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Dolan, G. J.; Holtzberg, F.; Feild, C.; Dinger, T. R.

doi:10.1103/physrevlett.62.2184

Cited by 227 publications

(69 citation statements)

References 18 publications

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“…From fits to the ellipse of scattering, a value for γ of 1.18(2) was obtained. This is slightly higher than the 1.13 estimated by Bitter decoration [6], but in the lower range of values found by polarized reflectivity, γ=1.3-1.6 [9], and Josephson tunnel junctions, γ=1.2-1.7 [10]. That the variability is between samples rather than techniques is borne out by µSR measurements on the same sample which give γ=1.16(2) [21].…”

mentioning

confidence: 75%

“…Observations require a probe sensitive to the microscopic arrangement of fluxlines. Direct imaging [5] and decoration techniques [6] all have inherent drawbacks, and muon spin rotation has not yet achieved the sophistication to resolve the most subtle effects [7]. By comparison, small angle neutron scattering (SANS) provides unrivalled insights into the crystallography of the FLL, and is the only technique capable of unequivocably resolving such questions.…”

mentioning

confidence: 99%

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Flux-Line Lattice Structures in UntwinnedYBa2Cu3O7−δ
Johnson
¹
,
Forgan
²
,
Lloyd
³

et al. 1999
Phys. Rev. Lett.
50
12
46
0
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A small angle neutron scattering study of the flux-line lattice in a large single crystal of untwinned YBa2Cu3O 7−δ is presented. In fields parallel to the c-axis, diffraction spots are observed corresponding to four orientations of a hexagonal lattice, distorted by the a-b anisotropy. A value for the anisotropy, the penetration depth ratio, of λa/λ b =1.18(2) was obtained. The high quality of the data is such that second order diffraction is observed, indicating a well ordered FLL. With the field at 33 • to c a field dependent re-orientation of the lattice is observed around 3T.PACS numbers: 74.60. Ge, 74.72.Bk, 61.12.Ex The remarkable properties of the mixed state in the cuprate high-T c superconductors are of great current interest. In particular, the expectation that high-T c superconductors have an unconventional pairing symmetry has led inevitably to the question: how does the structure of the flux-line lattice (FLL) differ between conventional and unconventional superconductors? The question has been taken up by several recent theoretical contributions [1][2][3][4] which predict a variety of interesting FLL effects all deviating from the benchmark triangular Abrikosov lattice. However, such discussions may presuppose that the crystallographic properties of the FLL are already well understood in the simplest low-field regime where unconventional effects are least prevalent. This has been far from the experimental truth. Observations require a probe sensitive to the microscopic arrangement of fluxlines. Direct imaging [5] and decoration techniques [6] all have inherent drawbacks, and muon spin rotation has not yet achieved the sophistication to resolve the most subtle effects [7]. By comparison, small angle neutron scattering (SANS) provides unrivalled insights into the crystallography of the FLL, and is the only technique capable of unequivocably resolving such questions.The demanding nature of neutron experiments requires large single crystals (masses > ∼ 200mg), and because of this YBa 2 Cu 3 O 7−δ (YBCO) has been the cuprate of choice for SANS experiments [8]. However, the materials properties of YBCO are complicated. The presence of Cu-O chains which are aligned with the crystallographic b direction render the otherwise tetragonal structure orthorhombic. Upon cooling from the growth, twin boundaries form along {110} directions separating domains of interchanged a and b axes. A strong interaction between flux-lines and these twin planes significantly influences FLL properties. There is a further effect of the chains. Although the orthorhombic distortion is only slight (≈ 1%), the electronic structure is markedly affected, and the consequence is anisotropy within the abplane of both superconducting [9,10] and normal state [11] properties. All previous SANS studies have been on heavily twinned crystals [12,13], and although observations of a pattern with four-fold symmetry were claimed to be due to unconventional d x 2 −y 2 pairing [12], it could not be discounted that alignment by twin planes, in comb...

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mentioning

confidence: 75%

mentioning

confidence: 99%

Flux-Line Lattice Structures in UntwinnedYBa2Cu3O7−δ
Johnson
¹
,
Forgan
²
,
Lloyd
³

et al. 1999
Phys. Rev. Lett.
50
12
46
0
View full text Add to dashboard Cite

show abstract

“…A digital Fourier transform of the pattern is inset in the top corner of the figure, which clearly reveals a strong distortion to the quasi-triangular lattice and an anisotropy of about 1.4±0.05 in the a-b plane. Dolan et al [15] were even able to successfully generate Bitter decoration images in the highly anisotropic a-c plane in YBCO. Fig. 3.2.2 shows such an image of an YBCO single crystal after field cooling to low temperatures in H || =4Oe.…”

Section: Experimental Observations Of Vortex Chains In Moderately Animentioning

confidence: 99%

“…We would also like to express our thanks to the following people who have R is fixed at the optimal value for an isolated chain. [Reproduced with permission from reference [15]. Copyright 1989 American Physical Society] for an extremely dilute density.…”

