Anisotropic Vortex Plasticity in the Liquid State of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>YBa</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>O</mml:mi></mml:mrow><mml:mrow><mml:mn>7</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>: Evidence

Puig, T.; Obradors, X.

doi:10.1103/physrevlett.84.1571

Cited by 37 publications

(18 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4,6,10 It was suggested that H lcp was not modified by twin boundaries but this is an unexpected behavior because twin boundaries lead to a secondorder Bose-glass transition, 11 characterized by a cusp in the ''irreversibility line'' and in the vortex activation energy for magnetic-field orientations close to the c axis. 12,13 This behavior would be also inconsistent with a recent study of the influence on H lcp of linear defects created by ion irradiation. 8 That work showed that H lcp is pushed up while the Boseglass regime develops.…”

contrasting

confidence: 76%

“…13,14,22 Considering the fraction of vortices pinned at twin boundaries and that the pinning force only distorts the lattice in one direction, we can estimate the pinning energy per vortex as U tb ϭ1/2nl eff U p , where l eff is the effective length of the vortex pinned at the twin boundary and n is the fraction of vortices pinned at twin boundaries. An upwards shift of H lcp (0) encompasses a decrease of the elastic energy per vortex by the same amount as the increase of pinning energy per vortex at twin boundaries.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Anisotropy of the low-field critical point of the melting line of twinnedYBa2Cu3O
Figueras
¹
,
Puig
²
,
Obradors
³

et al. 2002
Phys. Rev. B
3
0
3
0
View full text Add to dashboard Cite

We demonstrate that the anisotropy of the low-field critical point (H lcp ) of the vortex lattice melting line in a twinned YBa 2 Cu 3 O 7Ϫ␦ single crystal follows the intrinsic anisotropic behavior of the melting line when the disordered phase is originated by point defects. When the vortices are pinned at twin boundaries an upwards shift of H lcp is observed. The contribution of twin boundary pinning has been found to match with the change in the vortex elastic energy barriers thus supporting the identification of the low-field phase as a disordered solid vortex phase where vortex pinning overcomes the vortex-vortex interaction.In clean superconducting crystals the vortices present a first-order transition from a liquid to an ordered solid state. This transition has been characterized by several authors by means of thermodynamic, 1 magnetic, 2 and transport 3 measurements. When some kind of disorder is introduced in the lattice, however, a complex behavior appears which is controlled by the balance between vortex-vortex interaction, the pinning energy with defects, and thermal activation. One important consequence of disorder is that the lattice melting line is actually bounded by an upper critical field H ucp and a low critical field H lcp where the transition becomes second order. The influence of random point defects, such as oxygen vacancies, 4 electron or proton irradiation, 5 planar defects such as twin boundaries, 6,7 and columnar defects generated by ion irradiation, 8 on the features of the magnetic phase diagram of YBa 2 Cu 3 O 7Ϫ␦ , has been widely investigated, however a coherent picture is still lacking. The nature of the transition among the liquid and solid vortex states below the low-field critical point remains still an open issue. 9 In particular, the anisotropy of H lcp and its dependence on the different types of defects are not known. The low critical field may be shifted by more than two orders of magnitude, when the crystal is irradiated with protons. 5 When point defects are created by electron irradiation, however, the low-field critical point remains insensible. The influence of twin boundaries remains also extremely puzzling. 4,6,10 It was suggested that H lcp was not modified by twin boundaries but this is an unexpected behavior because twin boundaries lead to a secondorder Bose-glass transition, 11 characterized by a cusp in the ''irreversibility line'' and in the vortex activation energy for magnetic-field orientations close to the c axis. 12,13 This behavior would be also inconsistent with a recent study of the influence on H lcp of linear defects created by ion irradiation. 8 That work showed that H lcp is pushed up while the Boseglass regime develops. It appears then a fundamental problem to determine the intrinsic anisotropy of the critical points and their interaction with planar defects behaving as correlated disorder. 14 In this paper we address these fundamental open questions for the low-field critical point. From anisotropic magnetoresistance measurements we determine the...

