Distribution of a local magnetic field in superconductors with an uncorrelated random lattice of abrikosov vortices

Minkin, A. V.; Tsarevskii, S. L.

doi:10.1134/1.1687853

“…18 Such disorder in the VL can produce a symmetric lineshape, 38,50 and can broaden the field distribution significantly compared to that of the corresponding ordered state. 51 Weak random pinning or point-like disorder due to oxygen deficiency may slightly distort the VL, and may also broaden the lineshape.…”

mentioning

confidence: 99%

Vortex lattice disorder inYBa2Cu3O7−δprobed using
Saadaoui
¹
,
MacFarlane
²
,
Salman
³

et al. 2009
Phys. Rev. B
11
1
3
0
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β-detected NMR (β-NMR) has been used to study vortex lattice disorder near the surface of the high-TC superconductor YBa2Cu3O 7−δ (YBCO). The magnetic field distribution from the vortex lattice was detected by implanting a low energy beam of highly polarized 8 Li + into a thin overlayer of silver on optimally doped, twinned and detwinned YBCO samples. The resonance in Ag broadens significantly below the transition temperature TC as expected from the emerging field lines of the vortex lattice in YBCO. However, the lineshape is more symmetric and the dependence on the applied magnetic field is much weaker than expected from an ideal vortex lattice, indicating that the vortex density varies across the face of the sample, likely due to pinning at twin boundaries. At low temperatures the broadening from such disorder does not scale with the superfluid density.

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“…18 Such disorder in the VL can produce a symmetric lineshape, 38,50 and can broaden the field distribution significantly compared to that of the corresponding ordered state. 51 Weak random pinning or point-like disorder due to oxygen deficiency may slightly distort the VL, and may also broaden the lineshape. 39 However, the correlated disorder due to the twin and grain boundaries is dominant at long wavelengths, 40,52 and therefore we are mostly sensitive to the twin/grain boundaries.…”

Section: Discussionmentioning

confidence: 99%

Vortex lattice disorder in YBCO probed using Beta-NMR

Saadaoui,

MacFarlane,

Salman

et al. 2010

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β-detected NMR (β-NMR) has been used to study vortex lattice disorder near the surface of the high-TC superconductor YBa2Cu3O 7−δ (YBCO). The magnetic field distribution from the vortex lattice was detected by implanting a low energy beam of highly polarized 8 Li + into a thin overlayer of silver on optimally doped, twinned and detwinned YBCO samples. The resonance in Ag broadens significantly below the transition temperature TC as expected from the emerging field lines of the vortex lattice in YBCO. However, the lineshape is more symmetric and the dependence on the applied magnetic field is much weaker than expected from an ideal vortex lattice, indicating that the vortex density varies across the face of the sample, likely due to pinning at twin boundaries. At low temperatures the broadening from such disorder does not scale with the superfluid density.

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“…In particular, it is well known that for regular lattices the line shapes are significantly different for lattices of different symmetries [8]. When, however, σ is increasing, these differences tend to average, and the distribution function approximates that of a Gaussian distribution [11]. The calculations demonstrated that a non-uniform field quite rapidly, already at a distance 0.2 (measured in λ units), becomes uniform; hence, the thickness of the films selected should not exceed 0.2.…”

Section: Irregularly Distributed Abrikosov's Vorticesmentioning

confidence: 95%

“…It is well known that an Abrikosov vortex lattice is formed in HTSC in an external magnetic field Н (Н с1 < H < H c2 , H c1 , H c2 are the first and second critical fields). However, the distribution of local magnetic field has so far been calculated for either regular vortex lattices [8 -10] or for the case of complete chaos in the distribution of Abrikosov's vortices -random non-correlated distribution of vortices [11], with no signs of a regular vortex lattice. Nonetheless, the case of a irregular vortex lattice is quite common.…”

mentioning

confidence: 99%

Shape of a magnetic resonance line in a thin film on the surface of anisotropic superconductor with irregularly distributed Abrikosov’s vortices

