Anomalous temperature dependence of the upper critical magnetic field in Bi-Sr-Cu-O

Osofsky, M. S.; Soulen, R. J.; Wolf, Stuart A.; Broto, J.M.; Rakoto, H.; Ousset, J.C.; Coffe, G.; Askénazy, S.; Pari, P.; Božović, I.; Eckstein, J.; Virshup, G. F.

doi:10.1103/physrevlett.71.2315

Cited by 234 publications

(103 citation statements)

References 41 publications

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“…[47]). Such an H c2 agrees reasonably well with the criterion of zero resistance, achieved at about 6 T, and also agrees with the H c2 values reported previously in thin films of PCCO [25,48] and NCCO [48,49] at x = 0.15. A roughly linear growth of κ with field is also seen, for example, in the borocarbide superconductor LuNi 2 B 2 C [34], however with a major difference: in LuNi 2 B 2 C, the field induces a linear term at T → 0.…”

Section: Normal Statesupporting

confidence: 79%

Breakdown of Fermi-liquid theory in a copper-oxide superconductor

Hill

Proust

Taillefer

et al. 2001

Nature

180

189

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The behaviour of electrons in solids is remarkably well described by Landau's Fermi-liquid theory, which says that even though electrons in a metal interact they can still be treated as well-defined fermions, called "quasiparticles". At low temperature, the ability of quasiparticles to transport heat is strictly given by their ability to transport charge, via a universal relation known as the Wiedemann-Franz law, which no material in nature has been known to violate. High-temperature superconductors have long been thought to fall outside the realm of Fermi-liquid theory, as suggested by several anomalous properties, but this has yet to be shown conclusively. Here we report on the first experimental test of the Wiedemann-Franz law in a cuprate superconductor, (Pr,Ce)2CuO4. Our study reveals a clear departure from the universal law and provides compelling evidence for the breakdown of Fermi-liquid theory in high-temperature superconductors.

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Section: Normal Statesupporting

confidence: 79%

Breakdown of Fermi-liquid theory in a copper-oxide superconductor

Hill

Proust

Taillefer

et al. 2001

Nature

180

189

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“…The authors of Ref. 251 has noted that this type of behavior is difficult to explain within any known theory. It is sharply different from the standard behavior of BCS-model.…”

Section: B High-t C Superconductorsmentioning

confidence: 99%

“…In a recent paper 251 Osofsky et al presented the unique data on the temperature dependence of the upper critical field of high-temperature superconductor Bi 2 Sr 2 CuO y in wide temperature interval from T c ≈ 19K to T ≈ 0.005T c , which has shown rather anomalous dependence with positive curvature at any temperature. The authors of Ref.…”

Section: B High-t C Superconductorsmentioning

confidence: 99%

“…Measurements of H c2 in Ref. 251 were performed on epitaxially grown films of Bi 2 Sr 2 CuO y , however it is quite possible that the films were still disordered enough, which can be guessed from rather wide (∼ 7K) superconducting transition. Unfortunately the relevant data, in particular on the value of conductivity of the films studied are absent.…”

Section: B High-t C Superconductorsmentioning

confidence: 99%

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Superconductivity and localization

1997

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We present a review of theoretical and experimental works on the problem of mutual interplay of Anderson localization and superconductivity in strongly disordered systems. Superconductivity exists close to the metalinsulator transition in some disordered systems such as amorphous metals, superconducting compounds disordered by fast neutron irradiation etc. Hightemperature superconductors are especially interesting from this point of view. Only bulk systems are considered in this review. The superconductor-insulator transition in purely two-dimensional disordered systems is not discussed.We start with brief discussion of modern aspects of localization theory including the basic concept of scaling, self-consistent theory and interaction effects. After that we analyze disorder effects on Cooper pairing and superconducting transition temperature as well as Ginzburg-Landau equations for superconductors which are close to the Anderson transition. A necessary generalization of usual theory of "dirty" superconductors is formulated which allows to analyze anomalies of the main superconducting properties close to disorder-induced metal-insulator transition. Under very rigid conditions superconductivity may persist even in the localized phase (Anderson insulator).Strong disordering leads to considerable reduction of superconducting transition temperature T c and to important anomalies in the behavior of the upper critical field H c2 . Fluctuation effects are also discussed. In the vicinity of Anderson transition inhomogeneous superconductivity appears due to statistical fluctuations of the local density of states.We briefly discuss a number of experiments demonstrating superconductivity close to the Anderson transition both in traditional and high-T c superconductors. In traditional systems superconductivity is in most cases destroyed before metal-insulator transition. In case of high-T c superconductors a number of anomalies show that superconductivity is apparently conserved in the localized phase before it is suppressed by strong enough disorder. The concept of electron localization 1 is basic for the understanding of electron properties of disordered systems 2,3 . In recent years a number of review papers had appeared, extensively discussing this problem [4][5][6][7] . According to this concept introduction of sufficiently strong disorder into a metallic system leads to spatial localization of electronic states near the Fermi level and thus to a transition to dielectric state (Anderson transition). After this transition dc conductivity (at zero temperature, T = 0) vanishes, despite the finite value of electronic density of states at the Fermi level (at least in one-electron approximation).At the same time it is well-known that even the smallest attraction of electrons close to the Fermi level leads to formation of Cooper pairs and the system becomes superconducting at sufficiently low temperatures 8,9 . It is known that the introduction of disorder which does not break the time-reversal invariance (normal, nonm...

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“…Above T c , the uniform magnetic susceptibility is paramagnetic and the resistivity is perfectly "normal," showing only a few percent positive or negative magnetoresistance (MR). Both in-plane [11][12][13] and out-of-plane 9 resistive transitions remain sharp in the magnetic field in high-quality samples, providing a reliable determination of a genuine H c2 ͑T͒. As concerns the anomalous thermomagnetic effects, a simple normal-state model with itinerant and localized carriers provides a quantitative single-parameter description of both the temperature and field dependencies of the Nernst signal measured experimentally above the resistive critical temperature T c ͑B͒ (see Ref.…”

mentioning

confidence: 99%