On the origin of reentrance in 2D Josephson junction arrays

摘要

A comparative study of the magnetic properties of shunted and unshunted two-dimensional Josephson junction arrays (2D-JJA) is presented. Using a single-plaquette approximation of the 2D-JJA model, we were able to successfully fit all our experimental data ( for the temperature, AC and DC field dependencies of susceptibility) and demonstrate that the dynamic reentrance of AC susceptibility is directly linked to the value of the Stewart-McCumber parameter beta(C). Based on extensive numerical simulations, a phase diagram beta(C)-beta(L) is plotted which demarcates the border between the reentrant and non-reentrant behavior in the arrays.