Weak links and dc SQUIDS on artificial nonsymmetric grain boundaries in YBa2Cu3O7−δ

Ivanov, Z. G.; Nilsson, Per-Åke; Winkler, Dag; Alarco, José A.; Claeson, T.; Stepantsov, E. A.; Tzalenchuk, Alexander

doi:10.1063/1.105783

Cited by 242 publications

(76 citation statements)

References 9 publications

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“…In thin-film ͓001͔ tilt bicrys- 11,12 Since the magnitude of flux penetration at a GB increases as J cb /J cg decreases, 4 qualitative comparisons of the current-carrying capability of the GBs are possible. Accordingly, we estimated the relative magnitude of flux penetration by measuring the MO image intensity at more than 60 of the GBs in Fig.…”

mentioning

confidence: 99%

Influence of nickel substrate grain structure on YBa2Cu3O7−x supercurrent connectivity in deformation-textured coated conductors

Reeves

Polyanskii

Kozlowski

et al. 2000

Applied Physics Letters

109

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Coupled magneto-optical imaging and local misorientation angle mapping have been used to demonstrate the percolative nature of supercurrent flow in YBa 2 Cu 3 O 7Ϫx ͑YBCO͒ coated conductors grown on deformation-textured Ni substrates. Barriers to current flow occur at many YBCO grain boundaries ͑GBs͒ which have propagated through the buffer layers from the underlying Ni substrate, and all Ni GBs with misorientation angles Ͼ4°initiate percolative current flow. This type of current barrier is characteristic of the conductor form and has been found to exist in samples with J c (0 T,77 K) values Ͼ2 MA/cm 2 . Sharpening of the local substrate texture or improving in low-angle GB properties should lead to higher J c values. © 2000 American Institute of Physics. ͓S0003-6951͑00͒00341-7͔High critical current density (J c ) conductors capable of operating in fields of several tesla at liquid-nitrogen temperature are critical to large-scale applications of hightemperature superconductors. Coated conductors ͑CCs͒ with biaxially textured YBa 2 Cu 3 O x ͑YBCO͒ respond to this need. [1][2][3] One widely employed approach today uses deformation texturing of a metal substrate, generally pure Ni, on which buffer layers and YBCO are grown. 1,2 Such architectures permit J c (0 T,77 K) values 1,2 Ͼ1 MA/cm 2 , but many samples have lower values. Here we couple magneto-optical imaging and local misorientation angle mapping to show that many such barriers to current flow occur at YBCO grain boundaries ͑GBs͒ which have propagated through the buffer layers from the Ni GBs in the underlying substrate. All Ni GBs with misorientation angles Ͼ4°were found to initiate percolative current flow. Since typical deformation-textured substrates have many GBs misoriented in the range of 5°-10°, this study shows that it will be very valuable for CC technology to further enhance substrate texture and/or to improve low-angle GB properties.Magneto-optical ͑MO͒ imaging, light microscopy, and backscattered electron Kikuchi pattern ͑BEKP͒ analysis of the local texture were conducted on a series of four CC samples grown on deformation-textured Ni substratres with in-plane and out-of-plane full width at half maxima of 6.6°-7.4°and 5.8°-8.7°, respectively, as measured by x-ray pole figures. The buffer and YBCO layers were deposited by pulsed-laser deposition ͑PLD͒ with architecture YBCO/CeO 2 /yttria-stabilized zirconia ͑YSZ͒/CeO 2 /Ni and thickness of 300-1200/100/500/100 nm for the respective oxide layers. The thickness of the YBCO layer varied from sample to sample without obvious differences in the properties measured by MO imaging and ac susceptibility. A 0.6-m-thick YBCO sample had a high transport J c (0 T,77 K) of 1.2 MA/cm 2 . The remaining samples were taken directly to other characterizations.A representative MO image of the granular fluxpenetration network obtained using standard imaging procedures 4,5 is shown in Fig. 1. This network is common to CCs with varying constructions from multiple sources. Among the variations are deformation-textured s...

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mentioning

confidence: 99%

Influence of nickel substrate grain structure on YBa2Cu3O7−x supercurrent connectivity in deformation-textured coated conductors

Reeves

Polyanskii

Kozlowski

et al. 2000

Applied Physics Letters

109

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“…1. In this figure, previously reported [6][7][8] angle, 0, between the grains. Qualitatively, the data for the thin film and bulk bicrystal grain boundaries is simila~each shows a sharp decrease in J. across the boundary as 0 increases.…”

Section: Introductionmentioning

confidence: 95%

“…The dependence of J. on field orientation was measured for one 90°[100] tilt boundary by rotating the field in the plane cf the boun&ry. The data from Ivanov [6], Heinig [7], and Todt [8] are all for nominal [00 1] tilt boundaries.…”

Section: Hexperimentalmentioning

confidence: 99%

The influence of vortex pinning and grain boundary structure on critical currents across grain boundaries in YBa/sub 2/Cu/sub 3/O/sub x/

Miller

Field

Kim

1999

IEEE Trans. Appl. Supercond.

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Section: Introductionmentioning

confidence: 99%

“…Bicrystals of SrTiO 3 and Yttrium Stabilized ZrO 2 have been used [1,2] giving the possibility to vary the induced weak link angle between 0 and 45 degrees. The dependence of the critical current density on this angle is reported [1,2]. A second way for the creation of bi-epitaxial Josephson junctions makes use of different in-plane orientations of YBa2Cu307_ d on top of structured multilayers [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Bi-epitaxial template grain boundaries with different in-plane angles on (100) MgO substrates

IJsselsteijn

Hilgenkamp

Eisenberg

et al. 1993

Journal of Alloys and Compounds

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Using laser ablation CeO 2 and YBa2Cu307. d layers have been deposited on (100) oriented MgO substrates for the creation of bi-epitaxial grain boundary weak links. X-Ray Diffraction measurements were used to measure the (in-plane) orientations of the layers. The CeO 2 layer has been structured using Ar ion beam etching or CaO lift off. Using these two structuring techniques it is possible to obtain two different grain boundary weak link angles: 18 and 27 degrees. Up till now only 45 degrees weak link angles have been reported in literature, using templates for the creation of these grain boundaries.

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Weak links and dc SQUIDS on artificial nonsymmetric grain boundaries in YBa2Cu3O7−δ

Cited by 242 publications

References 9 publications

Influence of nickel substrate grain structure on YBa2Cu3O7−x supercurrent connectivity in deformation-textured coated conductors

Influence of nickel substrate grain structure on YBa2Cu3O7−x supercurrent connectivity in deformation-textured coated conductors

The influence of vortex pinning and grain boundary structure on critical currents across grain boundaries in YBa/sub 2/Cu/sub 3/O/sub x/

Bi-epitaxial template grain boundaries with different in-plane angles on (100) MgO substrates

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