Topic
High-temperature superconductivity
About: High-temperature superconductivity is a research topic. Over the lifetime, 7263 publications have been published within this topic receiving 175377 citations. The topic is also known as: high-temperature superconductivity.
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TL;DR: The coupling strength inferred from results is sufficient to account for the high transition temperatures of the copper oxides, highlighting a prominent role for spin fluctuations in driving superconductivity in these materials.
Abstract: In conventional superconductors, the most direct evidence of the mechanism responsible for superconductivity comes from tunnelling experiments, which provide a clear picture of the underlying electron–phonon interactions1,2. As the coherence length in conventional superconductors is large, the tunnelling process probes several atomic layers into the bulk of the material; the observed structure in the current–voltage characteristics at the phonon energies gives1, through inversion of the Eliashberg equations, the electron–phonon spectral density α2F(ω). The situation is different for the high-temperature copper oxide superconductors, where the coherence length (particularly for c-axis tunnelling) can be very short. Because of this, methods such as optical spectroscopy and neutron scattering provide a better route for investigating the underlying mechanism, as they probe bulk properties. Accurate reflection measurements at infrared wavelengths and precise polarized neutron-scattering data are now available for a variety of the copper oxides3,4,5, and here we show that the conducting carriers (probed by infrared spectroscopy) are strongly coupled to a resonance structure in the spectrum of spin fluctuations (measured by neutron scattering). The coupling strength inferred from those results is sufficient to account for the high transition temperatures of the copper oxides, highlighting a prominent role for spin fluctuations in driving superconductivity in these materials.
153 citations
TL;DR: In this paper, the influence of lattice strain and Mg vacancies on the superconducting properties of MgB2 samples has been investigated, and it was found that high strain and the presence of mg vacancies resulted in a reduction in the Tc by only 2 K.
Abstract: The influence of lattice strain and Mg vacancies on the superconducting properties of MgB2 samples has been investigated. High quality samples with sharp superconducting transitions were synthesized. The variations in lattice strain and Mg vacancy concentrations were obtained by varying the synthesis conditions. It was found that high strain (∼1%) and the presence of Mg vacancies (∼5%) resulted in lowering the Tc by only 2 K.
153 citations
TL;DR: In this paper, a theoretical analysis in terms of an extended Lindemann criterion provides a quantitative description of the resulting vortex-matter phase boundaries and the behavior of the transition lines with varying anisotropy and disorder.
Abstract: The vortex-matter in superconductors is generally believed to exist in two main phases, vortex-solid and vortex-liquid. Recent investigations of the phase diagram of anisotropic high-temperature superconductors indicate, however, the existence of at least three distinct phases: relatively ordered quasi-lattice, highly-disordered entangled vortex-solid, and a liquid phase. A theoretical analysis in terms of an extended Lindemann criterion provides a quantitative description of the resulting vortex-matter phase boundaries and the behavior of the transition lines with varying anisotropy and disorder.
152 citations
TL;DR: In this paper, the discovery of high-temperature superconductors has stimulated dramatic growth in the understanding of the physics of quantized vortex lines, and the behavior of vortices dominates many physical properties of high temperature superconductions up to the upper critical field Hc2∼102 tesla, where superconductivity gives way to normal metallic behavior and magnetic fields penetrate uniformly.
Abstract: The discovery of high‐temperature superconductors has stimulated dramatic growth in our understanding of the physics of quantized vortex lines. These superconductors exclude magnetic fields weaker than a lower critical field Hc1≤10−2 tesla. Stronger fields penetrate as an array of vortices, each consisting of exactly one quantum of flux (φ0 = hc/2e) surrounded in the plane perpendicular to the field by circulating supercurrents that extend radially a few hundred nanometers. The behavior of vortices dominates many physical properties of high‐temperature superconductors up to the upper critical field Hc2∼102 tesla, where superconductivity gives way to normal metallic behavior and magnetic fields penetrate uniformly.
152 citations
TL;DR: A model combining thermally activated motion of flux lines, viscous flux flow at high current density, and distribution of activation energies is shown to reproduce the characteristic features of current-voltage curves of high-{ital T}{sub {ital c}} superconductors.
Abstract: A model combining thermally activated motion of flux lines, viscous flux flow at high current density, and distribution of activation energies is shown to reproduce the characteristic features of current-voltage curves of high-${\mathit{T}}_{\mathit{c}}$ superconductors. In particular the recent data of Koch et al. and Zeldov et al. can be explained without invoking a continuous phase transition (freezing into a superconducting vortex-glass phase) or a logarithmic current dependence of the activation energy.
151 citations