MgB2 tunnel junctions with native or thermal oxide barriers

TL;DR

This paper reports on the fabrication and characterization of MgB2 tunnel junctions using native and thermal oxide barriers, demonstrating their stability and varied barrier properties for potential superconducting applications.

Contribution

It introduces a method to create MgB2 tunnel junctions with native oxide barriers that withstand high-temperature deposition, expanding fabrication options.

Findings

Barriers exhibit a wide range of heights and widths.

Native oxide barriers survive 300°C deposition.

Junctions are suitable for superconducting device applications.

Abstract

MgB2 tunnel junctions (MgB2/barrier/MgB2) were fabricated using a native oxide grown on the bottom MgB2 film as the tunnel barrier. Such barriers therefore survive the deposition of the second electrode at 300oC, even over junction areas of ~1 mm2. Studies of such junctions, and those of the type MgB2/native or thermal oxide/metal (Pb, Au, or Ag) show that tunnel barriers grown on MgB2 exhibit a wide range of barrier heights and widths.