Control of the effective value of the critical current of the RF SQUID by the high-frequency electromagnetic field

TL;DR

This paper investigates how high-frequency electromagnetic fields can be used to control the effective critical current of RF SQUIDs, enhancing their sensitivity and conversion efficiency through experimental and analytical methods.

Contribution

It demonstrates a method to adjust the RF SQUID's hysteretic behavior and improve its performance using high-frequency electromagnetic fields, supported by experimental verification.

Findings

Parameter controlling hysteresis can be tuned with high-frequency fields

Significant increase in RF SQUID sensitivity observed

Effective control of critical current achieved

Abstract

An analysis of the influence of the high-frequency electromagnetic field on the amplitude-frequency and signal characteristics of RF SQUID and experimental verification are carried out. At low parameter , the RF SQUID behavior is well described analytically by the theoretical model. In experiment, basic operation scheme is used in which the interferometer is inductively connected to a resonant tank circuit driven by RF current at a frequency close to the resonance frequency of the tank. It is shown that parameter , which distinguishes between hysteretic and non-hysteretic regimes, can be effectively adjusted to a desired value by applying the high-frequency field of a certain amplitude and frequency much higher than tank resonant frequency. A significant increase in the conversion factor and sensitivity of the RF SQUID during this adjustment is discussed.