Current Distribution and Transition Width in Superconducting Transition-Edge Sensors

Published: December 13, 2012

Author(s)

Daniel S. Swetz, Douglas A. Bennett, Daniel R. Schmidt, Joel N. Ullom

Abstract

Present models of the superconducting-to-normal transition in transition-edge sensors (TESs)do not describe the current distribution within a biased TES. This distribution is complicated by normal-metal features that are integral to TES design. We present a model with one free parameter that describes the evolution of the current distribution with bias. To probe the current distribution experimentally, we fabricated TES devices with di erent current return geometries. Devices where the current return geometry mirrors current flow within the device have sharper transitions thus allowing for a direct test of the current ow model. Measurements from these devices show that current meanders through a TES low in the resistive transition but ows across the normal-metal features by 40 percent of the normal-state resistance. Comparison of transition sharpness between device designs reveals that self-induced magnetic elds play an important role in determining the width of the superconducting transition.
Citation: Physical Review Letters
Volume: 101
Issue: 24
Pub Type: Journals

Keywords

superconducting sensor, magnetic fields, transition width
Created December 13, 2012, Updated November 10, 2018