Nucleation of superconductivity in Al mesoscopic disk with magnetic dot

TL;DR

This study investigates how a magnetic dot influences the nucleation of superconductivity in a mesoscopic aluminum disk, revealing asymmetry in the critical magnetic field and aligning experimental results with theoretical predictions.

Contribution

It demonstrates the effect of a magnetic dot on superconductivity nucleation and provides experimental-theoretical agreement for Tc(B) in mesoscopic disks.

Findings

Asymmetry in Tc(B) with respect to magnetic field direction

Enhanced critical field when field aligns with magnetic dot magnetization

Good agreement between experimental data and theoretical models

Abstract

We have studied the nucleation of superconductivity in a mesoscopic Al disk wit a Co/Pd magnetic dot placed on the top by measuring the normal superconducting phase boundary Tc(B). The measurements have revealed a pronounced asymmetry with respect to the direction of the applied magnetic field, indicating an enhancement of the critical field when an applied magnetic field is oriented parallel to the magnetization of the magnetic dot. The theoretical Tc(B) curve is in a good agreement with the experimental data.