High quality step-edge substrates for high-Tc superconducting devices

Wu, Chau-Chung; Chen, Ming‐Ju; Chen, Jung-Chieh; Chen, K. L.; Hong, Yang; Hsu, Ming Shinn; Lai, T. S.; Tsai, Yu Sheng; Horng, Herng Er; Chen, J. H.; Jeng, Jin-Tsong

doi:10.1063/1.2179407

Cited by 12 publications

(3 citation statements)

References 19 publications

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“…A second etching step was found to significantly improve the profile of the etched steps by cleaning the surface prior to YBCO film deposition [16]. Other workers have subsequently found this second etching step useful [21].…”

Section: Introductionmentioning

confidence: 99%

YBCO step-edge junctions with highI_cR_n

Mitchell¹,

Foley

2010

Supercond. Sci. Technol.

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Step-edge junctions represent one type of grain boundary Josephson junction employed in high-temperature superconducting junction technology. To date, the majority of results published in the literature focus on [001]-tilt grain boundary junctions (GBJs) produced using bicrystal substrates. We investigate the step morphology and YBCO (yttrium barium copper oxide) film structure of YBCO-based step-edge junctions on MgO [001] substrates which structurally resemble [100]-tilt junctions. High-resolution electron microscopy reveals a clean GBJ interface of width ∼1 nm and a single junction at the top edge. The dependence of the transport properties on the MgO step-edge and junction morphology is examined at 4.2 K, to enable direct comparison with results for other junction studies such as [001]-tilt and [100]-tilt junctions and building on previously published 77 K data. MgO step-edge junctions show a slower reduction in critical current density with step angle compared with [001]-tilt junctions. For optimized step parameters, transport measurements revealed large critical current and normal resistance (I c R N ) products (∼3-5 mV), comparable with the best results obtained in other kinds of [100]-tilt GBJs in YBCO at 4.2 K. Junction-based devices such as SQUIDs (superconducting quantum interference devices) and THz imagers show excellent performance when MgO-based step-edge junctions are used.

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Section: Introductionmentioning

confidence: 99%

YBCO step-edge junctions with highI_cR_n

Mitchell¹,

Foley

2010

Supercond. Sci. Technol.

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“…A proposed design of serial SQUID arrays has significantly improved the fabrication [82] yield. High quality bi-crystal [83], step-edge substrates [84] and high quality YBa 2 Cu 3 O y films are required to achieve high fabrication yields.…”

Section: Challenges and Perspectivementioning

confidence: 99%

Advances in biomagnetic research using high-T_csuperconducting quantum interference devices

Yang

Horng

Yang

et al. 2009

Supercond. Sci. Technol.

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This review reports the advances of biomagnetic research using high- Tc superconducting quantum interference devices (SQUIDs). It especially focuses on SQUID-detected magnetocardiography (MCG), magnetically labeled immunoassays (MLIs) as well as nuclear magnetic resonance and imaging (NMR/MRI). The progress in MCG that scientists have made and the encountered challenges are discussed here. This study includes the early detection of the electromagnetic change in cardiac activity in animal studies of hypercholesterolemic rabbits, which suggests the possibility of early diagnosis of cardiac disease in clinical applications. The progress on MLIs using measurements of remanence, magnetic relaxation and magnetic susceptibility reduction is presented. The wash-free immunomagnetic reduction shows both high sensitivity and high specificity. NMR/MRI of high spectral resolution and of high signal-to-noise ratio are addressed and discussed. The proton–phosphate J-coupling of trimethyl phosphate ((CH3)3PO4) in one shot in microtesla fields is demonstrated. The prospects of biomagnetic applications are addressed.

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“…[8] In particular, we note that Wu et al investigated the influence of the step angle on the fabrication of YBCO DC SQUIDs with SEJs. [9] Using MgO as the substrate material, they reported a SQUID having white flux noise around 60 µΦ 0 / √ Hz. As for the ratio of the film thickness d to the step height h, d/h, the previous studies indicated that it should have a value between 2/3 and 1 for PLD-grown YBCO films and about 1/2 for sputtered ones.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and properties of high performance YBa₂Cu₃O_7−δradio frequency SQUIDs with step-edge Josephson junctions

Liu¹,

Wei²,

Wang³

et al. 2014

Chinese Phys. B

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We describe the fabrication of high performance YBa 2 Cu 3 O 7−δ (YBCO) radio frequency (RF) superconducting quantum interference devices (SQUIDs), which were prepared on 5 mm×5 mm LaAlO 3 (LAO) substrates by employing stepedge junctions (SEJs) and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47 • to 61 • , which is steep enough to ensure the formation of grain boundaries (GBs) at the step edges. The YBCO film was deposited using the pulsed laser deposition (PLD) technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH. Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/Φ 0 , a white flux noise of 29 µΦ 0 / √ Hz, and the magnetic field sensitivity as high as 80 fT/ √ Hz. These devices have been applied in magnetocardiography and geological surveys.

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High quality step-edge substrates for high-Tc superconducting devices

Cited by 12 publications

References 19 publications

YBCO step-edge junctions with highI_cR_n

YBCO step-edge junctions with highI_cR_n

Advances in biomagnetic research using high-T_csuperconducting quantum interference devices

Fabrication and properties of high performance YBa₂Cu₃O_7−δradio frequency SQUIDs with step-edge Josephson junctions

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High quality step-edge substrates for high-Tc superconducting devices

Cited by 12 publications

References 19 publications

YBCO step-edge junctions with highIcRn

YBCO step-edge junctions with highIcRn

Advances in biomagnetic research using high-Tcsuperconducting quantum interference devices

Fabrication and properties of high performance YBa2Cu3O7−δradio frequency SQUIDs with step-edge Josephson junctions

Contact Info

Product

Resources

About

YBCO step-edge junctions with highI_cR_n

YBCO step-edge junctions with highI_cR_n

Advances in biomagnetic research using high-T_csuperconducting quantum interference devices

Fabrication and properties of high performance YBa₂Cu₃O_7−δradio frequency SQUIDs with step-edge Josephson junctions