Optimization of step-edge substrates for high-TC superconducting devices

Wu, Chau-Chung; Chen, M.J.; Hsu, Miao Hsing; Chen, J.C.; Chen, K.L.; Chen, J.H.; Jeng, Jin-Tsong; Lai, T. S.; Horng, Herng-Er; Yang, Hong-Chang

doi:10.1016/j.physc.2005.10.006

Cited by 6 publications

(3 citation statements)

References 19 publications

(26 reference statements)

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“…However, the design of the SQUID array could provide the chance to select the SQUIDs with similar I c for serial connection. Moreover, the nonuniform field around the SQUIDs causes an incoherent phase relation in V −Φ curves in SQUIDs [19]. If each SQUID in the array is subjected to the same magnetic field environment, the phases of each SQUID in the array must be identical in the time domain to significantly enhance the voltage signal.…”

Section: B Design Of Magnetometers and Gradiometers With Squids In Smentioning

confidence: 99%

Low-Noise Serial High- $T_{c}$ $\hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{y}$ Superconducting Quantum Interference Devices Based on Bicrystal Junctions

Chen

Liao

Chen

et al. 2015

IEEE Trans. Appl. Supercond.

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The fabrication of high-T c YBa 2 Cu 3 O y (YBCO) superconducting quantum interference devices (SQUIDs) that produce low flux noise while maintaining a high fabrication yield continues to challenge scientists. In this paper, we report the characterization of low-noise serial high-T c SQUIDs for biomagnetic applications. Epitaxial high-T c YBCO thin films with a root-mean-square surface roughness less than 5 nm are optimized for the low-noise serial SQUID coupled to a common pickup coil to form magnetometers and gradiometers. Current-voltage curves, voltage-flux curves, and flux noise of SQUID devices are characterized. A smooth surface morphology across the bicrystal line is essential for SQUIDs to show good characteristics. The field sensitivity is improved by a factor of (2) 1/2 with the designed serial SQUID array, which is coupled to a common pickup loop. This is demonstrated, and its fabrication yield is higher than 80% for devices with peak-to-peak voltage V PP ≥ 15 μV. The challenges and perspectives of the high-T c serial SQUID array for biomagnetic applications are addressed and discussed.

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Section: B Design Of Magnetometers and Gradiometers With Squids In Smentioning

confidence: 99%

Low-Noise Serial High- $T_{c}$ $\hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{y}$ Superconducting Quantum Interference Devices Based on Bicrystal Junctions

Chen

Liao

Chen

et al. 2015

IEEE Trans. Appl. Supercond.

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“…Some of the highest critical current densities at 77 K and highest film uniformities have been achieved in YBa 2 Cu 3 O 7−δ films grown on commercially available (1 0 0) SrTiO 3 substrates (Huhne et al, 2006;Jia et al, 2002;2003;Ortiz-Diaz et al, 2004a;Sathyamurthy et al, 2003;Varanasi et al, 2008;Wang et al, 2005;Wee et al, 2005;Wu et al, 2005;Ying et al, 2009). However, SrTiO 3 is fairly expensive, has high dielectric constant, and undergoes phase transition at ∼ 110 K. LaGaO 3 with ∼ 0.5% mismatch it is neither cheap nor twin free (Cyrot & Pavuna, 1992).…”

Section: Superconductivity Elementary Notions and Relevant Propertiesmentioning

confidence: 99%

Properties of YBa2Cu3O7−δ Superconducting Films on Sr2YSbO6 Buffer Layers

Ortiz-Diaz¹,

Téllez²,

Roa-Rojas³

2012

Superconductors - Properties, Technology, and Applications

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“…It seems possible to further reduce the field noise by using a high T c serial SQUID array. However, for the works reported to date [8][9][10] the performances of magnetometers in serial arrays are limited by the small effective area and the spread of the junction parameters. Briefly, some other techniques must be applied to exploit the advantages of the serial SQUID array for low noise magnetometers.…”

Section: Introductionmentioning

confidence: 99%

A highly sensitive YBCO serial SQUID magnetometer with a flux focuser

Hsu

Chen

et al. 2006

Supercond. Sci. Technol.

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We have designed and fabricated a low noise, high T c superconducting quantum interference device (SQUID) magnetometer with an improved yield. In order to reduce the field noise level of the magnetometer, we increased the voltage modulation depth with a series SQUID array and enhanced the effective area with a flux focuser. Ten washer-type SQUIDs were connected in series, thereby increasing the voltage flux transfer function by a factor of 10. An enhancement in effective area by a factor of 5 was achieved by coupling the 10-SQUID array to a single-layered flux focuser. For the directly coupled SQUID array magnetometer, the yield was improved by selecting the best SQUIDs to have in series in order to reduce the flux noise. The magnetic field sensitivity of 40 fT Hz −1/2 in the white regime and 100 fT Hz −1/2 at 1 Hz is demonstrated by using a single layer of high T c film. The proposed high yield magnetometers would be suitable for building low noise multi-channel magnetocardiographs.

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Optimization of step-edge substrates for high-TC superconducting devices

Cited by 6 publications

References 19 publications

Low-Noise Serial High- $T_{c}$ $\hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{y}$ Superconducting Quantum Interference Devices Based on Bicrystal Junctions

Low-Noise Serial High- $T_{c}$ $\hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{y}$ Superconducting Quantum Interference Devices Based on Bicrystal Junctions

Properties of YBa2Cu3O7−δ Superconducting Films on Sr2YSbO6 Buffer Layers

A highly sensitive YBCO serial SQUID magnetometer with a flux focuser

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