The dynamics of high-frequency DC RSQUID oscillators

C.M. Pegrum

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Josephson circuit simulation software has been used to study the properties of a range of two-junction DC RSQUIDs configured as current-controlled heterodyne oscillators. We find that, if the loop inductance is small, their current-voltage curves are modified substantially due to self-induced Shapiro steps. When the heterodyne frequency is comparable with the Josephson frequency of the junctions the step amplitude becomes very large and additional features are seen, including sub-harmonic steps and step tails. We point out that conventional DC RSQUIDs generally have too large a loop inductance for some of these effects to be seen in the I-V curves, and we suggest that nanofabrication techniques could be used to make novel low-inductance RSQUIDs. We have also demonstrated that by applying a sinusoidally varying RF flux to a DC RSQUID it is possible to phase-modulate the heterodyne oscillation, which could have useful practical applications.
Original languageEnglish
Pages (from-to)064004
JournalSuperconductor Science and Technology
Volume22
Issue number6
DOIs
Publication statusPublished - Jun 2009

Fingerprint

Inductance
direct current
oscillators
inductance
Circuit simulation
Nanotechnology
nanofabrication
curves
Fluxes
Electric potential
computer programs
harmonics
oscillations
electric potential
simulation

Keywords

  • superconducting quantum interference devices
  • SQUIDs
  • superconducting logic elements
  • memory devices
  • microelectronic circuits
  • Josephson devices
  • Oscillators
  • pulse generators
  • function generators

Cite this

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title = "The dynamics of high-frequency DC RSQUID oscillators",
abstract = "Josephson circuit simulation software has been used to study the properties of a range of two-junction DC RSQUIDs configured as current-controlled heterodyne oscillators. We find that, if the loop inductance is small, their current-voltage curves are modified substantially due to self-induced Shapiro steps. When the heterodyne frequency is comparable with the Josephson frequency of the junctions the step amplitude becomes very large and additional features are seen, including sub-harmonic steps and step tails. We point out that conventional DC RSQUIDs generally have too large a loop inductance for some of these effects to be seen in the I-V curves, and we suggest that nanofabrication techniques could be used to make novel low-inductance RSQUIDs. We have also demonstrated that by applying a sinusoidally varying RF flux to a DC RSQUID it is possible to phase-modulate the heterodyne oscillation, which could have useful practical applications.",
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The dynamics of high-frequency DC RSQUID oscillators. / Pegrum, C.M.

In: Superconductor Science and Technology, Vol. 22, No. 6, 06.2009, p. 064004.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The dynamics of high-frequency DC RSQUID oscillators

AU - Pegrum, C.M.

PY - 2009/6

Y1 - 2009/6

N2 - Josephson circuit simulation software has been used to study the properties of a range of two-junction DC RSQUIDs configured as current-controlled heterodyne oscillators. We find that, if the loop inductance is small, their current-voltage curves are modified substantially due to self-induced Shapiro steps. When the heterodyne frequency is comparable with the Josephson frequency of the junctions the step amplitude becomes very large and additional features are seen, including sub-harmonic steps and step tails. We point out that conventional DC RSQUIDs generally have too large a loop inductance for some of these effects to be seen in the I-V curves, and we suggest that nanofabrication techniques could be used to make novel low-inductance RSQUIDs. We have also demonstrated that by applying a sinusoidally varying RF flux to a DC RSQUID it is possible to phase-modulate the heterodyne oscillation, which could have useful practical applications.

AB - Josephson circuit simulation software has been used to study the properties of a range of two-junction DC RSQUIDs configured as current-controlled heterodyne oscillators. We find that, if the loop inductance is small, their current-voltage curves are modified substantially due to self-induced Shapiro steps. When the heterodyne frequency is comparable with the Josephson frequency of the junctions the step amplitude becomes very large and additional features are seen, including sub-harmonic steps and step tails. We point out that conventional DC RSQUIDs generally have too large a loop inductance for some of these effects to be seen in the I-V curves, and we suggest that nanofabrication techniques could be used to make novel low-inductance RSQUIDs. We have also demonstrated that by applying a sinusoidally varying RF flux to a DC RSQUID it is possible to phase-modulate the heterodyne oscillation, which could have useful practical applications.

KW - superconducting quantum interference devices

KW - SQUIDs

KW - superconducting logic elements

KW - memory devices

KW - microelectronic circuits

KW - Josephson devices

KW - Oscillators

KW - pulse generators

KW - function generators

UR - http://dx.doi.org/10.1088/0953-2048/22/6/064004

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DO - 10.1088/0953-2048/22/6/064004

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SP - 064004

JO - Superconductor Science and Technology

JF - Superconductor Science and Technology

SN - 0953-2048

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ER -