A Cross-Whiskers Junction as a Novel Fabrication Process for Intrinsic Josephson Junction

TL;DR

This paper introduces a simple, micro-fabrication-free method to create intrinsic Josephson junctions using cross-whiskers of Bi2Sr2CaCu2O8+d on MgO substrates, demonstrating clear Josephson behavior at low temperatures.

Contribution

It presents a novel fabrication process for intrinsic Josephson junctions by crossing whisker crystals without micro-fabrication techniques.

Findings

Clear multiple-branch I-V characteristics at 5K

Critical current density estimated at 1170 A/cm2

Branch-structure suppressed by magnetic field above 1kOe

Abstract

A Bi2Sr2CaCu2O8+d cross-whiskers junction has been successfully discovered as a novel intrinsic Josephson junction without using any technique for micro-fabrication. Two Bi2Sr2CaCu2O8+d whisker crystals were placed crosswise on a MgO substrate and heated at 850C for 30 min. They were electrically connected at their c-planes. The measurement terminals were made at the four ends of the whiskers. The I-V characteristics of the cross-whiskers junction at 5K were found to show a clear multiple-branch structure with a spacing of approximately 15 mV that is a feature of the intrinsic Josephson junction. The critical current density Jc was estimated to be 1170 A/cm2. The branch-structure was strongly suppressed by the magnetic field above 1kOe.