Size effects on the quenching to the normal state in YBa2Cu3O7-delta thin film superconductors

TL;DR

This study investigates how the width of YBa2Cu3O7-delta superconducting microbridges influences quenching behavior under high current densities, revealing that self-heating causes transition to a dissipative state.

Contribution

It demonstrates experimentally that quenching in narrow superconducting microbridges is primarily driven by self-heating effects, with width dependence observed for high current densities.

Findings

Flux-flow resistivity is width independent.

Quenching current density depends strongly on microbridge width.

Self-heating causes transition to dissipative state at high current densities.

Abstract

To probe the quenching mechanisms under high current densities, current-voltage curves have been measured in YBa2Cu3O7-delta thin film microbridges with widths lower than the thermal diffusion length. This condition was obtained by using microbridge widths under 100 micrometers and stepped ramps of one millisecond step duration. Whereas the flux-flow resistivity is found to be microbridge-width independent, strong width dependence of the quenching current density is observed. These results provide a direct experimental demonstration that for high current densities varying in the millisecond range the transition to a highly dissipative state is due to self heating driven by "conventional" (non-singular) flux flow effects.