Stochastic resonance in an RF SQUID with shunted ScS junction

• We numerically simulate stochastic resonance in an RF SQUID with ScS Josephson junction.
• We use the zero-temperature approximation for the ScS superconducting current–phase relation.
• The potential energy has a finite-height barrier for any arbitrary small parameter βLβL.
• ScS-based SQUIDs are more suitable for SR amplification at ultralow temperatures.
• The concept of “Just-In-Place Amplification” is introduced.

Using a point (superconductor–constriction–superconductor, ScS) contact in a single-Josephson-junction superconducting quantum interference device (RF SQUID) provides stochastic resonance conditions at any arbitrary small value of loop inductance and contact critical current, unlike SQUIDs with more traditional tunnel (superconductor–insulator–superconductor, SIS) junctions. This is due to the unusual potential energy of the ScS RF SQUID which always has a barrier between two wells, thus making the device bistable. This paper presents the results of a numerical simulation of the stochastic dynamics of the magnetic flux in an ScS RF SQUID loop affected by band-limited white Gaussian noise and low-frequency sine signals of small and moderate amplitudes. The difference in stochastic amplification of RF SQUID loops incorporating ScS and SIS junctions is discussed.