to the emergence of a kinematic vortex-antivortex pair (vortex street) solution. Further, we discuss the behaviors of the kinematic vortex velocity, the annihilation rates of the supercurrent, and the superconducting order parameters alongside the vortex street solution. We prove that these two latter points explain the characteristics of the resistive state of the system. They are the fundamental basis to describe the peak of the current-resistance characteristic curve and the location where the vortex-antivortex pair is formed., Comment: 9 pages, 6 figures. Accepted for publication in Scientific Reports

Published
2020

7. The spike state in type-I mesoscopic superconductor

Author

Oliveira, Isaias Gonzaga de, Cadorim, Leonardo Rodrigues [UNESP], Romaguera, Antonio Rodrigues de Castro, Sardella, Edson [UNESP], Gomes, Rodolfo Ribeiro, Doria, Mauro Melchiades, and Universidade Estadual Paulista (Unesp)

Subjects
Superconductivity, Type-I superconductivity, Time-dependent Ginzburg-Landau equation, Spike state
Abstract

Submitted by Leonardo Rodrigues Cadorim (leonardo.cadorim@unesp.br) on 2021-06-28T22:48:22Z No. of bitstreams: 1 The_spike_state_in_type-I_mesoscopic_superconductor.pdf: 1334460 bytes, checksum: 2efc27cf159e8595ad085dcba85d2eb0 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2021-07-13T14:15:36Z (GMT) No. of bitstreams: 1 cadorim_lr_versaofinaldoeditor_bauru_spike.pdf: 1334460 bytes, checksum: 2efc27cf159e8595ad085dcba85d2eb0 (MD5) Made available in DSpace on 2021-07-13T14:15:36Z (GMT). No. of bitstreams: 1 cadorim_lr_versaofinaldoeditor_bauru_spike.pdf: 1334460 bytes, checksum: 2efc27cf159e8595ad085dcba85d2eb0 (MD5) Previous issue date: 2021-05-28 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) We study here the spike state found in mesoscopic type I superconductors whose existence is confined to the single field where the superconducting state arises from the normal state in descending field in the so-called genuine type I regime. The mesoscopic type I superconductor possesses distinct κregimes due to its richer critical field structure Cadorim et al. (2021) [11]. The lifetime of the spike state is shown to be in the nanosecond scale through the time dependent Ginzburg-Landau (TDGL) equations. The spike state is a giant vortex state that undergoes a process of deformation after its creation when several bubbles of vortices are expelled forming new but deformed giant vortices until no one is left inside the superconductor. Like phase slips and kinematic vortices, the spike state is also a non-equilibrium vortex state Departamento de Física, Universidade Federal Rural do Rio de Janeiro, CEP 23890-000 Seropdica, RJ, Brazil Departamento de Física, Faculdade de Ciências, Universidade Estadual Paulista (UNESP), Caixa Postal 473, 17033-360, Bauru-SP, Brazil Departamento de Física, Universidade Federal Rural de Pernambuco, 52171-900 Recife, Pernambuco, Brazil Instituto de Física, Universidade Federal do Rio de Janeiro, 21941-972 Rio de Janeiro, Brazil and Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-970 Campinas, São Paulo, Brazil FAPESP: 20/03947-2

Published
2021

9. Ultra‑fast kinematic vortices in mesoscopic superconductors: the effect of the self‑field

Author

Cadorim, Leonardo Rodrigues [UNESP], Oliveira Junior, Alexandre de, Sardella, Edson [UNESP], and Universidade Estadual Paulista (Unesp)

Subjects
Vortex matter, Time-dependent Ginzburg-Landau equations, Superconductivity, Type-I superconductivity
Abstract

Submitted by Leonardo Rodrigues Cadorim (leonardo.cadorim@unesp.br) on 2021-06-28T22:03:56Z No. of bitstreams: 1 Ultra-fast_vortices_in_mesoscopic_superconductors_the_effect_of_the_self_field.pdf: 1307095 bytes, checksum: 715b8712940f3aae64867bab51152200 (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2021-07-12T23:29:25Z (GMT) No. of bitstreams: 1 cadorim_lr_versaofinaldoeditor_bauru_ultra-fast.pdf: 1307095 bytes, checksum: 715b8712940f3aae64867bab51152200 (MD5) Made available in DSpace on 2021-07-12T23:29:26Z (GMT). No. of bitstreams: 1 cadorim_lr_versaofinaldoeditor_bauru_ultra-fast.pdf: 1307095 bytes, checksum: 715b8712940f3aae64867bab51152200 (MD5) Previous issue date: 2020-10-29 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) In the present work, we have studied the crossover between type I and type II superconductivity on mesoscopic superconducting thin films by numerically solving the 3D Ginzburg-Landau equations. We determined the dependence on temperature of the critical Ginzburg-Landau parameter kc(d), below which the superconductor behaves as type I for a given thickness d of the film. The effect of the sample dimensions on this crossover was also investigated. Additionally, we report a novel giant vortex configuration with a local minimum of the magnetic field at the centre of the core. Finally, we present certain results suggesting that the vortex-vortex interaction is not monotonic, varying instead from long-range attraction to short-range repulsion. Departamento de Física, Faculdade de Ciências, Universidade Estadual Paulista (UNESP), Caixa Postal 473, 17033-360, Bauru-SP, Brazil Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, P.O. Box 6165, Campinas, Sao Paulo CEP 13083‑970, Brazil FAPESP: 20/03947-2

Published
2020

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