On the transfer function of a weak link ultra-low capacity RF-SQUID

P. Carelli, I. Modena, Gian Luca Romani

G. J. Ehnholm

Jason F. Ralph, Terrence D. Clark, Robert J. Prance +2 more

We use a discrete-field model for the quantum evolution of distributed superconducting circuits to calculate the effective capacitance for a radio-frequency-SQUID magnetometer: a large-capacitance superconducting ring containing an ultra-small-capacitance weak link. We demonstrate that the self-capacitance of the weak link can dominate the behaviour of the circuit.

H. Lübbig

ANALYSIS OF THE REVERSIBLE MAGNETIZATION OF A RF SQUID CONTAINING A WEAK LINK WITH A NON-SINUSOIDAL CURRENT PHASE RELATIONSHIP was published in SQUID ’80. Superconducting Quantum Interference Devices and their Applications on page 591.

Oleg V. Snigirev

Young Ho Lee, KK Yu, J-M Kim +4 more

Radio-frequency (RF) amplifiers based on direct current (DC) superconducting quantum interference device (SQUID) have low-noise performance for precision physics experiments. Gain curves of SQUID RF amplifiers depend on several parameters of the SQUID and operation conditions. We are developing SQUID RF amplifiers for application to measure very weak RF signals from ultra-low-temperature high-magnetic-field microwave cavity in axion search experiments. In this study, we designed, fabricated and characterized SQUID RF amplifiers with different SQUID parameters, such as number of input coil turn, shunt resistance value of the junction and coupling capacitance in the input coil, and compared the results.