Variation of the Critical Fields of Superconducting Lead with the Residual Resistivity

Druyvesteyn, W.F.; Ooijen, D.J. van; Berben, T.J.

doi:10.1103/revmodphys.36.58

Cited by 27 publications

(6 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was often attributed to defects and insufficient sensitivity of magnetometers (see, e.g. [13]) and therefore ignored in theories (e.g., [14]). Saint-James and de Gennes treated superconductivity above H c2 as an equilibrium property, thus providing an interpretation of the entire phase diagram within one theory.…”

Section: Pacs Numbersmentioning

confidence: 99%

Equilibrium properties of superconducting niobium at high magnetic fields: A possible existence of a filamentary state in type-II superconductors

et al. 2017

View full text Add to dashboard Cite

The standard interpretation of the phase diagram of type-II superconductors was developed in 1960s and has since been considered a well-established part of classical superconductivity. However, upon closer examination a number of fundamental issues arise that leads one to question this standard picture. To address these issues we studied equilibrium properties of niobium samples near and above the upper critical field Hc2 in parallel and perpendicular magnetic fields. The samples investigated were very high quality films and single crystal discs with the Ginzburg-Landau parameters 0.8 and 1.3, respectively. A range of complementary measurements have been performed, which include dc magnetometry, electrical transport, µSR spectroscopy and scanning Hall-probe microscopy. Contrarily to the standard scenario, we observed that a superconducting phase is present in the sample bulk above Hc2 and the field Hc3 is the same in both parallel and perpendicular fields. Our findings suggest that above Hc2 the superconducting phase forms filaments parallel to the field regardless on the field orientation. Near Hc2 the filaments preserve the hexagonal structure of the preceding vortex lattice of the mixed state and the filament density continuously falls to zero at Hc3. Our work has important implications for the correct interpretation of properties of type-II superconductors and can also be essential for practical applications of these materials. PACS numbers:Interpretation of equilibrium properties of superconductors has a pivotal significance for the entire realm of quantum physics, extending from neutron stars to the standard model [1,2]. Therefore it is important to verify any concern related to description of these properties.Type-II superconductors subjected to a magnetic field H above the lower critical field H c1 can be found in three equilibrium states [3,4,6,7]: in the mixed state (MS), where average magnetic inductionB < H and currents form vortices organized in a hexagonal lattice; in a "surface superconductivity" state, where B = H everywhere except a sheath with thickness of the order of the Ginzburg-Landau (GL) coherence length near the surface parallel to H; and in the normal state (NS). The typical phase diagram of type-II superconductors of cylindrical geometry (such as, e.g., infinite circular cylinders and slabs with thickness greatly exceeding the penetration depth) in parallel magnetic field, or of massive samples with demagnetizing factor η = 1 [5] is shown in Fig. 1. Transitions between states, occurring at the critical fields H c2 and H c3 , are second order phase transitions. In ellipsoidal samples with η = 0 the sheath formes an equatorial band whose width decreases with increasing η. In samples with η = 1 (infinite slabs in perpendicular field) the band vanishes and surface superconductivity disappears. Since MS in such samples starts from H = (1−η)H c1 = 0, their phase diagram consists of a single curve H c2 . This interpretation of the properties of type-II superconductors is based on two well kno...

show abstract

Section: Pacs Numbersmentioning

confidence: 99%

Equilibrium properties of superconducting niobium at high magnetic fields: A possible existence of a filamentary state in type-II superconductors

et al. 2017

View full text Add to dashboard Cite

show abstract

“…2A, and SI Appendix, Figs. S3-S5) (5)(6)(7)(8). Single crystals of the same doping from different batches and grown by different groups show similarly high irreversible magnetic fields…”

mentioning

confidence: 98%

Unconventional quantum vortex matter state hosts quantum oscillations in the underdoped high-temperature cuprate superconductors

Hsu

Hartstein

Davies

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

A central question in the underdoped cuprates pertains to the nature of the pseudogap ground state. A conventional metallic ground state of the pseudogap region has been argued to host quantum oscillations upon destruction of the superconducting order parameter by modest magnetic fields. Here, we use low applied measurement currents and millikelvin temperatures on ultrapure single crystals of underdoped YBa2Cu3O6+x to unearth an unconventional quantum vortex matter ground state characterized by vanishing electrical resistivity, magnetic hysteresis, and nonohmic electrical transport characteristics beyond the highest laboratory-accessible static fields. A model of the pseudogap ground state is now required to explain quantum oscillations that are hosted by the bulk quantum vortex matter state without experiencing sizable additional damping in the presence of a large maximum superconducting gap; possibilities include a pair density wave.

show abstract

“…T h e rather involved analysis of their results led these authors to conclude that equation (2.40) and the theoretical expression for K l ( t ) / K were verified to within about 4%. I n fact, the precision of the observations which are now becoming available is approaching the point where it might be worth while using the exact equation ( 2 (Livingston (1963) for various lead I alloys, Druyvesteyn et al (1964) for lead-indium alloys, Joiner and Blaugher (1964) for molybdenum-rhenium alloys, Rosenblum et al (1964) for niobium alloys, Kinsel et al (1962) for indium-bismuth alloys and DeSorbo (1963 a) for niobium alloys) merely indicate that ~~( t ) and K l ( t ) did not differ by more than about 2076 for these specimens. There was therefore a corresponding lack of precision in the verification of the equation K ~( 1) = K ~( 1) which must hold at temperatures where the GL equations are valid.…”

Section: Mixedmentioning

confidence: 99%

Type II superconductors

Goodman¹

1966

Rep. Prog. Phys.

View full text Add to dashboard Cite

Contents 1. Introduction . 2. The Ginzburg-Landau equations . 2.1. Introduction . 2.2. The range of coherence and the penetration depth 2.3. T h e upper critical field Hc2 . . 3. Vortex lines. 4. The reversible magnetic behaviour of type I1 superconductors . 4.1. The vortex line tension and the initial penetration field H,, . 4.2. The magnetic behaviour at low fields and the evidence for the existence of vortex lines . 4.3. The magnetic behaviour near Hc2 and the thermodynamic properties of the mixed state at arbitrary temperatures , 4.4. T h e influence of the paramagnetism of the normal state. 4.5. The superconducting sheath : supercooling . 5.1. The static irreversible magnetic behaviour 5.2. Flux motion . Acknowledgments . References .

show abstract

Variation of the Critical Fields of Superconducting Lead with the Residual Resistivity

Cited by 27 publications

References 10 publications

Equilibrium properties of superconducting niobium at high magnetic fields: A possible existence of a filamentary state in type-II superconductors

Equilibrium properties of superconducting niobium at high magnetic fields: A possible existence of a filamentary state in type-II superconductors

Unconventional quantum vortex matter state hosts quantum oscillations in the underdoped high-temperature cuprate superconductors

Type II superconductors

Contact Info

Product

Resources

About