Characterization of large two-dimensional YBa₂Cu₃O_7–δ SQUID arrays

Large two-dimensional SQUID arrays were made using the step-edge Josephson junction process. The performance of the arrays is analyzed with respect to determining the conditions under which the optimal performance is achieved. We find that optimization of the field-voltage transfer function V_B is reached at a specific temperature and device current bias point, and arrive at an empirical expression describing the dependence of V_B on the critical current and dynamic resistance of the SQUID array and as a function of temperature. The empirical expression for V_B of the SQUID arrays is similar to that given by well known theoretical models for a single SQUID. (paper)