Section: Acknowledgementsmentioning

confidence: 99%

Vortex chains in anisotropic superconductors

Bending¹,

Dodgson²

2005

J. Phys.: Condens. Matter

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High-cT superconductors in small magnetic fields directed away from the crystal symmetry axes have been found to exhibit inhomogeneous chains of flux lines (vortices), in contrast to the usual regular triangular flux-line lattice. We review the experimental observations of these chains, and summarize the theoretical background that explains their appearance. We treat separately two classes of chains: those that appear in superconductors with moderate anisotropy due to an attractive part of the interaction between tilted flux lines, and those with high anisotropy where the tilted magnetic flux is created by two independent and perpendicular crossing lattices. In the second case it is the indirect attraction between a flux line along the layers (Josephson vortex) and a flux line perpendicular to the layers (pancake vortex stack) that leads to the formation of chains of the pancake vortex stacks. This complex system contains a rich variety of phenomena, with several different equilibrium phases, and an extraordinary dynamic interplay between the two sets of crossing vortices. We compare the theoretical predictions of these phenomena with the experimental observations made to date. We also contrast the different techniques used to make these observations. While it is clear that this system forms a wonderful playground for probing the formation of structures with competing interactions, we conclude that there are important practical implications of the vortex chains that appear in highly anisotropic superconductors.

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“…In the vicinity of H c1 for the tilted magnetic fields the vortex configuration consisting of flux-line chains is predicted [17]. Such vortex chains in the weak field range have been observed in decoration experiments on high-T c superconductors [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Commensurate vortex lattices and oscillation effects in superconducting Mo/Si and W/Si multilayers

Mikhaı̆lov

Yuzephovich

Bomze

et al. 2005

Low Temperature Physics

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We report experimental results of the vortex lattice structure investigation in the artificial superconducting Mo/Si and W/Si superlattices. The resistance R and critical current I c measurements in parallel magnetic fields have been performed as well as measurements in tilted magnetic fields. At temperatures where condition of strong layering is satisfied the dependences I H c ( ) || and R H ( ) || reveal oscillation behavior. It is shown that the appearance of oscillations and of reentrant behavior (vanishing of resistivity in definite ranges of H || ) are due to the strong intrinsic pinning and to the effect of commensurability between the vortex lattice period and multilayer wavelength. The locations of I H c ( ) || and R H ( ) || extrema correspond to the stable states of a commensurate vortex lattice. Our experimental data are in good quantitative agreement with Ivlev, Kopnin, and Pokrovsky (IKP) theory. It is shown that the values of the commensurability fields depend exclusively on the superlattice period s and anisotropy coefficient g and do not depend on the type of materials used for multilayer preparation. The memory effect, i.e., dependence of the oscillation pattern on the magnetic history of the sample, is observed. It is shown experimentally that the state of the vortex matter in the layered superconductors is essentially different from that of type-II superconductors with a random distribution of the pinning centers. Investigation of oscillation and reentrance behavior may be used as a new tool for vortex lattice arrangement study in layered superconductors. The essential advantage of this method is connected with its simplicity and with the possibility of using it in arbitrary large fields. Investigations of the commensurate states may be used for rather precise determination of the anisotropy coefficient g.

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Anisotropic vortex structure inY1Ba2
G. J. Dolan
¹
,
F. Holtzberg
²
,
C. Feild
³

et al.

Cited by 227 publications

References 18 publications

Flux-Line Lattice Structures in UntwinnedYBa2Cu3O7−δ
Johnson
¹
,
Forgan
²
,
Lloyd
³

et al. 1999
Phys. Rev. Lett.
50
12
46
0
View full text Add to dashboard Cite

Flux-Line Lattice Structures in UntwinnedYBa2Cu3O7−δ
Johnson
¹
,
Forgan
²
,
Lloyd
³

et al. 1999
Phys. Rev. Lett.
50
12
46
0
View full text Add to dashboard Cite

Vortex chains in anisotropic superconductors

Commensurate vortex lattices and oscillation effects in superconducting Mo/Si and W/Si multilayers

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Anisotropic vortex structure inY1Ba2G. J. Dolan1, F. Holtzberg2, C. Feild3 et al.

Cited by 227 publications

References 18 publications

Flux-Line Lattice Structures in UntwinnedYBa2Cu3O7−δJohnson1, Forgan2, Lloyd3 et al. 1999Phys. Rev. Lett.5012460View full textAdd to dashboardCite

Flux-Line Lattice Structures in UntwinnedYBa2Cu3O7−δJohnson1, Forgan2, Lloyd3 et al. 1999Phys. Rev. Lett.5012460View full textAdd to dashboardCite

Vortex chains in anisotropic superconductors

Commensurate vortex lattices and oscillation effects in superconducting Mo/Si and W/Si multilayers

Contact Info

Product

Resources

About

Anisotropic vortex structure inY1Ba2
G. J. Dolan
¹
,
F. Holtzberg
²
,
C. Feild
³

et al.

Flux-Line Lattice Structures in UntwinnedYBa2Cu3O7−δ
Johnson
¹
,
Forgan
²
,
Lloyd
³

et al. 1999
Phys. Rev. Lett.
50
12
46
0
View full text Add to dashboard Cite

Flux-Line Lattice Structures in UntwinnedYBa2Cu3O7−δ
Johnson
¹
,
Forgan
²
,
Lloyd
³

et al. 1999
Phys. Rev. Lett.
50
12
46
0
View full text Add to dashboard Cite