The phase boundary of superconducting niobium thin films with antidot arrays fabricated with microsphere photolithography

TL;DR

This study explores how patterned antidot arrays in niobium thin films influence their superconducting phase boundary, revealing modulations in critical current and Little-Parks oscillations due to vortex lattice interactions.

Contribution

It provides experimental insights into the effects of microsphere photolithography-patterned antidot arrays on the superconducting phase boundary of niobium films, highlighting vortex pinning phenomena.

Findings

Pronounced modulations of critical current with magnetic field.

Observation of Little-Parks oscillations in critical temperature.

Evidence of commensurable states between vortex lattice and antidot array.

Abstract

The experimental investigation of the $I_c(B)$--$T_c(B)$ phase boundary of superconducting niobium films with large area quasihexagonal hole arrays is reported. The hole arrays were patterned with microsphere photolithography. We investigate the perforated niobium films by means of electrical directed current transport measurements close to the transition temperature $T_c$ in perpendicularly applied magnetic fields. We find pronounced modulations of the critcal current with applied magnetic field, which we interpret as a consequence of commensurable states between the Abrikosov vortex lattice and the quasihexagonal pinning array. Furthermore, we observe Little-Parks oscillations in the critical temperature vs magnetic field.