Fabrication of Magnetometers With Multiple-SQUID Arrays

Matsuda, Masaki; Nakamura, Kenji; Mikami, Hiroshi; Kuriki, Shinya

doi:10.1109/tasc.2005.850069

Cited by 14 publications

(11 citation statements)

References 15 publications

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“…Recent advances that led to nano-SQUIDs make possible the fabrication of SQUID metamaterials at the nanoscale [28]. The use of SQUID arrays in dc current sensors [29], filters [30,31], magnetometers [32], amplifiers [33][34][35], radiation detectors [36], flux-to-voltage converters [37], compact antennas [38,39], linear rf low noise amplifiers [40,41], output amplifiers for rapid single flux quantum (RSFQ) circuits [42,43], drivers for digital transmitters [44], as well as in RSFQ electronics [45], has been suggested and realized in the past. However, in most of these works the SQUIDs in the arrays were actually directly coupled through conducting paths.…”

Section: Introductionmentioning

confidence: 99%

Multistability and self-organization in disordered SQUID metamaterials

Lazarides

Tsironis

2013

Supercond. Sci. Technol.

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Planar arrays of magnetoinductively coupled rf SQUIDs (Superconducting Quantum Interference Devices) belong to the emergent class of superconducting metamaterials that encompass the Josephson effect. These SQUID-based metamaterials acquire their electromagnetic properties from the resonant characteristics of their constitutive elements, i.e., the individual rf SQUIDs. In its simplest version, an rf SQUID consists of a superconducting ring interrupted by a Josephson junction. We investigate the response of a two-dimensional rf SQUID metamaterial to frequency variation of an externally applied alternating magnetic field in the presence of disorder arising from critical current fluctuations of the Josephson elements; in effect, the resonance frequencies of individual SQUIDs are distributed randomly around a mean value. Bistability is observed in the total current-frequency curves both in ordered and disordered SQUID metamaterials; moreover, bistability is favoured by disorder through the improvement of synchronization between SQUID oscillators. Relatively weak disorder widens significantly the bistability region by helping the system to self-organize itself and leads to nearly homogeneous states that change smoothly with varying driving frequency. Also, the total current of the metamaterial is enhanced compared with that of uncoupled SQUIDs, through the synergetic action of coupling and synchronization. The existence of simultaneously stable states that provide either high or low total current, allows the metamaterial to exhibit different magnetic responses that correspond to different values of the magnetic permeability. and provide either high or low total current, allows the metamaterial to exhibit two different magnetic responses that correspond to different values of its magnetic permeability. At low power of the incident field, high-current states exhibit extreme diamagnetic properties corresponding to negative magnetic permeability in a narrow frequency region.

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Section: Introductionmentioning

confidence: 99%

Multistability and self-organization in disordered SQUID metamaterials

Lazarides

Tsironis

2013

Supercond. Sci. Technol.

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“…In the existence of spread, is typically not identical to . For this case, (4) can be generalized to include the geometrical asymmetry: (5) in which and are the shape parameters of gamma distribution. In terms of and , the geometrical-asymmetry parameter is .…”

Section: Formentioning

confidence: 99%

“…To minimize the contact resistance in electrical measurements, the contact pads were coated by 200 nm Au films before lithography processes. The hole size of the SQUID loop is , and the bridge width of junctions is 5 . The displacement, i.e.…”

Section: A Experimental Detailsmentioning

confidence: 99%

“…However, the further developments of the devices comprising many junctions, e.g. the series-and parallel-SQUID arrays [4], [5], the superconducting quantum interference grating [6], and the superconducting quantum interference filter (SQIF), [7], are limited by the spread in critical current . Even with the optimized fabrication processes, the significant variation in remains [8], [9].…”

Section: Introductionmentioning

confidence: 99%

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Spreads in Critical Current and Normal Conductance of High-$T_{\rm c}$ dc SQUID

Jeng

Wang

et al. 2009

IEEE Trans. Appl. Supercond.

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The statistical behaviors of the critical current ( c ) and the normal conductance ( n ) of high-c dc SQUIDs were investigated theoretically and experimentally. The voltage-current and voltage-flux characteristics of 38 SQUIDs fabricated on a chip were measured by using a switching-channel cryostat, which can characterize up to 43 elements individually in a series array. It was found that the spatial correlation in c between the neighboring SQUIDs is low, which implies that the critical current can be taken as a spatially independent random variable. The c and n histograms follow the gamma distributions. In addition, the statistical linear correlation between ln c and ln n is 0.6, which suggests that the c spread is partly originated from the variation in local oxygen content of bicrystal junctions.

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“…The high-transition-temperature superconducting quantum interference devices (high-T C DC SQUIDs) each consisting of two bicrystal Josephson junctions are key elements for many sensitive instruments such as extremely low noise magnetometers 1,2,3 , the series-and parallel-SQUID arrays 4,5 , the superconducting quantum interference grating 6,7 , etc.…”

Section: Introductionmentioning

confidence: 99%

Voltage-current and voltage-flux characteristics of asymmetric high TC DC SQUIDs

Novikov,

Greenberg,

Schultze

et al. 2008

Preprint

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We report measurements of transfer functions and flux shifts of 20 on-chip high TC DC SQUIDs half of which were made purposely geometrically asymmetric. All of these SQUIDs were fabricated using standard high TC thin film technology and they were single layer ones, having 140 nm thickness of YBa2Cu3O7−x film deposited by laser ablation onto MgO bicrystal substrates with 24 0 misorientation angle. For every SQUID the parameters of its intrinsic asymmetry, i. e., the density of critical current and resistivity of every junction, were measured directly and independently. We showed that the main reason for the on-chip spreading of SQUIDs' voltage-current and voltage-flux characteristics was the intrinsic asymmetry. We found that for SQUIDs with a relative large inductance (L > 120 pH) both the voltage modulation and the transfer function were not very sensitive to the junctions asymmetry, whereas SQUIDs with smaller inductance (L ≃ 65 − 75 pH) were more sensitive. The results obtained in the paper are important for the implementation in the sensitive instruments based on high TC SQUID arrays and gratings.

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Fabrication of Magnetometers With Multiple-SQUID Arrays

Cited by 14 publications

References 15 publications

Multistability and self-organization in disordered SQUID metamaterials

Multistability and self-organization in disordered SQUID metamaterials

Spreads in Critical Current and Normal Conductance of High-$T_{\rm c}$ dc SQUID

Voltage-current and voltage-flux characteristics of asymmetric high TC DC SQUIDs

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