Tailoring phase slip events through magnetic doping in superconductor-ferromagnet composite films

TL;DR

This study demonstrates that minimal magnetic doping in superconductor-ferromagnet composite films can effectively trigger phase slip events, revealing new insights into their interplay and potential applications in photonics and metrology.

Contribution

It provides experimental evidence that less than 1% magnetic doping can induce phase slip events in composite films, a novel finding in the field.

Findings

Magnetic doping initiates phase slip events in composite films.

Distinct vortex-antivortex and phase slip regimes are observed.

Phase slip features are absent in pure superconducting films.

Abstract

The interplay between superconductivity (SC) and ferromagnetism (FM) when embedded together has attracted unprecedented research interest due to very rare coexistence of these two phenomena. The focus has been mainly put into the proximity induced effects like, coexistence of magnetism and superconductivity, higher critical current, triplet superconductivity etc. However, very little attention has been paid experimentally to the role of magnetic constituent on triggering phase slip processes in the composite films (CFs). We demonstrate that less than 1 at. % of magnetic contribution in the CFs can initiate phase slip events efficiently. Due to advanced state-of-the-art fabrication techniques, phase slip based studies have been concentrated mainly on superconducting nanostructures. Here, we employ wide mesoscopic NbGd based CFs to study the phase slip processes. Low temperature current-voltage characteristics (IVCs) of CFs show stair-like features originated through phase slip events and are absent in pure SC films. Depending on the bias current and temperature, distinct regions, dominated by Abrikosov type vortex-antivortex (v-av) pairs and phase slip events, are observed. The results presented here open a new way to study the phase slip mechanism, its interaction with v-av pairs in two dimensions and hence can be useful for future photonic and metrological applications