Scanning Hall-probe microscopy for site-specific observation of microstructure in superconducting wires and tapes for the clarification of their performance bottlenecks

Higashikawa, Kohei; Inoue, Masayoshi; Ye, Shujun; Matsumoto, Akiyoshi; Kumakura, Hiroaki; Yoshida, Ryuji; Kato, Takumi; Machi, T.; Ibi, A.; Izumi, Teruo; Kiss, Takanobu

doi:10.1088/1361-6668/ab89ef

Cited by 12 publications

(3 citation statements)

References 52 publications

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“…Quantitative vortex images can be used to investigate the nature of superconductivity in a host of materials, such as to study the impact of magnetism on superconductivity in hybrid-ferromagnetic superconductors for example in RbEuFe 4 As 4 [43], or the behaviour of nanostructured superconductors in lead and YBCO [44]. SHPM has also been used to study ferromagnetic materials for applications such as magnetic data storage devices, permalloy disks, the nature of current flows in high temperature superconducting tapes and magnetic domain structures [45][46][47][48]. SHPM is a good example of a Hall probe application requiring more stringent criteria for the material selection.…”

Section: Current Hall Sensor Applications and Directionsmentioning

confidence: 99%

Frontiers of graphene-based Hall-effect sensors

Collomb

Li²,

Bending³

2021

J. Phys.: Condens. Matter

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Hall sensors have become one of the most used magnetic sensors in recent decades, performing the vital function of providing a magnetic sense that is naturally absent in humans. Various electronic applications have evolved from circuit-integrated Hall sensors due to their low cost, simple linear magnetic field response, ability to operate in a large magnetic field range, high magnetic sensitivity and low electronic noise, in addition to many other advantages. Recent developments in the fabrication and performance of graphene Hall devices promise to open up the realm of Hall sensor applications by not only widening the horizon of current uses through performance improvements, but also driving Hall sensor electronics into entirely new areas. In this review paper we describe the evolution from the traditional selection of Hall device materials to graphene Hall devices, and explore the various applications enabled by them. This includes a summary of the selection of materials and architectures for contemporary micro-to nanoscale Hall sensors. We then turn our attention to introducing graphene and its remarkable physical properties and explore how this impacts the magnetic sensitivity and electronic noise of graphene-based Hall sensors. We summarise the current state-of-the art of research into graphene Hall probes, demonstrating their record-breaking performance. Building on this, we explore the various new application areas graphene Hall sensors are pioneering such as magnetic imaging and non-destructive testing. Finally, we look at recent encouraging results showing that graphene Hall sensors have plenty of room to improve, before then discussing future prospects for industry-level scalable fabrication.

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Section: Current Hall Sensor Applications and Directionsmentioning

confidence: 99%

Frontiers of graphene-based Hall-effect sensors

Collomb

Li²,

Bending³

2021

J. Phys.: Condens. Matter

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“…Indeed, due to the fabrication process used to deposit and grow the REBCO film on CCs, imperfections in the microstructure, such as grain boundaries associated with misoriented grains, can affect the current percolation within the HTS layer. , As a result, the distribution of the supercurrents along the length and width of the conductor becomes inhomogeneous, resulting in local variations of the critical current ( I c ) up to ±10% . If the applied current is near the average I c of the conductor, zones with lower I c can locally quench .…”

Section: Introductionmentioning

confidence: 99%

Chemical Solution Deposition of Insulating Yttria Nanolayers as Current Flow Diverter in Superconducting GdBa₂Cu₃O_7−δ Coated Conductors

