Bicrystalline Grain Boundary and Hybrid SNS Junctions Based on Ba-122 Thin Films

TL;DR

This study explores Josephson junctions based on Co-doped Ba-122 thin films, demonstrating their properties through various hybrid and grain boundary configurations, revealing characteristic RSJ behavior and measurable ICRN products.

Contribution

It introduces new hybrid SNS' and edge-type Josephson junctions using Ba-122 thin films, expanding understanding of their electrical properties and potential applications.

Findings

All junction types showed RSJ-like behavior.

Measured ICRN products ranged from 12.3 to 20.2 μV.

Excess current observed in all junctions.

Abstract

To investigate the properties of iron-based superconductors, we examined different kinds of Josephson junctions using Co-doped Ba-122 thin films. Based on bicrystalline SrTiO3 substrates we prepared grain boundary (GB) junctions, which showed clear Josephson effects. We present electrical measurements at varying temperatures and magnetic fields. Furthermore, we prepared hybrid junctions using thin film technique. Confined by a Ba-122 base electrode (S) and a PbIn counter electrode (S') two different geometries of hybrid junctions are formed: a planar SNS' junction with a gold barrier (N) in between and an edge-type junction with an interface-engineered barrier. All three kinds of junctions showed asymmetric resistively shunted junction-like (RSJ) behavior with ICRN products of 20.2 /mu V (GB junctions), 18.4 /mu V (planar SNS' junctions) and 12.3 /mu V (edge-type junctions), respectively. An excess current could be observed at all junctions.