Investigation of the Accuracy of Modelling the Current-Voltage Characteristics of DC Superconducting Quantum Interference Device

We proposed equivalent direct current superconducting quantum interference device and evaluation method, which make it possible to obtain current-voltage characteristics of asymmetric direct current superconducting quantum interference device at negligibly small magnetic flux caused by difference in parameters of Josephson junctions. For model synthesis we replaced direct current superconducting quantum interference device by a parallel connection of two nonlinear elements. It is shown that the current-voltage characteristic of direct current superconducting quantum interference device with the asymmetry parameters of critical currents and shunt resistors less than 10
^%
can be represented with great accuracy in the form of the current-voltage characteristic of an equivalent single Josephson junction with equivalent parameters. Its relative approximation error is less than 0.5%. This conclusion is in complete agreement with the well-known results of other authors. For small deviations from symmetry, the proposed method allowed us to refine the current-voltage characteristic. We discussed the reasons why the experimental current-voltage characteristics differ from the theoretical ones.