show abstract

contrasting

confidence: 76%

mentioning

confidence: 99%

Anisotropy of the low-field critical point of the melting line of twinnedYBa2Cu3O
Figueras
¹
,
Puig
²
,
Obradors
³

et al. 2002
Phys. Rev. B
3
0
3
0
View full text Add to dashboard Cite

show abstract

“…This situation is recently realized in electron and proton irradiated YBCO single crystal [6,7]. Most recently, although similar phenomenon was predicted in twinned melt-processed Nd-based superconductor [8], a partially entangled vortex state is proposed in melt-processed YBCO with second-phase addition [9]. The competition between the planar, such as TBs, and the quenched disorders such as second-phase, and 0 2 related defects might have dramatic consequence on the enhancement of J, and its optimization in melt-processed NEG material.…”

Section: Introductionsupporting

confidence: 61%

Flux pinning in melt-processed ternary (Nd-Eu-Gd) and Nd-based superconductors

Pradhan

Muralidhar

Feng

et al. 2001

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

We report on the flux pinning and optimization of melt-processed ternary (Nd-Eu-Gd)BatCu307., bulk materials using magnetization and magneto-transport (quasi-flux transformer technique) measurements. The highest flux pinning was observed for the optimal annealing condition, where twin planes act as correlated pinning in the presence of the optimal second-phase addition.The addition of Ag decreases low-field critical current density, whereas high-field behavior does not change drastically. The results were compared with NdBa2Cu307., single crystals that show various vortex states with increasing defect density. The melt-processed samples demonstrate very similar behavior to the single crystal. The interplay between the point defect and the twin planes resulting an entangled vortex liquid-state remains valid for both single crystals and melt-processed samples. Index Terms-flux pinning, critical current density, meltprocessed bulk materials, vortex phase-transition I. INTRODUCTIONELT-processed REB~zCU~O,.~ (RE = Nd, Eu, Gd, Y) superconductors are becoming promising materials for high temperature and high field power applications such as magnetic bearings, flywheel energy storage, and bulk magnets [1,2] due to their extremely high critical current density J, at 77K. Recently, a surprising enhancement in J, was recorded [3] in (Nd-EuGd)Ba2Cu307-8 (NEG) ternary melt-processed system and probably the value of J, may reach the required engineering value for power applications at 77K on further optimization. The flux dynamics in case of high pinning and their actual behavior in magnetic field are not known yet. It is essential to compare the physical properties of these bulk materials with single crystals to understand the underlying pinning mechanism for enhancement and optimization of J,.

show abstract

“…Following the 3D anisotropic model, the angular and field dependent activation energy U(,H,T) can be described by 18,19 U͑,H,T ͒ϭU 0 ͑ ,H͒ ͩ 1Ϫ…”

Section: ͑2͒mentioning

confidence: 99%

Interface barriers for flux motion in high-temperature superconducting superlattices

