Theory of the voltage-current characteristic of high T-c DC SQUIDs

摘要

A new analytic theory for the voltage-current characteristic of symmetric high T-c DC SQUIDs is developed. The theory is based on analytical solution of a two-dimensional Fokker-Planck equation, which describes the dynamical behavior of DC SQUID in presence of thermal noise. For high T-c DC SQUIDs operating at 77 K with L > 100 pH, where L is geometrical inductance of DC SQUID loop, our theory is valid for any values of critical currents of Josephson junctions and it allows a correct evaluation of transfer function of practical high T-c DC SQUIDs. The theoretical voltage modulation is shown to be in a good agreement with the results of known computer simulations. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 20]