Magneto-Optical Investigation of Superconducting Materials

Polyanskii, Anatolii; Beilin, V.; Feldmann, M.; Roth, M.; Hellstrom, E. E.; Larbalestier, D. C.

doi:10.1007/978-94-007-1007-8_3

Cited by 8 publications

(10 citation statements)

References 8 publications

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“…Magneto-optical imaging is a method of visualization of magnetic flux, and full details of the technique are available elsewhere. 46,47 In short, magneto-optical imaging of thin HTS films reveals where magnetic flux is entering the superconductor, and this flux entrance is extremely sensitive to the ratio of intergrain to intragrain critical current density, J c gb /J c g . 15,48,49 The magnetooptical image of the PLD-grown film ( Fig.…”

Section: Electromagnetic Propertiesmentioning

confidence: 99%

A Review of the Influence of Grain Boundary Geometry on the Electromagnetic Properties of Polycrystalline YBa₂Cu₃O_7−x Films

Holesinger

Feenstra

Larbalestier

2008

Journal of the American Ceramic Society

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Shortly after the discovery of high‐temperature superconducting (HTS) materials in the late 1980s, it was revealed that grain boundaries in these complex oxides are strong barriers to current flow. This fact has remained one of the most significant challenges to a viable HTS conductor, and necessitated the development of technologies capable of producing biaxially textured substrates in long lengths. Multiple studies have reported that the critical current density (Jc) across grain boundaries in the perovskite‐like superconductor YBa2Cu3O7−x (YBCO) falls off exponentially below the intragrain Jc beyond a critical misorientation angle θc of only ≈2°–3°. Here we review our recent work demonstrating that certain grain boundary geometries permit significant enhancements of Jc well beyond the conventional Jc(θ) limit, and also that the grain boundary structure in YBCO films is tied closely to the films' deposition technique. Pulsed laser deposition, a physical vapor deposition technique, results in a columnar grain structure and planar grain boundaries that exhibit the typical Jc(θ) dependence. Ex situ growth processes, where the YBCO film is converted from a previously deposited precursor, can result in laminar grain growth with highly meandered grain boundaries. These latter grain boundary structures are directly correlated to greatly improved Jc values over a wide range of applied magnetic fields. Consequently, very high Jc values are possible in polycrystalline HTS wire even when significant misorientations between grains are present.

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Section: Electromagnetic Propertiesmentioning

confidence: 99%

A Review of the Influence of Grain Boundary Geometry on the Electromagnetic Properties of Polycrystalline YBa₂Cu₃O_7−x Films

Holesinger

Feenstra

Larbalestier

2008

Journal of the American Ceramic Society

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“…Highsensitivity and high-field homogeneity across the sample is maintained within the solenoid in the field range 0-200 Oe. We employ the conventional MOI [18] as well as the differential magnetooptical (DMO) imaging technique [19,20] to image the changes in local vortex density. A schematic diagram and details of our MOI setup have been presented elsewhere [20].…”

Section: Methodsmentioning

confidence: 99%

“…where A is the area over which averaging is performed and the local field B z (x, y) is determined from conventional MOI (without DMO) [18,21]. M(H) for the whole sample corresponds to A (A is the entire sample area), while the local M(H) for * corresponds to averaging over a region around the location marked with * in figure 1 with area A = 25 µm 2 .…”

Section: Location Of Jump In B Z At Low H With Respect To the Vortex mentioning

confidence: 99%

Visualizing a dilute vortex liquid to solid phase transition in a Bi₂Sr₂CaCu₂O₈single crystal

et al. 2012

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“…The presence of a nonzero magnetic induction, for example, due to the presence of magnetized grains in the rock sample, results in a rotation of the magnetization of the garnet, out of the film plane. While the in-plane component of the film's magnetization does not rotate the polarization angle of the light [Polyanskii et al, 2004], the component of the magnetization parallel to the propagation direction of the light results in a Faraday rotation…”

Section: Magneto-optical Imagingmentioning

confidence: 99%

“…The Faraday angle of rotation a F is proportional to the Verdet constant of the MO material (V) and its thickness d, and depends on the magnetic field components perpendicular (B ? ) and parallel to the film (B k ) [Polyanskii et al, 2004]. B k is the anisotropy field of the MO film.…”

Section: Magneto-optical Imagingmentioning

confidence: 99%

Advances in magneto‐optical imaging applied to rock magnetism and paleomagnetism

Uehara

Beek

Gattacceca

et al. 2010

Geochem Geophys Geosyst

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[1] We present results of the magneto-optical imaging technique applied to rock samples. This technique measures the magnetic flux threading a magneto-optically active film, which rotates the polarization direction of transmitted light (Faraday rotation) and is directly placed on the sample. Through the analyzer of a reflected light microscope, the vertical component of the surface magnetic field of the sample is observed and can be quantified through a specific calibration procedure. Owing to the thin magneto-optically active film (5 mm) and the small sample-to-film distance (∼1 mm), stray fields produced by magnetic grains in rocks carrying saturation isothermal remanent magnetization are successfully imaged with a spatial resolution of 10 mm. We can also image the surface field distribution of rocks carrying natural remanent magnetizations by modulating the analyzer angle. In addition to its high spatial resolution, this technique offers a direct comparison between magnetic and reflected light images. Therefore, this new technique appears to be a powerful tool to map and identify the carriers of magnetic remanence in rock samples.

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Magneto-Optical Investigation of Superconducting Materials

Cited by 8 publications

References 8 publications

A Review of the Influence of Grain Boundary Geometry on the Electromagnetic Properties of Polycrystalline YBa₂Cu₃O_7−x Films

A Review of the Influence of Grain Boundary Geometry on the Electromagnetic Properties of Polycrystalline YBa₂Cu₃O_7−x Films

Visualizing a dilute vortex liquid to solid phase transition in a Bi₂Sr₂CaCu₂O₈single crystal

Advances in magneto‐optical imaging applied to rock magnetism and paleomagnetism

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Magneto-Optical Investigation of Superconducting Materials

Cited by 8 publications

References 8 publications

A Review of the Influence of Grain Boundary Geometry on the Electromagnetic Properties of Polycrystalline YBa2Cu3O7−x Films

A Review of the Influence of Grain Boundary Geometry on the Electromagnetic Properties of Polycrystalline YBa2Cu3O7−x Films

Visualizing a dilute vortex liquid to solid phase transition in a Bi2Sr2CaCu2O8single crystal

Advances in magneto‐optical imaging applied to rock magnetism and paleomagnetism

Contact Info

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Resources

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A Review of the Influence of Grain Boundary Geometry on the Electromagnetic Properties of Polycrystalline YBa₂Cu₃O_7−x Films

A Review of the Influence of Grain Boundary Geometry on the Electromagnetic Properties of Polycrystalline YBa₂Cu₃O_7−x Films

Visualizing a dilute vortex liquid to solid phase transition in a Bi₂Sr₂CaCu₂O₈single crystal