Influence of tilted geometries on critical current in superconducting thin films

Maiorov, B.; Gibbons, Brady J.; Kreiskott, Sascha; Matias, Vladimir; Jia, Q. X.; Holesinger, T. G.; Civale, L.

doi:10.1109/tasc.2005.847659

Cited by 25 publications

(18 citation statements)

References 15 publications

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“…Therefore, such a measurement technique appears to differ from the transport measurements of J c ͑H , , ͒, because the angle between the current direction and the dc field rotation plane is indefinite. However, taking into account that J c ͑H , ͒ dependences for = 0 and 90°are quite similar to each other and they may differ only a bit quantitatively, 14 the J c ͑H , ͒ dependences obtained by the inductive technique are expected to describe correctly the principal features of the dependence of J c , in particular those connected with parallel vortice penetration into a thin film.…”

Section: B Measurement Techniques Of the Critical Current Densitymentioning

confidence: 88%

Supercurrent transport inYBa2Cu3O7−δepitaxial thin films in a dc magnetic field

et al. 2006

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Magnetic field and angle dependences of the critical current density J c ͑H , ͒ in epitaxial c-oriented YBa 2 Cu 3 O 7−␦ thin films are measured by the four-probe transport current technique, low-frequency ac magnetic susceptibility, and superconducting quantum interference device magnetometry. The films under study are deposited by off-axis dc magnetron sputtering onto r-cut sapphire substrates buffered with a CeO 2 layer. A consistent model of vortex pining and supercurrent limitation is developed and discussed. Rows of growthinduced out-of-plane edge dislocations forming low-angle boundaries ͑LAB's͒ are shown to play a key role in achievement of the highest critical current density J c ജ 2 ϫ 10 6 A/cm 2 at 77 K. The model takes into account the transparency of LAB's for supercurrent as well as the pinning of vortex lattice on a network of LAB's. Principal statistical parameters of the film defect structure, such as the domain size distribution and mean misorientation angle, are extracted from J c ͑H͒ curves measured in a magnetic field H applied parallel to the c axis and from x-ray diffraction data. An evolution of angle dependences J c ͑͒ with H is shown to be consistent with the model supposing dominant pinning on edge dislocations. Strongly pinned vortices parallel to the c axis appear to exist in tilted low magnetic fields up to a characteristic threshold field, below which the magnetic induction within the film obeys a simple relation B = H cos . This feature is shown to explain the absence of the expected maximum of J c ͑͒ at H ʈ c in a low applied field. A peak of J c ͑H͒ and an angular hysteresis of J c ͑͒, which have been observed in an intermediate-field range, are discussed in terms of film thickness, surface quality, and orientation of the applied field. The observed effects are found to be consistent with the developed model. DOI: 10.1103/PhysRevB.73.054508 PACS number͑s͒: 74.25.Sv, 74.72.Bk, 74.78.Bz lated disorder ͑e.g., by random pointlike pins͒, the J c ͑H , ͒ dependence is determined by a single parameter H͑cos 2 + 2 sin 2 ͒ 1/2 , 12,13 where = ͱ m ab / m c is the anisotropy parameter, =1/5-1/7 for YBCO. For the monotonic decreasing J c ͑H , =0͒ dependence the scaling naturally yields the J c ͑H = const, ͒ dependence with a minimum at = 0 and a maximum at = /2.Moreover, a maximum of the J c ͑H , ͒ dependence at H ʈ c was shown ͑e.g., Ref. 6͒ to be absent for YBCO films. Ironically, many researchers considered this observation to be strong evidence for the absence of out-of-plane linear pins or their ineffectiveness for vortex pinning in epitaxial films. In a contrast, recently Maiorov et al. have observed the J c ͑H , ͒ peak at H ʈ c. 14 The maximum does exist and tends to shift PHYSICAL REVIEW B 73, 054508 ͑2006͒

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Section: B Measurement Techniques Of the Critical Current Densitymentioning

confidence: 88%

Supercurrent transport inYBa2Cu3O7−δepitaxial thin films in a dc magnetic field

et al. 2006

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“…represents the GL anisotropy and γ m = (m c /m ab ) ½ the electronic mass anisotropy [18].The scaling works best for higher fields, firstly because at low fields the applied field and the flux lines are not necessarily parallel to each other [19] (a prerequisite for anisotropic GL scaling), secondly because the J c range is larger, leading therefore to a higher accuracy of the scaling. The scaling procedure can provide information about different pinning regimes if γ m is known [20].…”

Section: Discussionmentioning

confidence: 99%

$J_{\rm c}$ Scaling and Anisotropies in Co-Doped Ba-122 Thin Films

Hänisch

Iida

Haindl

et al. 2011

IEEE Trans. Appl. Supercond.

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We have successfully grown epitaxial, superconducting films of Ba(Fe 1-x Co x ) 2 As 2 (Ba-122)with x ~ 0.1. The films grow without observable correlated defects parallel to the c-axis, as confirmed by TEM. This is also reflected in the absence of a caxis peak in J c (θ). In contrast to cuprate high-T c superconductors such as YBa 2 Cu 3 O 7-δ δ δ δ or even Bi 2 Sr 2 Ca 2 Cu 3 O 10-δ δ δ δ , the pnictides show a rather low anisotropic behavior in their J c (θ) behavior as well as in their upper critical fields, H c2 . As a multiband superconductor, Ba-122 exhibits a temperature dependent electronic mass anisotropy.

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“…1. The maximum critical current of the REBCO conductor does not appear at due to the tilted -axis [2], [3]. In the present study, the effect of the tilted -axis was not considered.…”

Section: Development Of Layer-wound Rebco Coilmentioning

confidence: 85%

REBCO Layer-Wound Coil Tests Under Electromagnetic Forces in an External Magnetic Field of up to 17.2 T

Matsumoto

Choi

Toko

et al. 2012

IEEE Trans. Appl. Supercond.

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A nuclear magnetic resonance (NMR) system using a high-temperature superconducting (HTS) magnet and a probe with an HTS radio frequency coil is currently under development. The HTS NMR magnet is expected to reduce the volume occupied by the magnet and to encourage users to install higher field NMR systems. RE-Ba-Cu-O-coated (REBCO-coated) conductors offer the advantages of a higher critical current density than low-temperature superconductors in magnetic fields above 10 T as well as tolerance to high tensile stress. Both of these factors are expected to lead to a reduction in the volume of the magnet. Four REBCO layer-wound test coils were fabricated in order to investigate their properties under electromagnetic forces in an external magnetic field of up to 17. 2 T. The REBCO coils with a practical inner diameter were successfully operated under electromagnetic forces of over 200 MPa in high magnetic fields.

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Influence of tilted geometries on critical current in superconducting thin films

Cited by 25 publications

References 15 publications

Supercurrent transport inYBa2Cu3O7−δepitaxial thin films in a dc magnetic field

Supercurrent transport inYBa2Cu3O7−δepitaxial thin films in a dc magnetic field

$J_{\rm c}$ Scaling and Anisotropies in Co-Doped Ba-122 Thin Films

REBCO Layer-Wound Coil Tests Under Electromagnetic Forces in an External Magnetic Field of up to 17.2 T

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