Magnetic levitation of YBa2Cu3Oy single crystals

Chan, W. C.; Jwo, D. S.; Lin, Yu; Huang, Yen-Chieh

doi:10.1016/0921-4534(94)90850-8

Cited by 13 publications

(4 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although plate like crystallites did align their (a, b) plane parallel H 0 , levitation was nevertheless observed. These observations seem to be in contrast to measurements of the levitation force which reported that the force parallel (a, b) plane was too small to be measured [44].…”

Section: The Effect Of Torquecontrasting

confidence: 88%

Theory of high gradient attractive magnetic separation of superconducting materials and its experimental verification by YBa₂Cu₃O_xparticles

Dessauges

Willems

Favre

et al. 2006

Supercond. Sci. Technol.

View full text Add to dashboard Cite

The calculation of trajectories for sedimenting diamagnetic particles shows that superconducting matter in the Meissner or vortex state can be captured sidewise to a ferromagnetic wire magnetized perpendicular to its length. Capture is possible for externally applied fields lower than typical critical fields H c1 (c), H c1 (a, b) of cuprates. For single crystalline particles in the vortex state, the magnetic anisotropy may reduce the capture force because of alignment. Theoretical predictions were confirmed experimentally for suspensions of polycrystalline and single crystalline particles of YBa 2 Cu 3 O x (size range: 2-125 µm) in liquid nitrogen. As a general conclusion we find that for the extraction of superconducting particles out of combinatorial ceramic reaction mixtures, separation in the Meissner state might be most effective because of the presence of an excess of normal state matter featuring a much lower diamagnetic susceptibility.

show abstract

Section: The Effect Of Torquecontrasting

confidence: 88%

Theory of high gradient attractive magnetic separation of superconducting materials and its experimental verification by YBa₂Cu₃O_xparticles

Dessauges

Willems

Favre

et al. 2006

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Another mechanical effect of pinning is a strong "internal friction" which enables superconductors to levitate above (or below) an asymmetric permanent magnet motionless, without oscillation or rotation, figure 12, since part of the magnetic field lines is pinned inside the specimen in form of flux lines (Moon et al 1988, Brandt 1988c, 1989c, Kitaguchi et al 1989). Levitation forces were calculated by various authors (Nemoshkalenko et al 1990, Yang et al 1992, Huang et al 1993, Barowski et al 1993, Chan et al 1994, Haley 1995, Coffey 1995.…”

Section: Pinning Of Flux Lines By Materials Inhomogeneitiesmentioning

confidence: 99%

The flux-line lattice in superconductors

1995

View full text Add to dashboard Cite

Magnetic flux can penetrate a type-II superconductor in form of Abrikosov vortices (also called flux lines, flux tubes, or fluxons) each carrying a quantum of magnetic flux φ 0 = h/2e. These tiny vortices of supercurrent tend to arrange in a triangular flux-line lattice (FLL) which is more or less perturbed by material inhomogeneities that pin the flux lines, and in high-T c superconductors (HTSC's) also by thermal fluctuations. Many properties of the FLL are well described by the phenomenological Ginzburg-Landau theory or by the electromagnetic London theory, which treats the vortex core as a singularity. In Nb alloys and HTSC's the FLL is very soft mainly because of the large magnetic penetration depth λ: The shear modulus of the FLL is c 66 ∼ 1/λ 2 , and the tilt modulus c 44 (k) ∼ (1 + k 2 λ 2 ) −1 is dispersive and becomes very small for short distortion wavelength 2π/k ≪ λ. This softness is enhanced further by the pronounced anisotropy and layered structure of HTSC's, which strongly increases the penetration depth for currents along the c-axis of these (nearly uniaxial) crystals and may even cause a decoupling of two-dimensional vortex lattices in the Cu-O layers. Thermal fluctuations and softening may "melt" the FLL and cause thermally activated depinning of the flux lines or of the two-dimensional "pancake vortices" in the layers. Various phase transitions are predicted for the FLL in layered HTSC's. Although large pinning forces and high critical currents have been achieved, the small depinning energy so far prevents the application of HTSC's as conductors at high temperatures except in cases when the applied current and the surrounding magnetic field are small.

show abstract

“…Hellman et al 14 and Yang 15 presented models based on total flux exclusion of the sample that thus describe the behavior of type-I superconductors or type-II samples with very high critical current. Schönhuber and Moon, 16 Chan et al, 17 and Torng and Chen 18 have taken into account the penetration of supercurrents, the latter with an applied field provided by a pair of oppositely wound coils. In Ref.…”

Section: Introductionmentioning

confidence: 99%

Magnetic levitation of superconductors in the critical state

Navau

Sanchez

1998

Phys. Rev. B

View full text Add to dashboard Cite

The vertical levitation force in a cylindrically symmetric system composed of a permanent magnet and a type-II superconductor is studied assuming the latter to be in a critical state. In a first step, a constant-fieldgradient approximation along the length of the superconductor is used to see the effects of the dependence of the critical current density on the internal magnetic field. In a second step, the theory is generalized in order to study the case when the field gradient is not constant, as is usually found in levitation experiments with bulk superconducting samples. The model results are discussed in relation to recent experimental data on magnetic levitation of high-T c superconductors, explaining the observed behavior and making some predictions for future experiments. ͓S0163-1829͑98͒00426-3͔

show abstract

Magnetic levitation of YBa2Cu3Oy single crystals

Cited by 13 publications

References 12 publications

Theory of high gradient attractive magnetic separation of superconducting materials and its experimental verification by YBa₂Cu₃O_xparticles

Theory of high gradient attractive magnetic separation of superconducting materials and its experimental verification by YBa₂Cu₃O_xparticles

The flux-line lattice in superconductors

Magnetic levitation of superconductors in the critical state

Contact Info

Product

Resources

About

Magnetic levitation of YBa2Cu3Oy single crystals

Cited by 13 publications

References 12 publications

Theory of high gradient attractive magnetic separation of superconducting materials and its experimental verification by YBa2Cu3Oxparticles

Theory of high gradient attractive magnetic separation of superconducting materials and its experimental verification by YBa2Cu3Oxparticles

The flux-line lattice in superconductors

Magnetic levitation of superconductors in the critical state

Contact Info

Product

Resources

About

Theory of high gradient attractive magnetic separation of superconducting materials and its experimental verification by YBa₂Cu₃O_xparticles

Theory of high gradient attractive magnetic separation of superconducting materials and its experimental verification by YBa₂Cu₃O_xparticles