et al. 2022

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The primary benefit of a metallic stabilization/shunt in high temperature superconductor (HTS) coated conductors (CCs) is to prevent joule heating damage by providing an alternative path for the current flow during the HTS normal state transition (i.e., quench). However, the shunt presence in combination with unavoidable fluctuations in the critical current ( I c ) of the HTS film can develop a localized quench along the CC’s length if the operational current is kept close to I c . This scenario, also known as the hot-spot regime, can lead to the rupture of the CC if the local quench does not propagate fast enough. The current flow diverter (CFD) is the CC architecture concept that has proven to increase the conductor’s robustness against a hot-spot regime by simply boosting the quench velocity in the CC, which avoids the shunt compromise in some applications. This work investigates a practical manufacturing route for incorporating the CFD architecture in a reel-to-reel system via the preparation of yttrium oxide (Y 2 O 3 ) as an insulating thin nanolayer (∼100 nm) on top of a GdBa 2 Cu 3 O 7 (GdBCO) superconductor. Chemical solution deposition (CSD) using ink jet printing (IJP) is shown to be a suitable manufacturing approach. Two sequences of the experimental steps have been investigated, where oxygenation of the GdBCO layer is performed after or before the solution deposition and the Y 2 O 3 nanolayer thermal treatment formation step. A correlated analysis of the microstructure, in situ oxygenation kinetics, and superconducting properties of the Ag/Y 2 O 3 /GdBCO trilayer processed under different conditions shows that a new customized functional CC can be prepared. The successful achievement of the CFD effect in the case of the preoxygenated customized CC was confirmed by measuring the current transfer length, thus demonstrating the effectiveness of the CSD-IJP as a processing method.

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“…Hot spots originating from inhomogeneity have been identified in some cases as the limitation of high-field magnet performance [30,[53][54][55], and contributed to the conservative design concept, substantially limiting the exploitation of the conductor transport capability [56]. Delivering the information about the I c (x) distribution together with the supplied tape has become a common practice thanks to the development of scanning techniques [37,[57][58][59] suitable for long-length reelto-reel inspection [60][61][62][63].…”

Section: Introductionmentioning

confidence: 99%

Stability of DC transport in HTS conductor with local critical current reduction

Gömöry

Šouc

2021

Supercond. Sci. Technol.

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A common feature of commercially available conductors based on high-temperature superconducting compounds is the fluctuation of critical current along the length. Fortunately, the practice adopted by manufacturers nowadays is to supply the detailed I c(x) data with the conductor. Compared to knowing just the average of critical current, this should also allow a much better prediction of the conductor performance. Statistical methods are suitable for this purpose in the case when the fluctuations are regular at the low end of critical current distribution. However, a different approach is necessary at the presence of ‘weak spots’ that drop out of any statistics. Because of the strong nonlinearity of the current–voltage curve, such a location could transform into a ‘hot spot’ at transporting direct current (DC), with an abrupt increase of temperature endangering the conductor operation. We present a set of analytical formulas including the prediction of the maximum DC that could be carried sustainably before the thermal runaway appears. It is necessary to know the cooling conditions as well as the properties of the conductor constituents and their architecture. A formula for the voltage appearing on a weak spot, and its dependence on the DC, is also proposed. For this purpose the result of previous theoretical work has been slightly modified after comparing it with numerical iterative computations and finite element modeling. We demonstrate that the derived model allows a powerful analysis of experimental data comprising an estimation of the weak spot parameters i.e. its critical current and the length of the defect zone.

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Scanning Hall-probe microscopy for site-specific observation of microstructure in superconducting wires and tapes for the clarification of their performance bottlenecks

Cited by 12 publications

References 52 publications

Frontiers of graphene-based Hall-effect sensors

Frontiers of graphene-based Hall-effect sensors

Chemical Solution Deposition of Insulating Yttria Nanolayers as Current Flow Diverter in Superconducting GdBa₂Cu₃O_7−δ Coated Conductors

Stability of DC transport in HTS conductor with local critical current reduction

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Scanning Hall-probe microscopy for site-specific observation of microstructure in superconducting wires and tapes for the clarification of their performance bottlenecks

Cited by 12 publications

References 52 publications

Frontiers of graphene-based Hall-effect sensors

Frontiers of graphene-based Hall-effect sensors

Chemical Solution Deposition of Insulating Yttria Nanolayers as Current Flow Diverter in Superconducting GdBa2Cu3O7−δ Coated Conductors

Stability of DC transport in HTS conductor with local critical current reduction

Contact Info

Product

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Chemical Solution Deposition of Insulating Yttria Nanolayers as Current Flow Diverter in Superconducting GdBa₂Cu₃O_7−δ Coated Conductors