Eur. Phys. J. B 44, 57-62 (2005)
https://doi.org/10.1140/epjb/e2005-00099-1

The influence of the second harmonic in the current-phase relation on the voltage-current characteristic of high T_C DC SQUID

¹ Novosibirsk State Technical University, 20 K. Marx Ave., 630092 Novosibirsk, Russia
² Institute for Physical High Technology, 07702, Jena, Germany

Corresponding author: ^a greenbergy@online.nsk.su

Received: 13 July 2004
Revised: 9 December 2004
Published online: 16 April 2005

Abstract

A theory for the voltage-current characteristic in high T_C DC SQUIDs (Superconducting Quantum Interference Devices), which accounts for a second harmonic in the junction current-phase relation, is developed. It is shown that the small inductance DC SQUIDs can be used for the investigation of the second harmonic via its influence on the voltage-flux curve. If the second harmonic is perceptible, then for large inductance DC SQUIDs the theory can explain the substantial deviations of the experimental voltage modulation from theoretical predictions and computer simulations based on conventional sinusoidal current-phase relation. The detail comparison with the experiment is performed.