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Mazilu, A.; Safar, H.; López, D.; Kwok, W. K.; Crabtree, G. W.; Guptasarma, P.; Hinks, D.G.

doi:10.1103/physrevb.58.r8913

Cited by 19 publications

(15 citation statements)

References 13 publications

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“…The mechanism responsible for this may be related to the so-called Bean-Livingston ͑BL͒ or surface barriers, 9 whose importance in the magnetic and electric behavior of HTCS has been experimentally addressed during the last years. [22][23][24][25][26][27][28] The physical origin of these barriers lies on two contributions: on one hand, the vortex-antivortex ͑mirror image outside the sample͒ interaction, which results in attractive force to the surface ͑barrier for flux entry͒. On the other hand, there is the repulsive Lorentz force on the vortex caused by shielding supercurrents in presence of applied magnetic field ͑barrier for flux escape͒.…”

Section: Fig 4 Superconducting Transitions Of Sample Ybcomentioning

confidence: 99%

Interface barriers for flux motion in high-temperature superconducting superlattices

et al. 2004

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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...

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Section: Fig 4 Superconducting Transitions Of Sample Ybcomentioning

confidence: 99%

Interface barriers for flux motion in high-temperature superconducting superlattices

et al. 2004

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“…It turns out later that this was not due to the sample quality or experimental setup but due to the surface barrier effect [61], which short-cuts the current path via the sample edges [19,21,22,62]. In order to avoid this effect, the Corbino disk method is introduced [23,24,46,[63][64][65][66].…”

Section: Corbino Disk Methodsmentioning

confidence: 99%

“…Since, most of experimental data so far available in the literature are obtained by the strip geometry with four terminal method, the resistivity of Bi 2 Sr 2 CaCu 2 O 8Cd deserves reconsideration. One should be careful to read experimental data so far available, because even data obtained by the Corbino disk are not always consistent [23,24,46,63,64].…”

Section: Corbino Disk Methodsmentioning

confidence: 99%

“…For dynamical measurements in small intrinsic junctions, conventional transport measurements have been carried out. We especially use the Corbino disk arrangement for the resistivity measurement in order to exclude the surface pinning effect [18,19] as well as possibly the geometrical barrier effect [20], which causes non-linear resistivity in the vortex liquid state [21][22][23][24].…”

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Vortex states in high-T_c superconductors and superconductivity in modern nano-science and engineering

Kadowaki

2005

Science and Technology of Advanced Materials

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A brief review is given on the recent development of the vortex engineering research in our group with special emphasis on the geometrical confinement of vortices into micron-size of samples. We show that the static as well as dynamical nature of vortices is strongly affected by the geometrical constraints, which can be manipulated by the recent nano-technology engineering artificially. One of the spectacular phenomena in this context is a formation of self-organized vortex structures occuring both in static and dynamic manners. The static behaviors have been studied by the scanning SQUID microscope technique and the dynamical behaviors are mostly done in transport measurements. Some technical development of these methods is also discussed. We stress that a common generic concept here is the confinement in nano-scale superconducting systems by the existing surfaces (boundaries), which plays an essential role for the phenomena. Some typical examples are shown, such as results on the vortex arrangement in micron size superconducting disks, a formation of the giant vortex state in such a particular case and the dynamical effects of vortices, especially in the case of Josephson vortices confined in an intrinsic Josephson junction in micron size single crystal Bi 2 Sr 2 CaCu 2 O 8Cd , where the dynamical effect of the confinement provides rich linear and non-linear phenomena due to the excitation of Josephson plasma. Making use of Josephson plasma excitations, a generator operating at T (Hz) frequencies is proposed in this intrinsic Josephson junctions. These phenomena are expected to be all beneficial to potential applications. q

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“…5 Magneto-optical imaging of the vortex structure in high-T c Bi 2 Sr 2 CaCu 2 O 8+␦ ͑BSCCO͒ has shown similar results. 23 However, some work on amorphous Mo x Ge 1−x films and BSCCO single crystals with different contact geometries showed contrary results 24,25 by demonstrating that the edge effect is not important for static or dynamics vortex properties. Since there are so many different assumptions for the mechanism of this phenomenon, we aim to find out a possible way to clarify its origin.…”

Section: Introductionmentioning

confidence: 98%

Filamentary flow of vortices in aBi2Sr2Ca1Cu2O8<

et al. 2010

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Using microbridge technique, we have studied the vortex dynamics in a very low-temperature region ͑i.e., T / T c → 0͒ of the B-T phase diagram of Bi 2 Sr 2 Ca 1 Cu 2 O 8+␦ single crystal. We distinguish two types of vortex dynamics near the depinning threshold depending on the magnitude of the vortex-vortex interactions. For 0.01Յ 0 H Ͻ 1 T, we show that current-voltage ͑I-V͒ characteristics are strongly dependent on the history of magnetic field and current cycling. The sharp peak, so-called "peak effect," observed in 0 H-I c curve is due to a metastable state that can be removed after current cycling. At low field, I-V curves show steps that would be clearly related to "fingerprint phenomenon" since the relationship R d = dV / dI exists. This can be attributed to vortices flow through uncorrelated channels for the highly defective lattice. Indeed, as field sufficiently increases, these peaks merge to make broader ones indicating a crossover from filamentary strings to braid riverlike in which vortex-vortex interactions becomes significant. As confirmed by the discontinuity in the critical exponent value ␤ determined in the vicinity of the threshold current using the power-law scaling V ϳ͑I − I c ͒ ␤ with a crossover from ␤ = 2.2 to ␤ = 1.2. The strong vortex correlation along the c axis has been clearly demonstrated using the dc-flux-transformer geometry for transport measurements that confirms the pseudo-two-dimensional ͑2D͒ behavior of the flux-line lattice. Our transport studies are in good agreement with simulations results of 2D elastic objects driven by repulsive interactions through a random pinning potential.

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Experimental comparison of the effect that bulk pinning and surface barriers have on vortex motion in the vortex liquid state ofBi2Sr2

Cited by 19 publications

References 13 publications

Interface barriers for flux motion in high-temperature superconducting superlattices

Interface barriers for flux motion in high-temperature superconducting superlattices

Vortex states in high-T_c superconductors and superconductivity in modern nano-science and engineering

Filamentary flow of vortices in aBi2Sr2Ca1Cu2O8<

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Experimental comparison of the effect that bulk pinning and surface barriers have on vortex motion in the vortex liquid state ofBi2Sr2

Cited by 19 publications

References 13 publications

Interface barriers for flux motion in high-temperature superconducting superlattices

Interface barriers for flux motion in high-temperature superconducting superlattices

Vortex states in high-Tc superconductors and superconductivity in modern nano-science and engineering

Filamentary flow of vortices in aBi2Sr2Ca1Cu2O8<

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Vortex states in high-T_c superconductors and superconductivity in modern nano-science and engineering