et al. 2004

View full text Add to dashboard Cite

We study angular dependent magnetoresistance in the vortex-liquid phase of epitaxial YBa 2 Cu 3 O 7 thin films and YBa 2 Cu 3 O 7 /PrBa 2 Cu 3 O 7 superlattices. Superlattices were grown with different PrBa 2 Cu 3 O 7 thickness in order to tune coupling between YBa 2 Cu 3 O 7 layers. While dissipation of single film and coupled superlattices is scaled with the anisotropic three-dimensional model in the whole angular range, decoupling through PrBa 2 Cu 3 O 7 spacer breaks down the scaling and yields strong reduction of the dissipation when the magnetic fields are applied up to Ϯ20°around the interface direction. Bean-Livingston barriers at the interface are the mechanism which governs this behavior. DOI: 10.1103/PhysRevB.69.134505 PACS number͑s͒: 74.72.Bk, 74.78.Bz, 74.78.Fk, 74.25.Fy Vortex matter in high-temperature oxide superconductors ͑HTCS͒ has been extensively investigated during the last years. The mixed state properties of HTCS are governed by the interplay between the elastic properties of the vortex lattice, thermal fluctuations, and the presence of different kinds of disorder, yielding a complicated phase diagram which shows a rich variety of phenomena.1,2 The intrinsically anisotropic structure of these oxide superconductors induces anisotropic magnetotransport properties. At magnetic fields H applied parallel to Cu-O planes the dissipation is reduced with respect to the situation where magnetic fields are perpendicular to them, due to the so-called intrinsic pinning. Moreover, it has been recently shown that this anisotropic structure stabilizes a vortex smectic phase when the vortex lattice matches the periodic layered structure. 4 In this context, superconducting/insulator YBa 2 Cu 3 O 7 /PrBa 2 Cu 3 O 7 ͑YBCO/PBCO͒ superlattices are interesting structures to artificially modify the anisotropic behavior of this HTSC.5 This artificial manipulation yields a number of phenomena related to low dimensionality and vanishing coupling between YBCO layers, 6 vortex phase coherence, 7 dissipation anisotropy, 8 etc. In this paper, we show that vortex pinning is enhanced in fully decoupled YBCO layers, when magnetic field is applied parallel to YBCO/PBCO interfaces. We investigate the physical origin of this behavior by studying the angular dependent dissipation in the liquid state of c-axis oriented YBCO/PBCO superlattices. We discuss on the interplay between intrinsic and interface pinning, and we point to surfacelike 9 barriers at the YBCO/PBCO interface as a probable origin for the observed behavior.Epitaxial c-axis oriented YBCO/PBCO superlattices and YBCO single film were grown on ͑100͒ SrTiO 3 substrates using a high-pressure sputtering system, with stoichiometric PBCO and YBCO targets. Chamber pressure was 3.4 mbar of pure oxygen during deposition, and substrate temperature was held at 900°C. Deposition rate was as low as 0.013 nm s Ϫ1 , which accurately allows controlling layers thickness. The structural characterization was made by both low-and high-angle x-Ray-diffraction technique and transmis...

show abstract

Anisotropic Vortex Plasticity in the Liquid State ofYBa2Cu3O7: Evidence

Cited by 37 publications

References 24 publications

Anisotropy of the low-field critical point of the melting line of twinnedYBa2Cu3O
Figueras
¹
,
Puig
²
,
Obradors
³

et al. 2002
Phys. Rev. B
3
0
3
0
View full text Add to dashboard Cite

Anisotropy of the low-field critical point of the melting line of twinnedYBa2Cu3O
Figueras
¹
,
Puig
²
,
Obradors
³

et al. 2002
Phys. Rev. B
3
0
3
0
View full text Add to dashboard Cite

Flux pinning in melt-processed ternary (Nd-Eu-Gd) and Nd-based superconductors

Interface barriers for flux motion in high-temperature superconducting superlattices

Contact Info

Product

Resources

About

Anisotropic Vortex Plasticity in the Liquid State ofYBa2Cu3O7: Evidence

Cited by 37 publications

References 24 publications

Anisotropy of the low-field critical point of the melting line of twinnedYBa2Cu3OFigueras1, Puig2, Obradors3 et al. 2002Phys. Rev. B3030View full textAdd to dashboardCite

Anisotropy of the low-field critical point of the melting line of twinnedYBa2Cu3OFigueras1, Puig2, Obradors3 et al. 2002Phys. Rev. B3030View full textAdd to dashboardCite

Flux pinning in melt-processed ternary (Nd-Eu-Gd) and Nd-based superconductors

Interface barriers for flux motion in high-temperature superconducting superlattices

Contact Info

Product

Resources

About

Anisotropy of the low-field critical point of the melting line of twinnedYBa2Cu3O
Figueras
¹
,
Puig
²
,
Obradors
³

et al. 2002
Phys. Rev. B
3
0
3
0
View full text Add to dashboard Cite

Anisotropy of the low-field critical point of the melting line of twinnedYBa2Cu3O
Figueras
¹
,
Puig
²
,
Obradors
³

et al. 2002
Phys. Rev. B
3
0
3
0
View full text Add to dashboard Cite