Minkin

¹

,

Tsarevskii

²

2007

Russ Phys J

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538.945The form of an electron paramagnetic resonance (EPR) in a thin paramagnetic film (λ/10, λ -London's depth of magnetic field penetration into superconductor) overlying the surface of an anisotropic superconductor is calculated taking into account the local magnetic field non-uniformity of an irregular Abrikosov's vortex lattice. It is shown that the form of EPR is noticeably varied with the degree of irregularity of the superconductor vortex lattice. It is suggested that an inclusion of this circumstance into consideration may essentially change the conclusions made on the lattice type and parameters of this superconductor, which are typically derived from the analysis of the EPR form.For the investigation of magnetic properties of high-temperature superconducting materials (HTSC) a wide use is made of the methods of magnetic resonance [1] and scanning of magnetic field on the surface of superconductor [2, 3], as well as of the experiments on muonic spin rotation [4]. Magnetic probing on the superconductor surface occupies a special place among the methods of superconductor studies. The probe typically used is a film of an organic compound of diphinil picryl hydrazyl (DPPH) in the case of EPR [5,6] or that of silicon oil in the case of nuclear magnetic resonance (NMR) [7]. In both cases, an examination is made of the temperature dependence of non-uniform linewidth of magnetic resonance under transition of a specimen into either non-supeconducting state or into vortex state in the case of the external uniform field sweeping. These experiments provide an estimation of the depth of magnetic field penetration into superconductor, λ. When the EPR-and NMR-probes were thin films (≤1000 Å) of controllable thickness, then it was possible to obtain more detailed information on superconductor parameters from the analysis of the magnetic resonance line shapes.This study presents the results of calculations of the shapes of lines of magnetic resonance in a thin magnetic field of a calibrated thickness (≈0.1 λ), coated onto the surface of an anisotropic superconductor. It is well known that an Abrikosov vortex lattice is formed in HTSC in an external magnetic field Н (Н с1 < H < H c2 , H c1 , H c2 are the first and second critical fields). However, the distribution of local magnetic field has so far been calculated for either regular vortex lattices [8 -10] or for the case of complete chaos in the distribution of Abrikosov's vortices -random non-correlated distribution of vortices [11], with no signs of a regular vortex lattice. Nonetheless, the case of a irregular vortex lattice is quite common. This can be presented as a lattice of vortices in which every i-th vortex is located not exactly in the node of a regular lattice but rather displaced by a certain arbitrary vector a i from its regular position in the lattice, provided that a i << L (L -average spacing between the vortices). These displacements a i can result both from vortex pinning and from quite slow thermal vibrations of the vortex lattice. It is this very ...

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Distribution of a local magnetic field in superconductors with an uncorrelated random lattice of abrikosov vortices

Cited by 5 publications

References 7 publications

Vortex lattice disorder inYBa2Cu3O7−δprobed using
Saadaoui
¹
,
MacFarlane
²
,
Salman
³

et al. 2009
Phys. Rev. B
11
1
3
0
View full text Add to dashboard Cite

Vortex lattice disorder inYBa2Cu3O7−δprobed using
Saadaoui
¹
,
MacFarlane
²
,
Salman
³

et al. 2009
Phys. Rev. B
11
1
3
0
View full text Add to dashboard Cite

Vortex lattice disorder in YBCO probed using Beta-NMR

Shape of a magnetic resonance line in a thin film on the surface of anisotropic superconductor with irregularly distributed Abrikosov’s vortices

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Distribution of a local magnetic field in superconductors with an uncorrelated random lattice of abrikosov vortices

Cited by 5 publications

References 7 publications

Vortex lattice disorder inYBa2Cu3O7−δprobed usingSaadaoui1, MacFarlane2, Salman3 et al. 2009Phys. Rev. B11130View full textAdd to dashboardCite

Vortex lattice disorder inYBa2Cu3O7−δprobed usingSaadaoui1, MacFarlane2, Salman3 et al. 2009Phys. Rev. B11130View full textAdd to dashboardCite

Vortex lattice disorder in YBCO probed using Beta-NMR

Shape of a magnetic resonance line in a thin film on the surface of anisotropic superconductor with irregularly distributed Abrikosov’s vortices

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Product

Resources

About

Vortex lattice disorder inYBa2Cu3O7−δprobed using
Saadaoui
¹
,
MacFarlane
²
,
Salman
³

et al. 2009
Phys. Rev. B
11
1
3
0
View full text Add to dashboard Cite

Vortex lattice disorder inYBa2Cu3O7−δprobed using
Saadaoui
¹
,
MacFarlane
²
,
Salman
³

et al. 2009
Phys. Rev. B
11
1
3
0
View full text Add to dashboard Cite