The influences of the second harmonics together with the asymmetries of junctions on the voltage–current characteristics of high T C DC SQUIDs

• Published in: Physica. C, Superconductivity Vol. 471; no. 3; pp. 83 - 90
• Main Author: Eatesami, M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2011
• Subjects: DC SQUIDs; Fokker–Planck equation; Voltage modulation; Fokker–Planck equation; DC SQUIDs; Voltage modulation
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2010.11.003

► We defined two stationary density probability currents for a DC SQUID. ► We proved that the measurable total voltage is in proportion to sum of them. ► The alone asymmetry or the alone second harmonic considerations are inadequate. ► Jointly considerations can lead to the reduction of maximum voltage modulation. ► Also the increase of biasing current that provides it. We consider a superconducting quantum interference device having two arbitrary different over damped junctions transporting different currents. By replacing the governed two-dimensional Fokker–Planck equation with two one-dimensional equations, two density probability currents are appeared which determine the statistical average of the time-averaged total voltage across the device. To obtain the density probability currents, two coupled integral equations are introduced. These equations together with two other equations coming from normalizing conditions, found one generalized formulation for the voltage–current characteristics of the device. Based on that, the voltage–current characteristics of large inductance asymmetric DC SQUIDs having first and second harmonics in their current-phase relations are obtained and some predictions are illustrated.