Abstract
We discuss the response of an rf-SQUID formed by anomalous Josephson junctions embedded in a superconducting ring with a non-negligible inductance. We demonstrate that a properly sweeping in-plane magnetic field can cause both the total flux and the current circulating in the device to modulate and to behave hysteretically. The bistable response of the system is analyzed as a function of the anomalous phase shift at different values of the screening parameter, in order to highlight the parameter range within which a hysteretic behavior can be observed. The magnetic flux piercing the SQUID ring is demonstrated to further modulate the hysteretical response of the system. Moreover, we show that the anomalous phase shift can be conveniently determined through the measurement of the out-of-plane magnetic field at which the device switches to the voltage state and the number of trapped flux quanta changes. Finally, we compare the response of two different device configurations, namely, a SQUID including only one or two anomalous junctions. In view of these results, the proposed device can be effectively used to detect and measure the anomalous Josephson effect.
Highlights
A superconducting quantum-interference device (SQUID), which is formed embedding Josephson junctions (JJs) in a phase-sensitive superconducting loop geometry, is an efficient and versatile tool to measure phase-coherent effects
We are dealing with JJs with the ground state corresponding to a finite phase shift, 0 < φ0 < π, in the current-phase relations (CPRs), Iφ = Ic sin(φ + φ0) (Ic is the critical current of the junction)
We study the hysteretical response of an inductive φ0 rf-SQUID, namely, a superconducting ring with a non-negligible inductance interspersed by φ0 junctions, when both the in-plane and the out-of-plane magnetic field components are taken into account
Summary
A superconducting quantum-interference device (SQUID), which is formed embedding Josephson junctions (JJs) in a phase-sensitive superconducting loop geometry, is an efficient and versatile tool to measure phase-coherent effects. It has been used for exploring potential signatures of unconventional superconductivity and other novel physical phenomena [1,2,3,4,5,6,7]. Conventional superconductors have been combined in a SQUID geometry with other materials, such as ferromagnets [2], topological insulators [8,9], or nanowires [4,10], in order to study nontrivial current-phase relations (CPRs) [11,12,13,14]. Josephson interferometers were effectively used to study heat currents [18,19] in phase-dependent caloritronics
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