Field dependence of the resistive transition for a square wire network

Abstract

We report the results of a study of square aluminum wire networks in a magnetic field. The ${\mathit{T}}_{\mathit{c}}$-versus-(\ensuremath{\Phi}/${\mathrm{\ensuremath{\Phi}}}_{0}$) phase boundary defined at different points in the resistive transition was measured. When measuring low in the resistive transition, we see fine structure at rational fractions of the flux quantum f=\ensuremath{\Phi}/${\mathrm{\ensuremath{\Phi}}}_{0}$=p/q, out to q=8. We also measured the field dependence of the resistive transition at many f=\ensuremath{\Phi}/${\mathrm{\ensuremath{\Phi}}}_{0}$. The effect of the rational fields on the width of the transition is more dramatic than the effect on the phase boundary itself. Using a simple model, we can correctly order the width of the resistive transitions at the commensurate flux fillings.